diff mbox series

[v3,5/6] can: c_can: prepare to up the message objects number

Message ID 20210228103856.4089-6-dariobin@libero.it
State Superseded
Headers show
Series can: c_can: add support to 64 message objects | expand

Commit Message

Dario Binacchi Feb. 28, 2021, 10:38 a.m. UTC
As pointed by commit c0a9f4d396c9 ("can: c_can: Reduce register access")
the "driver casts the 16 message objects in stone, which is completely
braindead as contemporary hardware has up to 128 message objects".

The patch prepares the module to extend the number of message objects
beyond the 32 currently managed. This was achieved by transforming the
constants used to manage RX/TX messages into variables without changing
the driver policy.

Signed-off-by: Dario Binacchi <dariobin@libero.it>
Reported-by: kernel test robot <lkp@intel.com>

---

Changes in v3:
- Use unsigned int instead of int as type of the msg_obj_* fields
  in the c_can_priv structure.
- Replace (u64)1 with 1UL in msg_obj_rx_mask setting.

Changes in v2:
- Fix compiling error reported by kernel test robot.
- Add Reported-by tag.
- Pass larger size to alloc_candev() routine to avoid an additional
  memory allocation/deallocation.

 drivers/net/can/c_can/c_can.c          | 50 ++++++++++++++++----------
 drivers/net/can/c_can/c_can.h          | 23 ++++++------
 drivers/net/can/c_can/c_can_pci.c      |  2 +-
 drivers/net/can/c_can/c_can_platform.c |  2 +-
 4 files changed, 43 insertions(+), 34 deletions(-)

Comments

Marc Kleine-Budde March 1, 2021, 11:38 a.m. UTC | #1
On 28.02.2021 11:38:54, Dario Binacchi wrote:
[...]

> @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)

>  	while ((idx = ffs(pend))) {

>  		idx--;

>  		pend &= ~(1 << idx);

> -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> +		obj = idx + priv->msg_obj_tx_first;

>  		c_can_inval_tx_object(dev, IF_TX, obj);

>  		can_get_echo_skb(dev, idx, NULL);

>  		bytes += priv->dlc[idx];

> @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)

>  	/* Clear the bits in the tx_active mask */

>  	atomic_sub(clr, &priv->tx_active);

>  

> -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))

> +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))


Do we need 1UL here, too?

Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Marc Kleine-Budde March 1, 2021, 1:08 p.m. UTC | #2
On 01.03.2021 12:38:05, Marc Kleine-Budde wrote:
> On 28.02.2021 11:38:54, Dario Binacchi wrote:

> [...]

> 

> > @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)

> >  	while ((idx = ffs(pend))) {

> >  		idx--;

> >  		pend &= ~(1 << idx);

> > -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> > +		obj = idx + priv->msg_obj_tx_first;

> >  		c_can_inval_tx_object(dev, IF_TX, obj);

> >  		can_get_echo_skb(dev, idx, NULL);

> >  		bytes += priv->dlc[idx];

> > @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)

> >  	/* Clear the bits in the tx_active mask */

> >  	atomic_sub(clr, &priv->tx_active);

> >  

> > -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))

> > +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))

> 

> Do we need 1UL here, too?


There are several more "1 <<" in the driver. As the right side of the
sift operation can be up to 32, I think you should replace all "1 <<"
with "1UL <<".

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Marc Kleine-Budde March 1, 2021, 4:54 p.m. UTC | #3
On 01.03.2021 14:08:45, Marc Kleine-Budde wrote:
> On 01.03.2021 12:38:05, Marc Kleine-Budde wrote:

> > On 28.02.2021 11:38:54, Dario Binacchi wrote:

> > [...]

> > 

> > > @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)

> > >  	while ((idx = ffs(pend))) {

> > >  		idx--;

> > >  		pend &= ~(1 << idx);

> > > -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> > > +		obj = idx + priv->msg_obj_tx_first;

> > >  		c_can_inval_tx_object(dev, IF_TX, obj);

> > >  		can_get_echo_skb(dev, idx, NULL);

> > >  		bytes += priv->dlc[idx];

> > > @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)

> > >  	/* Clear the bits in the tx_active mask */

> > >  	atomic_sub(clr, &priv->tx_active);

> > >  

> > > -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))

> > > +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))

> > 

> > Do we need 1UL here, too?

> 

> There are several more "1 <<" in the driver. As the right side of the

> sift operation can be up to 32, I think you should replace all "1 <<"

> with "1UL <<".


Even better use BIT() for setting single bits and GENMASK() to generate
masks.

Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Dario Binacchi March 1, 2021, 5:21 p.m. UTC | #4
Hi Marc,

> Il 01/03/2021 12:38 Marc Kleine-Budde <mkl@pengutronix.de> ha scritto:

> 

>  

> On 28.02.2021 11:38:54, Dario Binacchi wrote:

> [...]

> 

> > @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)

> >  	while ((idx = ffs(pend))) {

> >  		idx--;

> >  		pend &= ~(1 << idx);

> > -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> > +		obj = idx + priv->msg_obj_tx_first;

> >  		c_can_inval_tx_object(dev, IF_TX, obj);

> >  		can_get_echo_skb(dev, idx, NULL);

> >  		bytes += priv->dlc[idx];

> > @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)

> >  	/* Clear the bits in the tx_active mask */

> >  	atomic_sub(clr, &priv->tx_active);

> >  

> > -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))

> > +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))

> 

> Do we need 1UL here, too?


Do you agree if I use the BIT macro ?

Thanks and regards
Dario

> 

> Marc

> 

> -- 

> Pengutronix e.K.                 | Marc Kleine-Budde           |

> Embedded Linux                   | https://www.pengutronix.de  |

> Vertretung West/Dortmund         | Phone: +49-231-2826-924     |

> Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Dario Binacchi March 1, 2021, 5:24 p.m. UTC | #5
Hi Marc,

> Il 01/03/2021 14:08 Marc Kleine-Budde <mkl@pengutronix.de> ha scritto:

> 

>  

> On 01.03.2021 12:38:05, Marc Kleine-Budde wrote:

> > On 28.02.2021 11:38:54, Dario Binacchi wrote:

> > [...]

> > 

> > > @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)

> > >  	while ((idx = ffs(pend))) {

> > >  		idx--;

> > >  		pend &= ~(1 << idx);

> > > -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> > > +		obj = idx + priv->msg_obj_tx_first;

> > >  		c_can_inval_tx_object(dev, IF_TX, obj);

> > >  		can_get_echo_skb(dev, idx, NULL);

> > >  		bytes += priv->dlc[idx];

> > > @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)

> > >  	/* Clear the bits in the tx_active mask */

> > >  	atomic_sub(clr, &priv->tx_active);

> > >  

> > > -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))

> > > +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))

> > 

> > Do we need 1UL here, too?

> 

> There are several more "1 <<" in the driver. As the right side of the

> sift operation can be up to 32, I think you should replace all "1 <<"

> with "1UL <<".


Do you agree if I use the BIT macro for all these shift operations?

Thanks and regards
Dario

> 

> regards,

> Marc

> 

> -- 

> Pengutronix e.K.                 | Marc Kleine-Budde           |

> Embedded Linux                   | https://www.pengutronix.de  |

> Vertretung West/Dortmund         | Phone: +49-231-2826-924     |

> Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Marc Kleine-Budde March 1, 2021, 7:45 p.m. UTC | #6
On 01.03.2021 18:21:42, Dario Binacchi wrote:
> > > @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)

> > >  	while ((idx = ffs(pend))) {

> > >  		idx--;

> > >  		pend &= ~(1 << idx);

> > > -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> > > +		obj = idx + priv->msg_obj_tx_first;

> > >  		c_can_inval_tx_object(dev, IF_TX, obj);

> > >  		can_get_echo_skb(dev, idx, NULL);

> > >  		bytes += priv->dlc[idx];

> > > @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)

> > >  	/* Clear the bits in the tx_active mask */

> > >  	atomic_sub(clr, &priv->tx_active);

> > >  

> > > -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))

> > > +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))

> > 

> > Do we need 1UL here, too?

> 

> Do you agree if I use the BIT macro ?


No, please use GENMASK(priv->msg_obj_tx_num, 0) here.

regrads,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Marc Kleine-Budde March 1, 2021, 7:46 p.m. UTC | #7
On 01.03.2021 18:24:31, Dario Binacchi wrote:
> Hi Marc,

> 

> > Il 01/03/2021 14:08 Marc Kleine-Budde <mkl@pengutronix.de> ha scritto:

> > 

> >  

> > On 01.03.2021 12:38:05, Marc Kleine-Budde wrote:

> > > On 28.02.2021 11:38:54, Dario Binacchi wrote:

> > > [...]

> > > 

> > > > @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)

> > > >  	while ((idx = ffs(pend))) {

> > > >  		idx--;

> > > >  		pend &= ~(1 << idx);

> > > > -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> > > > +		obj = idx + priv->msg_obj_tx_first;

> > > >  		c_can_inval_tx_object(dev, IF_TX, obj);

> > > >  		can_get_echo_skb(dev, idx, NULL);

> > > >  		bytes += priv->dlc[idx];

> > > > @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)

> > > >  	/* Clear the bits in the tx_active mask */

> > > >  	atomic_sub(clr, &priv->tx_active);

> > > >  

> > > > -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))

> > > > +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))

> > > 

> > > Do we need 1UL here, too?

> > 

> > There are several more "1 <<" in the driver. As the right side of the

> > sift operation can be up to 32, I think you should replace all "1 <<"

> > with "1UL <<".

> 

> Do you agree if I use the BIT macro for all these shift operations?


No, only use BIT(), where you want to set a single bit, use GENMASK()
for masks.

regards,
Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Dario Binacchi March 2, 2021, 10:50 a.m. UTC | #8
Hi Marc,

> Il 01/03/2021 20:45 Marc Kleine-Budde <mkl@pengutronix.de> ha scritto:

> 

>  

> On 01.03.2021 18:21:42, Dario Binacchi wrote:

> > > > @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)

> > > >  	while ((idx = ffs(pend))) {

> > > >  		idx--;

> > > >  		pend &= ~(1 << idx);

> > > > -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> > > > +		obj = idx + priv->msg_obj_tx_first;

> > > >  		c_can_inval_tx_object(dev, IF_TX, obj);

> > > >  		can_get_echo_skb(dev, idx, NULL);

> > > >  		bytes += priv->dlc[idx];

> > > > @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)

> > > >  	/* Clear the bits in the tx_active mask */

> > > >  	atomic_sub(clr, &priv->tx_active);

> > > >  

> > > > -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))

> > > > +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))

> > > 

> > > Do we need 1UL here, too?

> > 

> > Do you agree if I use the BIT macro ?

> 

> No, please use GENMASK(priv->msg_obj_tx_num, 0) here.

> 


In case of 64 message objects, msg_obj_tx_num = 32, and 1 << (priv->msg_obj_tx_num - 1) = 0x80000000. 
GENMASK(priv->msg_obj_tx_num, 0) = 0. 
BIT(priv->msg_obj_tx_num - 1) = 0x80000000.

Thanks and regards,
Dario

> regrads,

> Marc

> 

> -- 

> Pengutronix e.K.                 | Marc Kleine-Budde           |

> Embedded Linux                   | https://www.pengutronix.de  |

> Vertretung West/Dortmund         | Phone: +49-231-2826-924     |

> Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Marc Kleine-Budde March 2, 2021, 10:56 a.m. UTC | #9
On 3/2/21 11:50 AM, Dario Binacchi wrote:
> Hi Marc,

> 

>> Il 01/03/2021 20:45 Marc Kleine-Budde <mkl@pengutronix.de> ha scritto:

>>

>>  

>> On 01.03.2021 18:21:42, Dario Binacchi wrote:

>>>>> @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)

>>>>>  	while ((idx = ffs(pend))) {

>>>>>  		idx--;

>>>>>  		pend &= ~(1 << idx);

>>>>> -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

>>>>> +		obj = idx + priv->msg_obj_tx_first;

>>>>>  		c_can_inval_tx_object(dev, IF_TX, obj);

>>>>>  		can_get_echo_skb(dev, idx, NULL);

>>>>>  		bytes += priv->dlc[idx];

>>>>> @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)

>>>>>  	/* Clear the bits in the tx_active mask */

>>>>>  	atomic_sub(clr, &priv->tx_active);

>>>>>  

>>>>> -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))

>>>>> +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))

>>>>

>>>> Do we need 1UL here, too?

>>>

>>> Do you agree if I use the BIT macro ?

>>

>> No, please use GENMASK(priv->msg_obj_tx_num, 0) here.

> 

> In case of 64 message objects, msg_obj_tx_num = 32, and 1 << (priv->msg_obj_tx_num - 1) = 0x80000000. 

> GENMASK(priv->msg_obj_tx_num, 0) = 0. 

> BIT(priv->msg_obj_tx_num - 1) = 0x80000000.


Doh! I've misread where the -1 is places.

Marc

-- 
Pengutronix e.K.                 | Marc Kleine-Budde           |
Embedded Linux                   | https://www.pengutronix.de  |
Vertretung West/Dortmund         | Phone: +49-231-2826-924     |
Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Kurt Van Dijck March 2, 2021, 6:49 p.m. UTC | #10
On Sun, 28 Feb 2021 11:38:54 +0100, Dario Binacchi wrote:
> Date:   Sun, 28 Feb 2021 11:38:54 +0100

> From: Dario Binacchi <dariobin@libero.it>

> To: linux-kernel@vger.kernel.org

> Cc: Federico Vaga <federico.vaga@gmail.com>, Alexander Stein

>  <alexander.stein@systec-electronic.com>, Dario Binacchi

>  <dariobin@libero.it>, "David S. Miller" <davem@davemloft.net>, Jakub

>  Kicinski <kuba@kernel.org>, Marc Kleine-Budde <mkl@pengutronix.de>, Oliver

>  Hartkopp <socketcan@hartkopp.net>, Vincent Mailhol

>  <mailhol.vincent@wanadoo.fr>, Wolfgang Grandegger <wg@grandegger.com>,

>  YueHaibing <yuehaibing@huawei.com>, Zhang Qilong

>  <zhangqilong3@huawei.com>, linux-can@vger.kernel.org,

>  netdev@vger.kernel.org

> Subject: [PATCH v3 5/6] can: c_can: prepare to up the message objects number

> X-Mailer: git-send-email 2.17.1

> 

> As pointed by commit c0a9f4d396c9 ("can: c_can: Reduce register access")

> the "driver casts the 16 message objects in stone, which is completely

> braindead as contemporary hardware has up to 128 message objects".

> 

> The patch prepares the module to extend the number of message objects

> beyond the 32 currently managed. This was achieved by transforming the

> constants used to manage RX/TX messages into variables without changing

> the driver policy.

> 

> Signed-off-by: Dario Binacchi <dariobin@libero.it>

> Reported-by: kernel test robot <lkp@intel.com>

> 

> ---

> 

> Changes in v3:

> - Use unsigned int instead of int as type of the msg_obj_* fields

>   in the c_can_priv structure.

> - Replace (u64)1 with 1UL in msg_obj_rx_mask setting.

> 

> Changes in v2:

> - Fix compiling error reported by kernel test robot.

> - Add Reported-by tag.

> - Pass larger size to alloc_candev() routine to avoid an additional

>   memory allocation/deallocation.

> 

>  drivers/net/can/c_can/c_can.c          | 50 ++++++++++++++++----------

>  drivers/net/can/c_can/c_can.h          | 23 ++++++------

>  drivers/net/can/c_can/c_can_pci.c      |  2 +-

>  drivers/net/can/c_can/c_can_platform.c |  2 +-

>  4 files changed, 43 insertions(+), 34 deletions(-)

> 

> diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c

> index 7081cfaf62e2..ede6f4d62095 100644

> --- a/drivers/net/can/c_can/c_can.c

> +++ b/drivers/net/can/c_can/c_can.c

> @@ -173,9 +173,6 @@

>  /* Wait for ~1 sec for INIT bit */

>  #define INIT_WAIT_MS		1000

>  

> -/* napi related */

> -#define C_CAN_NAPI_WEIGHT	C_CAN_MSG_OBJ_RX_NUM

> -

>  /* c_can lec values */

>  enum c_can_lec_type {

>  	LEC_NO_ERROR = 0,

> @@ -325,7 +322,7 @@ static void c_can_setup_tx_object(struct net_device *dev, int iface,

>  	 * first, i.e. clear the MSGVAL flag in the arbiter.

>  	 */

>  	if (rtr != (bool)test_bit(idx, &priv->tx_dir)) {

> -		u32 obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> +		u32 obj = idx + priv->msg_obj_tx_first;

>  

>  		c_can_inval_msg_object(dev, iface, obj);

>  		change_bit(idx, &priv->tx_dir);

> @@ -463,10 +460,10 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,

>  	 * prioritized. The lowest buffer number wins.

>  	 */

>  	idx = fls(atomic_read(&priv->tx_active));

> -	obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> +	obj = idx + priv->msg_obj_tx_first;

>  

>  	/* If this is the last buffer, stop the xmit queue */

> -	if (idx == C_CAN_MSG_OBJ_TX_NUM - 1)

> +	if (idx == priv->msg_obj_tx_num - 1)

>  		netif_stop_queue(dev);

>  	/*

>  	 * Store the message in the interface so we can call

> @@ -549,17 +546,18 @@ static int c_can_set_bittiming(struct net_device *dev)

>   */

>  static void c_can_configure_msg_objects(struct net_device *dev)

>  {

> +	struct c_can_priv *priv = netdev_priv(dev);

>  	int i;

>  

>  	/* first invalidate all message objects */

> -	for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++)

> +	for (i = priv->msg_obj_rx_first; i <= priv->msg_obj_num; i++)

>  		c_can_inval_msg_object(dev, IF_RX, i);

>  

>  	/* setup receive message objects */

> -	for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++)

> +	for (i = priv->msg_obj_rx_first; i < priv->msg_obj_rx_last; i++)

>  		c_can_setup_receive_object(dev, IF_RX, i, 0, 0, IF_MCONT_RCV);

>  

> -	c_can_setup_receive_object(dev, IF_RX, C_CAN_MSG_OBJ_RX_LAST, 0, 0,

> +	c_can_setup_receive_object(dev, IF_RX, priv->msg_obj_rx_last, 0, 0,

>  				   IF_MCONT_RCV_EOB);

>  }

>  

> @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)

>  	while ((idx = ffs(pend))) {

>  		idx--;

>  		pend &= ~(1 << idx);

> -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;

> +		obj = idx + priv->msg_obj_tx_first;

>  		c_can_inval_tx_object(dev, IF_TX, obj);

>  		can_get_echo_skb(dev, idx, NULL);

>  		bytes += priv->dlc[idx];

> @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)

>  	/* Clear the bits in the tx_active mask */

>  	atomic_sub(clr, &priv->tx_active);

>  

> -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))

> +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))

>  		netif_wake_queue(dev);

>  

>  	if (pkts) {

> @@ -755,11 +753,11 @@ static void c_can_do_tx(struct net_device *dev)

>   * raced with the hardware or failed to readout all upper

>   * objects in the last run due to quota limit.

>   */

> -static u32 c_can_adjust_pending(u32 pend)

> +static u32 c_can_adjust_pending(u32 pend, u32 rx_mask)

>  {

>  	u32 weight, lasts;

>  

> -	if (pend == RECEIVE_OBJECT_BITS)

> +	if (pend == rx_mask)

>  		return pend;

>  

>  	/*

> @@ -862,8 +860,7 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota)

>  	 * It is faster to read only one 16bit register. This is only possible

>  	 * for a maximum number of 16 objects.

>  	 */

> -	BUILD_BUG_ON_MSG(C_CAN_MSG_OBJ_RX_LAST > 16,

> -			"Implementation does not support more message objects than 16");

> +	WARN_ON(priv->msg_obj_rx_last > 16);

>  

>  	while (quota > 0) {

>  		if (!pend) {

> @@ -874,7 +871,8 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota)

>  			 * If the pending field has a gap, handle the

>  			 * bits above the gap first.

>  			 */

> -			toread = c_can_adjust_pending(pend);

> +			toread = c_can_adjust_pending(pend,

> +						      priv->msg_obj_rx_mask);

>  		} else {

>  			toread = pend;

>  		}

> @@ -1205,17 +1203,31 @@ static int c_can_close(struct net_device *dev)

>  	return 0;

>  }

>  

> -struct net_device *alloc_c_can_dev(void)

> +struct net_device *alloc_c_can_dev(int msg_obj_num)

>  {

>  	struct net_device *dev;

>  	struct c_can_priv *priv;

> +	int msg_obj_tx_num = msg_obj_num / 2;


IMO, a bigger tx queue is not usefull.
A bigger rx queue however is.

My series last year took a fixed lenght of 8 for tx,
and use the remaining as rx queue.

>  

> -	dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM);

> +	dev = alloc_candev(sizeof(*priv) + sizeof(u32) * msg_obj_tx_num,

> +			   msg_obj_tx_num);

>  	if (!dev)

>  		return NULL;

>  

>  	priv = netdev_priv(dev);

> -	netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);

> +	priv->msg_obj_num = msg_obj_num;

> +	priv->msg_obj_rx_num = msg_obj_num - msg_obj_tx_num;

> +	priv->msg_obj_rx_first = 1;

> +	priv->msg_obj_rx_last =

> +		priv->msg_obj_rx_first + priv->msg_obj_rx_num - 1;

> +	priv->msg_obj_rx_mask = (1UL << priv->msg_obj_rx_num) - 1;

> +

> +	priv->msg_obj_tx_num = msg_obj_tx_num;

> +	priv->msg_obj_tx_first = priv->msg_obj_rx_last + 1;

> +	priv->msg_obj_tx_last =

> +		priv->msg_obj_tx_first + priv->msg_obj_tx_num - 1;

> +

> +	netif_napi_add(dev, &priv->napi, c_can_poll, priv->msg_obj_rx_num);

>  

>  	priv->dev = dev;

>  	priv->can.bittiming_const = &c_can_bittiming_const;

> diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h

> index 90d3d2e7a086..68295fab83d9 100644

> --- a/drivers/net/can/c_can/c_can.h

> +++ b/drivers/net/can/c_can/c_can.h

> @@ -22,18 +22,7 @@

>  #ifndef C_CAN_H

>  #define C_CAN_H

>  

> -/* message object split */

>  #define C_CAN_NO_OF_OBJECTS	32

> -#define C_CAN_MSG_OBJ_RX_NUM	16

> -#define C_CAN_MSG_OBJ_TX_NUM	16

> -

> -#define C_CAN_MSG_OBJ_RX_FIRST	1

> -#define C_CAN_MSG_OBJ_RX_LAST	(C_CAN_MSG_OBJ_RX_FIRST + \

> -				C_CAN_MSG_OBJ_RX_NUM - 1)

> -

> -#define C_CAN_MSG_OBJ_TX_FIRST	(C_CAN_MSG_OBJ_RX_LAST + 1)

> -

> -#define RECEIVE_OBJECT_BITS	0x0000ffff

>  

>  enum reg {

>  	C_CAN_CTRL_REG = 0,

> @@ -193,6 +182,14 @@ struct c_can_priv {

>  	struct napi_struct napi;

>  	struct net_device *dev;

>  	struct device *device;

> +	unsigned int msg_obj_num;

> +	unsigned int msg_obj_rx_num;

> +	unsigned int msg_obj_tx_num;

> +	unsigned int msg_obj_rx_first;

> +	unsigned int msg_obj_rx_last;

> +	unsigned int msg_obj_tx_first;

> +	unsigned int msg_obj_tx_last;

> +	u32 msg_obj_rx_mask;

>  	atomic_t tx_active;

>  	atomic_t sie_pending;

>  	unsigned long tx_dir;

> @@ -209,10 +206,10 @@ struct c_can_priv {

>  	void (*raminit) (const struct c_can_priv *priv, bool enable);

>  	u32 comm_rcv_high;

>  	u32 rxmasked;

> -	u32 dlc[C_CAN_MSG_OBJ_TX_NUM];

> +	u32 dlc[];

>  };

>  

> -struct net_device *alloc_c_can_dev(void);

> +struct net_device *alloc_c_can_dev(int msg_obj_num);

>  void free_c_can_dev(struct net_device *dev);

>  int register_c_can_dev(struct net_device *dev);

>  void unregister_c_can_dev(struct net_device *dev);

> diff --git a/drivers/net/can/c_can/c_can_pci.c b/drivers/net/can/c_can/c_can_pci.c

> index 406b4847e5dc..3752f68d095e 100644

> --- a/drivers/net/can/c_can/c_can_pci.c

> +++ b/drivers/net/can/c_can/c_can_pci.c

> @@ -149,7 +149,7 @@ static int c_can_pci_probe(struct pci_dev *pdev,

>  	}

>  

>  	/* allocate the c_can device */

> -	dev = alloc_c_can_dev();

> +	dev = alloc_c_can_dev(C_CAN_NO_OF_OBJECTS);

>  	if (!dev) {

>  		ret = -ENOMEM;

>  		goto out_iounmap;

> diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c

> index 05f425ceb53a..a5b9b1a93702 100644

> --- a/drivers/net/can/c_can/c_can_platform.c

> +++ b/drivers/net/can/c_can/c_can_platform.c

> @@ -293,7 +293,7 @@ static int c_can_plat_probe(struct platform_device *pdev)

>  	}

>  

>  	/* allocate the c_can device */

> -	dev = alloc_c_can_dev();

> +	dev = alloc_c_can_dev(C_CAN_NO_OF_OBJECTS);

>  	if (!dev) {

>  		ret = -ENOMEM;

>  		goto exit;

> -- 

> 2.17.1

>
Dario Binacchi March 3, 2021, 8:23 a.m. UTC | #11
Hi Kurt,

> Il 02/03/2021 19:49 Kurt Van Dijck <dev.kurt@vandijck-laurijssen.be> ha scritto:
> 
>  
> On Sun, 28 Feb 2021 11:38:54 +0100, Dario Binacchi wrote:
> > Date:   Sun, 28 Feb 2021 11:38:54 +0100
> > From: Dario Binacchi <dariobin@libero.it>
> > To: linux-kernel@vger.kernel.org
> > Cc: Federico Vaga <federico.vaga@gmail.com>, Alexander Stein
> >  <alexander.stein@systec-electronic.com>, Dario Binacchi
> >  <dariobin@libero.it>, "David S. Miller" <davem@davemloft.net>, Jakub
> >  Kicinski <kuba@kernel.org>, Marc Kleine-Budde <mkl@pengutronix.de>, Oliver
> >  Hartkopp <socketcan@hartkopp.net>, Vincent Mailhol
> >  <mailhol.vincent@wanadoo.fr>, Wolfgang Grandegger <wg@grandegger.com>,
> >  YueHaibing <yuehaibing@huawei.com>, Zhang Qilong
> >  <zhangqilong3@huawei.com>, linux-can@vger.kernel.org,
> >  netdev@vger.kernel.org
> > Subject: [PATCH v3 5/6] can: c_can: prepare to up the message objects number
> > X-Mailer: git-send-email 2.17.1
> > 
> > As pointed by commit c0a9f4d396c9 ("can: c_can: Reduce register access")
> > the "driver casts the 16 message objects in stone, which is completely
> > braindead as contemporary hardware has up to 128 message objects".
> > 
> > The patch prepares the module to extend the number of message objects
> > beyond the 32 currently managed. This was achieved by transforming the
> > constants used to manage RX/TX messages into variables without changing
> > the driver policy.
> > 
> > Signed-off-by: Dario Binacchi <dariobin@libero.it>
> > Reported-by: kernel test robot <lkp@intel.com>
> > 
> > ---
> > 
> > Changes in v3:
> > - Use unsigned int instead of int as type of the msg_obj_* fields
> >   in the c_can_priv structure.
> > - Replace (u64)1 with 1UL in msg_obj_rx_mask setting.
> > 
> > Changes in v2:
> > - Fix compiling error reported by kernel test robot.
> > - Add Reported-by tag.
> > - Pass larger size to alloc_candev() routine to avoid an additional
> >   memory allocation/deallocation.
> > 
> >  drivers/net/can/c_can/c_can.c          | 50 ++++++++++++++++----------
> >  drivers/net/can/c_can/c_can.h          | 23 ++++++------
> >  drivers/net/can/c_can/c_can_pci.c      |  2 +-
> >  drivers/net/can/c_can/c_can_platform.c |  2 +-
> >  4 files changed, 43 insertions(+), 34 deletions(-)
> > 
> > diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
> > index 7081cfaf62e2..ede6f4d62095 100644
> > --- a/drivers/net/can/c_can/c_can.c
> > +++ b/drivers/net/can/c_can/c_can.c
> > @@ -173,9 +173,6 @@
> >  /* Wait for ~1 sec for INIT bit */
> >  #define INIT_WAIT_MS		1000
> >  
> > -/* napi related */
> > -#define C_CAN_NAPI_WEIGHT	C_CAN_MSG_OBJ_RX_NUM
> > -
> >  /* c_can lec values */
> >  enum c_can_lec_type {
> >  	LEC_NO_ERROR = 0,
> > @@ -325,7 +322,7 @@ static void c_can_setup_tx_object(struct net_device *dev, int iface,
> >  	 * first, i.e. clear the MSGVAL flag in the arbiter.
> >  	 */
> >  	if (rtr != (bool)test_bit(idx, &priv->tx_dir)) {
> > -		u32 obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
> > +		u32 obj = idx + priv->msg_obj_tx_first;
> >  
> >  		c_can_inval_msg_object(dev, iface, obj);
> >  		change_bit(idx, &priv->tx_dir);
> > @@ -463,10 +460,10 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
> >  	 * prioritized. The lowest buffer number wins.
> >  	 */
> >  	idx = fls(atomic_read(&priv->tx_active));
> > -	obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
> > +	obj = idx + priv->msg_obj_tx_first;
> >  
> >  	/* If this is the last buffer, stop the xmit queue */
> > -	if (idx == C_CAN_MSG_OBJ_TX_NUM - 1)
> > +	if (idx == priv->msg_obj_tx_num - 1)
> >  		netif_stop_queue(dev);
> >  	/*
> >  	 * Store the message in the interface so we can call
> > @@ -549,17 +546,18 @@ static int c_can_set_bittiming(struct net_device *dev)
> >   */
> >  static void c_can_configure_msg_objects(struct net_device *dev)
> >  {
> > +	struct c_can_priv *priv = netdev_priv(dev);
> >  	int i;
> >  
> >  	/* first invalidate all message objects */
> > -	for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++)
> > +	for (i = priv->msg_obj_rx_first; i <= priv->msg_obj_num; i++)
> >  		c_can_inval_msg_object(dev, IF_RX, i);
> >  
> >  	/* setup receive message objects */
> > -	for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++)
> > +	for (i = priv->msg_obj_rx_first; i < priv->msg_obj_rx_last; i++)
> >  		c_can_setup_receive_object(dev, IF_RX, i, 0, 0, IF_MCONT_RCV);
> >  
> > -	c_can_setup_receive_object(dev, IF_RX, C_CAN_MSG_OBJ_RX_LAST, 0, 0,
> > +	c_can_setup_receive_object(dev, IF_RX, priv->msg_obj_rx_last, 0, 0,
> >  				   IF_MCONT_RCV_EOB);
> >  }
> >  
> > @@ -730,7 +728,7 @@ static void c_can_do_tx(struct net_device *dev)
> >  	while ((idx = ffs(pend))) {
> >  		idx--;
> >  		pend &= ~(1 << idx);
> > -		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
> > +		obj = idx + priv->msg_obj_tx_first;
> >  		c_can_inval_tx_object(dev, IF_TX, obj);
> >  		can_get_echo_skb(dev, idx, NULL);
> >  		bytes += priv->dlc[idx];
> > @@ -740,7 +738,7 @@ static void c_can_do_tx(struct net_device *dev)
> >  	/* Clear the bits in the tx_active mask */
> >  	atomic_sub(clr, &priv->tx_active);
> >  
> > -	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))
> > +	if (clr & (1 << (priv->msg_obj_tx_num - 1)))
> >  		netif_wake_queue(dev);
> >  
> >  	if (pkts) {
> > @@ -755,11 +753,11 @@ static void c_can_do_tx(struct net_device *dev)
> >   * raced with the hardware or failed to readout all upper
> >   * objects in the last run due to quota limit.
> >   */
> > -static u32 c_can_adjust_pending(u32 pend)
> > +static u32 c_can_adjust_pending(u32 pend, u32 rx_mask)
> >  {
> >  	u32 weight, lasts;
> >  
> > -	if (pend == RECEIVE_OBJECT_BITS)
> > +	if (pend == rx_mask)
> >  		return pend;
> >  
> >  	/*
> > @@ -862,8 +860,7 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota)
> >  	 * It is faster to read only one 16bit register. This is only possible
> >  	 * for a maximum number of 16 objects.
> >  	 */
> > -	BUILD_BUG_ON_MSG(C_CAN_MSG_OBJ_RX_LAST > 16,
> > -			"Implementation does not support more message objects than 16");
> > +	WARN_ON(priv->msg_obj_rx_last > 16);
> >  
> >  	while (quota > 0) {
> >  		if (!pend) {
> > @@ -874,7 +871,8 @@ static int c_can_do_rx_poll(struct net_device *dev, int quota)
> >  			 * If the pending field has a gap, handle the
> >  			 * bits above the gap first.
> >  			 */
> > -			toread = c_can_adjust_pending(pend);
> > +			toread = c_can_adjust_pending(pend,
> > +						      priv->msg_obj_rx_mask);
> >  		} else {
> >  			toread = pend;
> >  		}
> > @@ -1205,17 +1203,31 @@ static int c_can_close(struct net_device *dev)
> >  	return 0;
> >  }
> >  
> > -struct net_device *alloc_c_can_dev(void)
> > +struct net_device *alloc_c_can_dev(int msg_obj_num)
> >  {
> >  	struct net_device *dev;
> >  	struct c_can_priv *priv;
> > +	int msg_obj_tx_num = msg_obj_num / 2;
> 
> IMO, a bigger tx queue is not usefull.
> A bigger rx queue however is.

This would not be good for my application. 
I think it really depends on the type of application. 
We can probably say that being able to size rx/tx queue
would be a useful feature.

Thanks and regards,
Dario

> 
> My series last year took a fixed lenght of 8 for tx,
> and use the remaining as rx queue.
> 
> >  
> > -	dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM);
> > +	dev = alloc_candev(sizeof(*priv) + sizeof(u32) * msg_obj_tx_num,
> > +			   msg_obj_tx_num);
> >  	if (!dev)
> >  		return NULL;
> >  
> >  	priv = netdev_priv(dev);
> > -	netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
> > +	priv->msg_obj_num = msg_obj_num;
> > +	priv->msg_obj_rx_num = msg_obj_num - msg_obj_tx_num;
> > +	priv->msg_obj_rx_first = 1;
> > +	priv->msg_obj_rx_last =
> > +		priv->msg_obj_rx_first + priv->msg_obj_rx_num - 1;
> > +	priv->msg_obj_rx_mask = (1UL << priv->msg_obj_rx_num) - 1;
> > +
> > +	priv->msg_obj_tx_num = msg_obj_tx_num;
> > +	priv->msg_obj_tx_first = priv->msg_obj_rx_last + 1;
> > +	priv->msg_obj_tx_last =
> > +		priv->msg_obj_tx_first + priv->msg_obj_tx_num - 1;
> > +
> > +	netif_napi_add(dev, &priv->napi, c_can_poll, priv->msg_obj_rx_num);
> >  
> >  	priv->dev = dev;
> >  	priv->can.bittiming_const = &c_can_bittiming_const;
> > diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
> > index 90d3d2e7a086..68295fab83d9 100644
> > --- a/drivers/net/can/c_can/c_can.h
> > +++ b/drivers/net/can/c_can/c_can.h
> > @@ -22,18 +22,7 @@
> >  #ifndef C_CAN_H
> >  #define C_CAN_H
> >  
> > -/* message object split */
> >  #define C_CAN_NO_OF_OBJECTS	32
> > -#define C_CAN_MSG_OBJ_RX_NUM	16
> > -#define C_CAN_MSG_OBJ_TX_NUM	16
> > -
> > -#define C_CAN_MSG_OBJ_RX_FIRST	1
> > -#define C_CAN_MSG_OBJ_RX_LAST	(C_CAN_MSG_OBJ_RX_FIRST + \
> > -				C_CAN_MSG_OBJ_RX_NUM - 1)
> > -
> > -#define C_CAN_MSG_OBJ_TX_FIRST	(C_CAN_MSG_OBJ_RX_LAST + 1)
> > -
> > -#define RECEIVE_OBJECT_BITS	0x0000ffff
> >  
> >  enum reg {
> >  	C_CAN_CTRL_REG = 0,
> > @@ -193,6 +182,14 @@ struct c_can_priv {
> >  	struct napi_struct napi;
> >  	struct net_device *dev;
> >  	struct device *device;
> > +	unsigned int msg_obj_num;
> > +	unsigned int msg_obj_rx_num;
> > +	unsigned int msg_obj_tx_num;
> > +	unsigned int msg_obj_rx_first;
> > +	unsigned int msg_obj_rx_last;
> > +	unsigned int msg_obj_tx_first;
> > +	unsigned int msg_obj_tx_last;
> > +	u32 msg_obj_rx_mask;
> >  	atomic_t tx_active;
> >  	atomic_t sie_pending;
> >  	unsigned long tx_dir;
> > @@ -209,10 +206,10 @@ struct c_can_priv {
> >  	void (*raminit) (const struct c_can_priv *priv, bool enable);
> >  	u32 comm_rcv_high;
> >  	u32 rxmasked;
> > -	u32 dlc[C_CAN_MSG_OBJ_TX_NUM];
> > +	u32 dlc[];
> >  };
> >  
> > -struct net_device *alloc_c_can_dev(void);
> > +struct net_device *alloc_c_can_dev(int msg_obj_num);
> >  void free_c_can_dev(struct net_device *dev);
> >  int register_c_can_dev(struct net_device *dev);
> >  void unregister_c_can_dev(struct net_device *dev);
> > diff --git a/drivers/net/can/c_can/c_can_pci.c b/drivers/net/can/c_can/c_can_pci.c
> > index 406b4847e5dc..3752f68d095e 100644
> > --- a/drivers/net/can/c_can/c_can_pci.c
> > +++ b/drivers/net/can/c_can/c_can_pci.c
> > @@ -149,7 +149,7 @@ static int c_can_pci_probe(struct pci_dev *pdev,
> >  	}
> >  
> >  	/* allocate the c_can device */
> > -	dev = alloc_c_can_dev();
> > +	dev = alloc_c_can_dev(C_CAN_NO_OF_OBJECTS);
> >  	if (!dev) {
> >  		ret = -ENOMEM;
> >  		goto out_iounmap;
> > diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c
> > index 05f425ceb53a..a5b9b1a93702 100644
> > --- a/drivers/net/can/c_can/c_can_platform.c
> > +++ b/drivers/net/can/c_can/c_can_platform.c
> > @@ -293,7 +293,7 @@ static int c_can_plat_probe(struct platform_device *pdev)
> >  	}
> >  
> >  	/* allocate the c_can device */
> > -	dev = alloc_c_can_dev();
> > +	dev = alloc_c_can_dev(C_CAN_NO_OF_OBJECTS);
> >  	if (!dev) {
> >  		ret = -ENOMEM;
> >  		goto exit;
> > -- 
> > 2.17.1
> >
Marc Kleine-Budde March 3, 2021, 9 a.m. UTC | #12
On 03.03.2021 09:23:13, Dario Binacchi wrote:
[...]
> > > @@ -1205,17 +1203,31 @@ static int c_can_close(struct net_device *dev)
> > >  	return 0;
> > >  }
> > >  
> > > -struct net_device *alloc_c_can_dev(void)
> > > +struct net_device *alloc_c_can_dev(int msg_obj_num)
> > >  {
> > >  	struct net_device *dev;
> > >  	struct c_can_priv *priv;
> > > +	int msg_obj_tx_num = msg_obj_num / 2;
> > 
> > IMO, a bigger tx queue is not usefull.
> > A bigger rx queue however is.
> 
> This would not be good for my application. I think it really depends
> on the type of application. We can probably say that being able to
> size rx/tx queue would be a useful feature.

Ok. There is an ethtool interface to configure the size of the RX and TX
queues. In ethtool it's called the RX/TX "ring" size and you can get it
via the -g parameter, e.g. here for by Ethernet interface:

| $ ethtool -g enp0s25
| Ring parameters for enp0s25:
| Pre-set maximums:
| RX:		4096
| RX Mini:	n/a
| RX Jumbo:	n/a
| TX:		4096
| Current hardware settings:
| RX:		256
| RX Mini:	n/a
| RX Jumbo:	n/a
| TX:		256

If I understand correctly patch 6 has some assumptions that RX and TX
are max 32. To support up to 64 RX objects, you have to convert:
- u32 -> u64
- BIT() -> BIT_ULL()
- GENMASK() -> GENMASK_ULL()

The register access has to be converted, too. For performance reasons
you want to do as least as possible. Which is probably the most
complicated.

In the flexcan driver I have a similar problem. The driver keeps masks,
which mailboxes are RX and which TX and I added wrapper functions to
minimize IO access:

https://elixir.bootlin.com/linux/v5.11/source/drivers/net/can/flexcan.c#L904

This should to IMHO into patch 6.

Adding the ethtool support and making the rings configurable would be a
separate patch.

regards,
Marc
Dario Binacchi March 3, 2021, 10:31 a.m. UTC | #13
Hi Marc,

> Il 03/03/2021 10:00 Marc Kleine-Budde <mkl@pengutronix.de> ha scritto:

> 

>  

> On 03.03.2021 09:23:13, Dario Binacchi wrote:

> [...]

> > > > @@ -1205,17 +1203,31 @@ static int c_can_close(struct net_device *dev)

> > > >  	return 0;

> > > >  }

> > > >  

> > > > -struct net_device *alloc_c_can_dev(void)

> > > > +struct net_device *alloc_c_can_dev(int msg_obj_num)

> > > >  {

> > > >  	struct net_device *dev;

> > > >  	struct c_can_priv *priv;

> > > > +	int msg_obj_tx_num = msg_obj_num / 2;

> > > 

> > > IMO, a bigger tx queue is not usefull.

> > > A bigger rx queue however is.

> > 

> > This would not be good for my application. I think it really depends

> > on the type of application. We can probably say that being able to

> > size rx/tx queue would be a useful feature.

> 

> Ok. There is an ethtool interface to configure the size of the RX and TX

> queues. In ethtool it's called the RX/TX "ring" size and you can get it

> via the -g parameter, e.g. here for by Ethernet interface:

> 

> | $ ethtool -g enp0s25

> | Ring parameters for enp0s25:

> | Pre-set maximums:

> | RX:		4096

> | RX Mini:	n/a

> | RX Jumbo:	n/a

> | TX:		4096

> | Current hardware settings:

> | RX:		256

> | RX Mini:	n/a

> | RX Jumbo:	n/a

> | TX:		256

> 

> If I understand correctly patch 6 has some assumptions that RX and TX

> are max 32. To support up to 64 RX objects, you have to convert:

> - u32 -> u64

> - BIT() -> BIT_ULL()

> - GENMASK() -> GENMASK_ULL()

> 

> The register access has to be converted, too. For performance reasons

> you want to do as least as possible. Which is probably the most

> complicated.

> 

> In the flexcan driver I have a similar problem. The driver keeps masks,

> which mailboxes are RX and which TX and I added wrapper functions to

> minimize IO access:

> 

> https://elixir.bootlin.com/linux/v5.11/source/drivers/net/can/flexcan.c#L904

> 

> This should to IMHO into patch 6.

> 

> Adding the ethtool support and making the rings configurable would be a

> separate patch.

> 


I think these features need to be developed in a later series. 
I would stay with the extension to 64 messages equally divided 
between reception and transmission.

Thanks and regards,
Dario

> regards,

> Marc

> 

> -- 

> Pengutronix e.K.                 | Marc Kleine-Budde           |

> Embedded Linux                   | https://www.pengutronix.de  |

> Vertretung West/Dortmund         | Phone: +49-231-2826-924     |

> Amtsgericht Hildesheim, HRA 2686 | Fax:   +49-5121-206917-5555 |
Marc Kleine-Budde March 3, 2021, 10:36 a.m. UTC | #14
On 03.03.2021 11:31:10, Dario Binacchi wrote:
> I think these features need to be developed in a later series. 
> I would stay with the extension to 64 messages equally divided 
> between reception and transmission.

Fine with me.

Marc
diff mbox series

Patch

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index 7081cfaf62e2..ede6f4d62095 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -173,9 +173,6 @@ 
 /* Wait for ~1 sec for INIT bit */
 #define INIT_WAIT_MS		1000
 
-/* napi related */
-#define C_CAN_NAPI_WEIGHT	C_CAN_MSG_OBJ_RX_NUM
-
 /* c_can lec values */
 enum c_can_lec_type {
 	LEC_NO_ERROR = 0,
@@ -325,7 +322,7 @@  static void c_can_setup_tx_object(struct net_device *dev, int iface,
 	 * first, i.e. clear the MSGVAL flag in the arbiter.
 	 */
 	if (rtr != (bool)test_bit(idx, &priv->tx_dir)) {
-		u32 obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
+		u32 obj = idx + priv->msg_obj_tx_first;
 
 		c_can_inval_msg_object(dev, iface, obj);
 		change_bit(idx, &priv->tx_dir);
@@ -463,10 +460,10 @@  static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
 	 * prioritized. The lowest buffer number wins.
 	 */
 	idx = fls(atomic_read(&priv->tx_active));
-	obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
+	obj = idx + priv->msg_obj_tx_first;
 
 	/* If this is the last buffer, stop the xmit queue */
-	if (idx == C_CAN_MSG_OBJ_TX_NUM - 1)
+	if (idx == priv->msg_obj_tx_num - 1)
 		netif_stop_queue(dev);
 	/*
 	 * Store the message in the interface so we can call
@@ -549,17 +546,18 @@  static int c_can_set_bittiming(struct net_device *dev)
  */
 static void c_can_configure_msg_objects(struct net_device *dev)
 {
+	struct c_can_priv *priv = netdev_priv(dev);
 	int i;
 
 	/* first invalidate all message objects */
-	for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++)
+	for (i = priv->msg_obj_rx_first; i <= priv->msg_obj_num; i++)
 		c_can_inval_msg_object(dev, IF_RX, i);
 
 	/* setup receive message objects */
-	for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++)
+	for (i = priv->msg_obj_rx_first; i < priv->msg_obj_rx_last; i++)
 		c_can_setup_receive_object(dev, IF_RX, i, 0, 0, IF_MCONT_RCV);
 
-	c_can_setup_receive_object(dev, IF_RX, C_CAN_MSG_OBJ_RX_LAST, 0, 0,
+	c_can_setup_receive_object(dev, IF_RX, priv->msg_obj_rx_last, 0, 0,
 				   IF_MCONT_RCV_EOB);
 }
 
@@ -730,7 +728,7 @@  static void c_can_do_tx(struct net_device *dev)
 	while ((idx = ffs(pend))) {
 		idx--;
 		pend &= ~(1 << idx);
-		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
+		obj = idx + priv->msg_obj_tx_first;
 		c_can_inval_tx_object(dev, IF_TX, obj);
 		can_get_echo_skb(dev, idx, NULL);
 		bytes += priv->dlc[idx];
@@ -740,7 +738,7 @@  static void c_can_do_tx(struct net_device *dev)
 	/* Clear the bits in the tx_active mask */
 	atomic_sub(clr, &priv->tx_active);
 
-	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))
+	if (clr & (1 << (priv->msg_obj_tx_num - 1)))
 		netif_wake_queue(dev);
 
 	if (pkts) {
@@ -755,11 +753,11 @@  static void c_can_do_tx(struct net_device *dev)
  * raced with the hardware or failed to readout all upper
  * objects in the last run due to quota limit.
  */
-static u32 c_can_adjust_pending(u32 pend)
+static u32 c_can_adjust_pending(u32 pend, u32 rx_mask)
 {
 	u32 weight, lasts;
 
-	if (pend == RECEIVE_OBJECT_BITS)
+	if (pend == rx_mask)
 		return pend;
 
 	/*
@@ -862,8 +860,7 @@  static int c_can_do_rx_poll(struct net_device *dev, int quota)
 	 * It is faster to read only one 16bit register. This is only possible
 	 * for a maximum number of 16 objects.
 	 */
-	BUILD_BUG_ON_MSG(C_CAN_MSG_OBJ_RX_LAST > 16,
-			"Implementation does not support more message objects than 16");
+	WARN_ON(priv->msg_obj_rx_last > 16);
 
 	while (quota > 0) {
 		if (!pend) {
@@ -874,7 +871,8 @@  static int c_can_do_rx_poll(struct net_device *dev, int quota)
 			 * If the pending field has a gap, handle the
 			 * bits above the gap first.
 			 */
-			toread = c_can_adjust_pending(pend);
+			toread = c_can_adjust_pending(pend,
+						      priv->msg_obj_rx_mask);
 		} else {
 			toread = pend;
 		}
@@ -1205,17 +1203,31 @@  static int c_can_close(struct net_device *dev)
 	return 0;
 }
 
-struct net_device *alloc_c_can_dev(void)
+struct net_device *alloc_c_can_dev(int msg_obj_num)
 {
 	struct net_device *dev;
 	struct c_can_priv *priv;
+	int msg_obj_tx_num = msg_obj_num / 2;
 
-	dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM);
+	dev = alloc_candev(sizeof(*priv) + sizeof(u32) * msg_obj_tx_num,
+			   msg_obj_tx_num);
 	if (!dev)
 		return NULL;
 
 	priv = netdev_priv(dev);
-	netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
+	priv->msg_obj_num = msg_obj_num;
+	priv->msg_obj_rx_num = msg_obj_num - msg_obj_tx_num;
+	priv->msg_obj_rx_first = 1;
+	priv->msg_obj_rx_last =
+		priv->msg_obj_rx_first + priv->msg_obj_rx_num - 1;
+	priv->msg_obj_rx_mask = (1UL << priv->msg_obj_rx_num) - 1;
+
+	priv->msg_obj_tx_num = msg_obj_tx_num;
+	priv->msg_obj_tx_first = priv->msg_obj_rx_last + 1;
+	priv->msg_obj_tx_last =
+		priv->msg_obj_tx_first + priv->msg_obj_tx_num - 1;
+
+	netif_napi_add(dev, &priv->napi, c_can_poll, priv->msg_obj_rx_num);
 
 	priv->dev = dev;
 	priv->can.bittiming_const = &c_can_bittiming_const;
diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
index 90d3d2e7a086..68295fab83d9 100644
--- a/drivers/net/can/c_can/c_can.h
+++ b/drivers/net/can/c_can/c_can.h
@@ -22,18 +22,7 @@ 
 #ifndef C_CAN_H
 #define C_CAN_H
 
-/* message object split */
 #define C_CAN_NO_OF_OBJECTS	32
-#define C_CAN_MSG_OBJ_RX_NUM	16
-#define C_CAN_MSG_OBJ_TX_NUM	16
-
-#define C_CAN_MSG_OBJ_RX_FIRST	1
-#define C_CAN_MSG_OBJ_RX_LAST	(C_CAN_MSG_OBJ_RX_FIRST + \
-				C_CAN_MSG_OBJ_RX_NUM - 1)
-
-#define C_CAN_MSG_OBJ_TX_FIRST	(C_CAN_MSG_OBJ_RX_LAST + 1)
-
-#define RECEIVE_OBJECT_BITS	0x0000ffff
 
 enum reg {
 	C_CAN_CTRL_REG = 0,
@@ -193,6 +182,14 @@  struct c_can_priv {
 	struct napi_struct napi;
 	struct net_device *dev;
 	struct device *device;
+	unsigned int msg_obj_num;
+	unsigned int msg_obj_rx_num;
+	unsigned int msg_obj_tx_num;
+	unsigned int msg_obj_rx_first;
+	unsigned int msg_obj_rx_last;
+	unsigned int msg_obj_tx_first;
+	unsigned int msg_obj_tx_last;
+	u32 msg_obj_rx_mask;
 	atomic_t tx_active;
 	atomic_t sie_pending;
 	unsigned long tx_dir;
@@ -209,10 +206,10 @@  struct c_can_priv {
 	void (*raminit) (const struct c_can_priv *priv, bool enable);
 	u32 comm_rcv_high;
 	u32 rxmasked;
-	u32 dlc[C_CAN_MSG_OBJ_TX_NUM];
+	u32 dlc[];
 };
 
-struct net_device *alloc_c_can_dev(void);
+struct net_device *alloc_c_can_dev(int msg_obj_num);
 void free_c_can_dev(struct net_device *dev);
 int register_c_can_dev(struct net_device *dev);
 void unregister_c_can_dev(struct net_device *dev);
diff --git a/drivers/net/can/c_can/c_can_pci.c b/drivers/net/can/c_can/c_can_pci.c
index 406b4847e5dc..3752f68d095e 100644
--- a/drivers/net/can/c_can/c_can_pci.c
+++ b/drivers/net/can/c_can/c_can_pci.c
@@ -149,7 +149,7 @@  static int c_can_pci_probe(struct pci_dev *pdev,
 	}
 
 	/* allocate the c_can device */
-	dev = alloc_c_can_dev();
+	dev = alloc_c_can_dev(C_CAN_NO_OF_OBJECTS);
 	if (!dev) {
 		ret = -ENOMEM;
 		goto out_iounmap;
diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c
index 05f425ceb53a..a5b9b1a93702 100644
--- a/drivers/net/can/c_can/c_can_platform.c
+++ b/drivers/net/can/c_can/c_can_platform.c
@@ -293,7 +293,7 @@  static int c_can_plat_probe(struct platform_device *pdev)
 	}
 
 	/* allocate the c_can device */
-	dev = alloc_c_can_dev();
+	dev = alloc_c_can_dev(C_CAN_NO_OF_OBJECTS);
 	if (!dev) {
 		ret = -ENOMEM;
 		goto exit;