diff mbox

[v6,1/2] Mailbox: Add support for Platform Communication Channel

Message ID 1409856561-3945-2-git-send-email-ashwin.chaugule@linaro.org
State New
Headers show

Commit Message

Ashwin Chaugule Sept. 4, 2014, 6:49 p.m. UTC 
ACPI 5.0+ spec defines a generic mode of communication
between the OS and a platform such as the BMC. This medium
(PCC) is typically used by CPPC (ACPI CPU Performance management),
RAS (ACPI reliability protocol) and MPST (ACPI Memory power
states).

This patch adds PCC support as a Mailbox Controller.

Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
---
 drivers/mailbox/Kconfig   |  12 ++
 drivers/mailbox/Makefile  |   2 +
 drivers/mailbox/mailbox.c |   4 +-
 drivers/mailbox/mailbox.h |  16 +++
 drivers/mailbox/pcc.c     | 279 ++++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 310 insertions(+), 3 deletions(-)
 create mode 100644 drivers/mailbox/mailbox.h
 create mode 100644 drivers/mailbox/pcc.c

Comments

Zheng, Lv Sept. 5, 2014, 1:56 a.m. UTC | #1 
Hi,

> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-owner@vger.kernel.org] On Behalf Of Ashwin Chaugule
> Sent: Friday, September 05, 2014 2:49 AM
> 
> ACPI 5.0+ spec defines a generic mode of communication
> between the OS and a platform such as the BMC. This medium
> (PCC) is typically used by CPPC (ACPI CPU Performance management),
> RAS (ACPI reliability protocol) and MPST (ACPI Memory power
> states).
> 
> This patch adds PCC support as a Mailbox Controller.
> 
> Signed-off-by: Ashwin Chaugule <ashwin.chaugule@linaro.org>
> ---
>  drivers/mailbox/Kconfig   |  12 ++
>  drivers/mailbox/Makefile  |   2 +
>  drivers/mailbox/mailbox.c |   4 +-
>  drivers/mailbox/mailbox.h |  16 +++
>  drivers/mailbox/pcc.c     | 279 ++++++++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 310 insertions(+), 3 deletions(-)
>  create mode 100644 drivers/mailbox/mailbox.h
>  create mode 100644 drivers/mailbox/pcc.c
> 
> diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
> index c8b5c13..e08cc83 100644
> --- a/drivers/mailbox/Kconfig
> +++ b/drivers/mailbox/Kconfig
> @@ -50,4 +50,16 @@ config OMAP_MBOX_KFIFO_SIZE
>  	  Specify the default size of mailbox's kfifo buffers (bytes).
>  	  This can also be changed at runtime (via the mbox_kfifo_size
>  	  module parameter).
> +
> +config PCC
> +	bool "Platform Communication Channel Driver"
> +	depends on ACPI
> +	help
> +		ACPI 5.0+ spec defines a generic mode of communication
> +		between the OS and a platform such as the BMC. This medium
> +		(PCC) is typically used by CPPC (ACPI CPU Performance management),
> +		RAS (ACPI reliability protocol) and MPST (ACPI Memory power
> +		states). Select this driver if your platform implements the
> +		PCC clients mentioned above.
> +
>  endif
> diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
> index 2fa343a..0b09d6f 100644
> --- a/drivers/mailbox/Makefile
> +++ b/drivers/mailbox/Makefile
> @@ -9,3 +9,5 @@ obj-$(CONFIG_OMAP1_MBOX)	+= mailbox_omap1.o
>  mailbox_omap1-objs		:= mailbox-omap1.o
>  obj-$(CONFIG_OMAP2PLUS_MBOX)	+= mailbox_omap2.o
>  mailbox_omap2-objs		:= mailbox-omap2.o
> +
> +obj-$(CONFIG_PCC)			+= pcc.o
> diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
> index 63ecc17..9d9366a 100644
> --- a/drivers/mailbox/mailbox.c
> +++ b/drivers/mailbox/mailbox.c
> @@ -21,9 +21,7 @@
>  #include <linux/mailbox_client.h>
>  #include <linux/mailbox_controller.h>
> 
> -#define TXDONE_BY_IRQ	BIT(0) /* controller has remote RTR irq */
> -#define TXDONE_BY_POLL	BIT(1) /* controller can read status of last TX */
> -#define TXDONE_BY_ACK	BIT(2) /* S/W ACK recevied by Client ticks the TX */
> +#include "mailbox.h"
> 
>  static LIST_HEAD(mbox_cons);
>  static DEFINE_MUTEX(con_mutex);
> diff --git a/drivers/mailbox/mailbox.h b/drivers/mailbox/mailbox.h
> new file mode 100644
> index 0000000..5a15a25
> --- /dev/null
> +++ b/drivers/mailbox/mailbox.h
> @@ -0,0 +1,16 @@
> +/*
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + */
> +
> +#ifndef __MAILBOX_H
> +#define __MAILBOX_H
> +
> +#define TXDONE_BY_IRQ	BIT(0) /* controller has remote RTR irq */
> +#define TXDONE_BY_POLL	BIT(1) /* controller can read status of last TX */
> +#define TXDONE_BY_ACK	BIT(2) /* S/W ACK recevied by Client ticks the TX */
> +
> +#endif /* __MAILBOX_H */
> +
> +
> diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
> new file mode 100644
> index 0000000..7831a01
> --- /dev/null
> +++ b/drivers/mailbox/pcc.c
> @@ -0,0 +1,279 @@
> +/*
> + *	Copyright (C) 2014 Linaro Ltd.
> + *	Author:	Ashwin Chaugule <ashwin.chaugule@linaro.org>
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License as published by
> + *  the Free Software Foundation; either version 2 of the License, or
> + *  (at your option) any later version.
> + *
> + *  This program is distributed in the hope that it will be useful,
> + *  but WITHOUT ANY WARRANTY; without even the implied warranty of
> + *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + *  GNU General Public License for more details.
> + *
> + */
> +
> +#include <linux/acpi.h>
> +#include <linux/cpufreq.h>
> +#include <linux/delay.h>
> +#include <linux/io.h>
> +#include <linux/init.h>
> +#include <linux/ioctl.h>
> +#include <linux/module.h>
> +#include <linux/uaccess.h>
> +#include <linux/vmalloc.h>
> +#include <linux/platform_device.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/mailbox_client.h>
> +
> +#include "mailbox.h"
> +
> +#define MAX_PCC_SUBSPACES	256
> +#define PCCS_SS_SIG_MAGIC	0x50434300
> +#define PCC_CMD_COMPLETE	0x1
> +
> +static struct mbox_chan pcc_mbox_chan[MAX_PCC_SUBSPACES];
> +static struct mbox_controller pcc_mbox_ctrl = {};
> +
> +struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
> +		int index)
> +{
> +	struct device *dev = pcc_mbox_ctrl.dev;
> +	struct mbox_chan *chan;
> +	unsigned long flags;
> +
> +	/*
> +	 * Each PCC Subspace is a Mailbox Channel.
> +	 * The PCC Clients get their PCC Subspace ID
> +	 * from their own tables and pass it here.
> +	 * This returns a pointer to the PCC subspace
> +	 * for the Client to operate on.
> +	 */
> +	chan = &pcc_mbox_chan[index];
> +
> +	if (!chan || chan->cl) {
> +		dev_err(dev, "%s: PCC mailbox not free\n", __func__);
> +		return ERR_PTR(-EBUSY);
> +	}
> +
> +	spin_lock_irqsave(&chan->lock, flags);
> +	chan->msg_free = 0;
> +	chan->msg_count = 0;
> +	chan->active_req = NULL;
> +	chan->cl = cl;
> +	init_completion(&chan->tx_complete);
> +
> +	if (chan->txdone_method	== TXDONE_BY_POLL && cl->knows_txdone)

The tab should be a space here?

> +		chan->txdone_method |= TXDONE_BY_ACK;
> +
> +	spin_unlock_irqrestore(&chan->lock, flags);
> +
> +	return chan;
> +}
> +EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
> +
> +void pcc_mbox_free_channel(struct mbox_chan *chan)
> +{
> +	unsigned long flags;
> +
> +	if (!chan || !chan->cl)
> +		return;
> +
> +	spin_lock_irqsave(&chan->lock, flags);
> +	chan->cl = NULL;
> +	chan->active_req = NULL;
> +	if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
> +		chan->txdone_method = TXDONE_BY_POLL;
> +
> +	spin_unlock_irqrestore(&chan->lock, flags);
> +}
> +EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
> +
> +static bool pcc_tx_done(struct mbox_chan *chan)
> +{
> +	struct acpi_pcct_subspace *pcct_ss = chan->con_priv;
> +	struct acpi_pcct_shared_memory *generic_comm_base =
> +		(struct acpi_pcct_shared_memory *) pcct_ss->base_address;
> +	u16 cmd_delay = pcct_ss->min_turnaround_time;

Should these parameters be acquired with chan-lock held?
Is that possible to change them during runtime?

> +
> +	/* Wait for Platform to consume. */
> +	while (!(readw_relaxed(&generic_comm_base->status) & PCC_CMD_COMPLETE))
> +		udelay(cmd_delay);
> +
> +	return true;
> +}
> +
> +static int get_subspace_id(struct mbox_chan *chan)
> +{
> +	int id = chan - pcc_mbox_chan;
> +
> +	if (id < 0 || id > pcc_mbox_ctrl.num_chans)
> +		return -ENOENT;
> +
> +	return id;
> +}
> +
> +/* Channel lock is already held by mbox controller code. */
> +static int pcc_send_data(struct mbox_chan *chan, void *data)
> +{
> +	struct acpi_pcct_subspace *pcct_ss = chan->con_priv;
> +	struct acpi_pcct_shared_memory *generic_comm_base =
> +		(struct acpi_pcct_shared_memory *) pcct_ss->base_address;


Ditto.

> +	struct acpi_generic_address doorbell;
> +	u64 doorbell_preserve;
> +	u64 doorbell_val;
> +	u64 doorbell_write;
> +	u16 cmd = *(u16 *) data;
> +	u16 ss_idx = -1;
> +	int ret = 0;
> +
> +	ss_idx = get_subspace_id(chan);
> +
> +	if (ss_idx < 0) {
> +		pr_err("Invalid Subspace ID from PCC client\n");
> +		ret = -EINVAL;
> +		goto out_err;
> +	}
> +
> +	doorbell = pcct_ss->doorbell_register;
> +	doorbell_preserve = pcct_ss->preserve_mask;
> +	doorbell_write = pcct_ss->write_mask;
> +
> +	/* Write to the shared comm region. */
> +	writew(cmd, &generic_comm_base->command);
> +
> +	/* Write Subspace MAGIC value so platform can identify destination. */
> +	writel((PCCS_SS_SIG_MAGIC | ss_idx), &generic_comm_base->signature);
> +
> +	/* Flip CMD COMPLETE bit */
> +	writew(0, &generic_comm_base->status);
> +
> +	/* Sync notification from OSPM to Platform. */
> +	acpi_read(&doorbell_val, &doorbell);
> +	acpi_write((doorbell_val & doorbell_preserve) | doorbell_write,
> +			&doorbell);
> +
> +out_err:
> +	return ret;
> +}
> +
> +static struct mbox_chan_ops pcc_chan_ops = {
> +	.send_data	=	pcc_send_data,
> +	.last_tx_done	=	pcc_tx_done,
> +};
> +
> +static int parse_pcc_subspace(struct acpi_subtable_header *header,
> +		const unsigned long end)
> +{
> +	struct acpi_pcct_subspace *pcct_ss;
> +
> +	if (pcc_mbox_ctrl.num_chans <= MAX_PCC_SUBSPACES) {
> +		pcct_ss = (struct acpi_pcct_subspace *) header;
> +
> +		if (pcct_ss->header.type != ACPI_PCCT_TYPE_GENERIC_SUBSPACE) {
> +			pr_err("Incorrect PCC Subspace type detected\n");
> +			return -EINVAL;
> +		}
> +
> +		/* New mbox channel entry for each PCC subspace detected. */
> +		pcc_mbox_chan[pcc_mbox_ctrl.num_chans].con_priv = pcct_ss;
> +		pcc_mbox_ctrl.num_chans++;
> +
> +	} else {
> +		pr_err("No more space for PCC subspaces.\n");
> +		return -ENOSPC;
> +	}
> +
> +	return 0;
> +}
> +
> +static int __init acpi_pcc_probe(void)
> +{
> +	acpi_status status = AE_OK;
> +	acpi_size pcct_tbl_header_size;
> +	struct acpi_table_pcct *pcct_tbl;
> +
> +	/* Search for PCCT */
> +	status = acpi_get_table_with_size(ACPI_SIG_PCCT, 0,
> +			(struct acpi_table_header **)&pcct_tbl,
> +			&pcct_tbl_header_size);
> +
> +	if (ACPI_SUCCESS(status) && !pcct_tbl) {
> +		pr_warn("PCCT header not found.\n");
> +		status = AE_NOT_FOUND;
> +		goto out_err;
> +	}
> +
> +	status = acpi_table_parse_entries(ACPI_SIG_PCCT,
> +			sizeof(struct acpi_table_pcct),
> +			ACPI_PCCT_TYPE_GENERIC_SUBSPACE,
> +			parse_pcc_subspace, MAX_PCC_SUBSPACES);
> +
> +	if (ACPI_SUCCESS(status))
> +		pr_err("Error parsing PCC subspaces from PCCT\n");
> +
> +	pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl.num_chans);
> +
> +	pcc_mbox_ctrl.chans = pcc_mbox_chan;
> +	pcc_mbox_ctrl.ops = &pcc_chan_ops;
> +	pcc_mbox_ctrl.txdone_poll = true;
> +	pcc_mbox_ctrl.txpoll_period = 1;
> +
> +out_err:
> +	return ACPI_SUCCESS(status) ? 1 : 0;

Should the return value of 1 here be -EINVAL?

Thanks and best regards
-Lv

> +}
> +
> +static int pcc_mbox_probe(struct platform_device *pdev)
> +{
> +	int ret = 0;
> +
> +	pcc_mbox_ctrl.dev = &pdev->dev;
> +
> +	pr_info("Registering PCC driver as Mailbox controller\n");
> +	ret = mbox_controller_register(&pcc_mbox_ctrl);
> +
> +	if (ret) {
> +		pr_err("Err registering PCC as Mailbox controller: %d\n", ret);
> +		ret = -ENODEV;
> +	}
> +
> +	return ret;
> +}
> +
> +struct platform_driver pcc_mbox_driver = {
> +	.probe = pcc_mbox_probe,
> +	.driver = {
> +		.name = "PCCT",
> +		.owner = THIS_MODULE,
> +	},
> +};
> +
> +static int __init pcc_init(void)
> +{
> +	int ret;
> +	struct platform_device *pcc_pdev;
> +
> +	if (acpi_disabled)
> +		return -ENODEV;
> +
> +	/* Check if PCC support is available. */
> +	ret = acpi_pcc_probe();
> +
> +	if (ret) {
> +		pr_debug("ACPI PCC probe failed.\n");
> +		return -EINVAL;
> +	}
> +
> +	pcc_pdev = platform_create_bundle(&pcc_mbox_driver,
> +			pcc_mbox_probe, NULL, 0, NULL, 0);
> +
> +	if (!pcc_pdev) {
> +		pr_err("Err creating PCC platform bundle\n");
> +		return -ENODEV;
> +	}
> +
> +	return 0;
> +}
> +
> +device_initcall(pcc_init);
> --
> 1.9.1
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Ashwin Chaugule Sept. 5, 2014, 2:23 a.m. UTC | #2 
Hi Lv,

On 4 September 2014 21:56, Zheng, Lv <lv.zheng@intel.com> wrote:
>> +     spin_lock_irqsave(&chan->lock, flags);
>> +     chan->msg_free = 0;
>> +     chan->msg_count = 0;
>> +     chan->active_req = NULL;
>> +     chan->cl = cl;
>> +     init_completion(&chan->tx_complete);
>> +
>> +     if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
>
> The tab should be a space here?
>

Not sure where you're seeing the tab.

>> +static bool pcc_tx_done(struct mbox_chan *chan)
>> +{
>> +     struct acpi_pcct_subspace *pcct_ss = chan->con_priv;
>> +     struct acpi_pcct_shared_memory *generic_comm_base =
>> +             (struct acpi_pcct_shared_memory *) pcct_ss->base_address;
>> +     u16 cmd_delay = pcct_ss->min_turnaround_time;
>
> Should these parameters be acquired with chan-lock held?
> Is that possible to change them during runtime?
>

No. These parameters don't change.

>> +/* Channel lock is already held by mbox controller code. */
>> +static int pcc_send_data(struct mbox_chan *chan, void *data)
>> +{
>> +     struct acpi_pcct_subspace *pcct_ss = chan->con_priv;
>> +     struct acpi_pcct_shared_memory *generic_comm_base =
>> +             (struct acpi_pcct_shared_memory *) pcct_ss->base_address;
>
>
> Ditto.
>

Same as above.

>> +out_err:
>> +     return ACPI_SUCCESS(status) ? 1 : 0;
>
> Should the return value of 1 here be -EINVAL?
>

I dont think it really matters, the caller returns -EINVAL anyway.

Thanks,
Ashwin
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Zheng, Lv Sept. 5, 2014, 6:35 a.m. UTC | #3 
Hi,

> From: linux-acpi-owner@vger.kernel.org [mailto:linux-acpi-owner@vger.kernel.org] On Behalf Of Ashwin Chaugule

> Sent: Friday, September 05, 2014 10:24 AM

> 

> Hi Lv,

> 

> On 4 September 2014 21:56, Zheng, Lv <lv.zheng@intel.com> wrote:

> >> +     spin_lock_irqsave(&chan->lock, flags);

> >> +     chan->msg_free = 0;

> >> +     chan->msg_count = 0;

> >> +     chan->active_req = NULL;

> >> +     chan->cl = cl;

> >> +     init_completion(&chan->tx_complete);

> >> +

> >> +     if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)

> >

> > The tab should be a space here?

> >

> 

> Not sure where you're seeing the tab.


It is a tab here after " txdone_method".

> >> +static bool pcc_tx_done(struct mbox_chan *chan)

> >> +{

> >> +     struct acpi_pcct_subspace *pcct_ss = chan->con_priv;

> >> +     struct acpi_pcct_shared_memory *generic_comm_base =

> >> +             (struct acpi_pcct_shared_memory *) pcct_ss->base_address;

> >> +     u16 cmd_delay = pcct_ss->min_turnaround_time;

> >

> > Should these parameters be acquired with chan-lock held?

> > Is that possible to change them during runtime?

> >

> 

> No. These parameters don't change.


OK.
Then that's up to you. :-)

> 

> >> +/* Channel lock is already held by mbox controller code. */

> >> +static int pcc_send_data(struct mbox_chan *chan, void *data)

> >> +{

> >> +     struct acpi_pcct_subspace *pcct_ss = chan->con_priv;

> >> +     struct acpi_pcct_shared_memory *generic_comm_base =

> >> +             (struct acpi_pcct_shared_memory *) pcct_ss->base_address;

> >

> >

> > Ditto.

> >

> 

> Same as above.

> 

> >> +out_err:

> >> +     return ACPI_SUCCESS(status) ? 1 : 0;

> >

> > Should the return value of 1 here be -EINVAL?

> >

> 

> I dont think it really matters, the caller returns -EINVAL anyway.


This is not a "bool" return value or "reversed bool" return value.
Why not use errno for all "int" return value across all initialization/finalization functions?
And in the caller, you can:
 +	if (ret) {
 +		pr_debug("ACPI PCC probe failed.\n");
 +		return ret;
 +	}
BTW, wasn't it better to return -ENODEV here?

Thanks
-Lv

> 

> Thanks,

> Ashwin

> --

> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in

> the body of a message to majordomo@vger.kernel.org

> More majordomo info at  http://vger.kernel.org/majordomo-info.html
Ashwin Chaugule Sept. 5, 2014, 4:15 p.m. UTC | #4 
Hi Lv,

On 5 September 2014 02:35, Zheng, Lv <lv.zheng@intel.com> wrote:
>>
>> On 4 September 2014 21:56, Zheng, Lv <lv.zheng@intel.com> wrote:
>> >> +     spin_lock_irqsave(&chan->lock, flags);
>> >> +     chan->msg_free = 0;
>> >> +     chan->msg_count = 0;
>> >> +     chan->active_req = NULL;
>> >> +     chan->cl = cl;
>> >> +     init_completion(&chan->tx_complete);
>> >> +
>> >> +     if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
>> >
>> > The tab should be a space here?
>> >
>>
>> Not sure where you're seeing the tab.
>
> It is a tab here after " txdone_method".
>>>
>> >> +out_err:
>> >> +     return ACPI_SUCCESS(status) ? 1 : 0;
>> >
>> > Should the return value of 1 here be -EINVAL?
>> >
>>
>> I dont think it really matters, the caller returns -EINVAL anyway.
>
> This is not a "bool" return value or "reversed bool" return value.
> Why not use errno for all "int" return value across all initialization/finalization functions?

Ok, I'll make it consistent with errnos. Since it doesnt change the
logic of the code, I wont send out a V7 until there is any other
feedback from others.

Thanks,
Ashwin
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Ashwin Chaugule Sept. 8, 2014, 12:48 p.m. UTC | #5 
Hello Mark, Arnd, Lv,

On 5 September 2014 12:15, Ashwin Chaugule <ashwin.chaugule@linaro.org> wrote:
> On 5 September 2014 02:35, Zheng, Lv <lv.zheng@intel.com> wrote:
>>>
>>> On 4 September 2014 21:56, Zheng, Lv <lv.zheng@intel.com> wrote:
>>> >> +     spin_lock_irqsave(&chan->lock, flags);
>>> >> +     chan->msg_free = 0;
>>> >> +     chan->msg_count = 0;
>>> >> +     chan->active_req = NULL;
>>> >> +     chan->cl = cl;
>>> >> +     init_completion(&chan->tx_complete);
>>> >> +
>>> >> +     if (chan->txdone_method == TXDONE_BY_POLL && cl->knows_txdone)
>>> >
>>> > The tab should be a space here?
>>> >
>>>
>>> Not sure where you're seeing the tab.
>>
>> It is a tab here after " txdone_method".
>>>>
>>> >> +out_err:
>>> >> +     return ACPI_SUCCESS(status) ? 1 : 0;
>>> >
>>> > Should the return value of 1 here be -EINVAL?
>>> >
>>>
>>> I dont think it really matters, the caller returns -EINVAL anyway.
>>
>> This is not a "bool" return value or "reversed bool" return value.
>> Why not use errno for all "int" return value across all initialization/finalization functions?
>
> Ok, I'll make it consistent with errnos. Since it doesnt change the
> logic of the code, I wont send out a V7 until there is any other
> feedback from others.
>

Anymore feedback on Patchset V6? I will address Lv's comments above in V7 soon.

Thanks,
Ashwin
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/drivers/mailbox/Kconfig b/drivers/mailbox/Kconfig
index c8b5c13..e08cc83 100644
--- a/drivers/mailbox/Kconfig
+++ b/drivers/mailbox/Kconfig
@@ -50,4 +50,16 @@  config OMAP_MBOX_KFIFO_SIZE
 	  Specify the default size of mailbox's kfifo buffers (bytes).
 	  This can also be changed at runtime (via the mbox_kfifo_size
 	  module parameter).
+
+config PCC
+	bool "Platform Communication Channel Driver"
+	depends on ACPI
+	help
+		ACPI 5.0+ spec defines a generic mode of communication
+		between the OS and a platform such as the BMC. This medium
+		(PCC) is typically used by CPPC (ACPI CPU Performance management),
+		RAS (ACPI reliability protocol) and MPST (ACPI Memory power
+		states). Select this driver if your platform implements the
+		PCC clients mentioned above.
+
 endif
diff --git a/drivers/mailbox/Makefile b/drivers/mailbox/Makefile
index 2fa343a..0b09d6f 100644
--- a/drivers/mailbox/Makefile
+++ b/drivers/mailbox/Makefile
@@ -9,3 +9,5 @@  obj-$(CONFIG_OMAP1_MBOX)	+= mailbox_omap1.o
 mailbox_omap1-objs		:= mailbox-omap1.o
 obj-$(CONFIG_OMAP2PLUS_MBOX)	+= mailbox_omap2.o
 mailbox_omap2-objs		:= mailbox-omap2.o
+
+obj-$(CONFIG_PCC)			+= pcc.o
diff --git a/drivers/mailbox/mailbox.c b/drivers/mailbox/mailbox.c
index 63ecc17..9d9366a 100644
--- a/drivers/mailbox/mailbox.c
+++ b/drivers/mailbox/mailbox.c
@@ -21,9 +21,7 @@ 
 #include <linux/mailbox_client.h>
 #include <linux/mailbox_controller.h>
 
-#define TXDONE_BY_IRQ	BIT(0) /* controller has remote RTR irq */
-#define TXDONE_BY_POLL	BIT(1) /* controller can read status of last TX */
-#define TXDONE_BY_ACK	BIT(2) /* S/W ACK recevied by Client ticks the TX */
+#include "mailbox.h"
 
 static LIST_HEAD(mbox_cons);
 static DEFINE_MUTEX(con_mutex);
diff --git a/drivers/mailbox/mailbox.h b/drivers/mailbox/mailbox.h
new file mode 100644
index 0000000..5a15a25
--- /dev/null
+++ b/drivers/mailbox/mailbox.h
@@ -0,0 +1,16 @@ 
+/*
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#ifndef __MAILBOX_H
+#define __MAILBOX_H
+
+#define TXDONE_BY_IRQ	BIT(0) /* controller has remote RTR irq */
+#define TXDONE_BY_POLL	BIT(1) /* controller can read status of last TX */
+#define TXDONE_BY_ACK	BIT(2) /* S/W ACK recevied by Client ticks the TX */
+
+#endif /* __MAILBOX_H */
+
+
diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
new file mode 100644
index 0000000..7831a01
--- /dev/null
+++ b/drivers/mailbox/pcc.c
@@ -0,0 +1,279 @@ 
+/*
+ *	Copyright (C) 2014 Linaro Ltd.
+ *	Author:	Ashwin Chaugule <ashwin.chaugule@linaro.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ */
+
+#include <linux/acpi.h>
+#include <linux/cpufreq.h>
+#include <linux/delay.h>
+#include <linux/io.h>
+#include <linux/init.h>
+#include <linux/ioctl.h>
+#include <linux/module.h>
+#include <linux/uaccess.h>
+#include <linux/vmalloc.h>
+#include <linux/platform_device.h>
+#include <linux/mailbox_controller.h>
+#include <linux/mailbox_client.h>
+
+#include "mailbox.h"
+
+#define MAX_PCC_SUBSPACES	256
+#define PCCS_SS_SIG_MAGIC	0x50434300
+#define PCC_CMD_COMPLETE	0x1
+
+static struct mbox_chan pcc_mbox_chan[MAX_PCC_SUBSPACES];
+static struct mbox_controller pcc_mbox_ctrl = {};
+
+struct mbox_chan *pcc_mbox_request_channel(struct mbox_client *cl,
+		int index)
+{
+	struct device *dev = pcc_mbox_ctrl.dev;
+	struct mbox_chan *chan;
+	unsigned long flags;
+
+	/*
+	 * Each PCC Subspace is a Mailbox Channel.
+	 * The PCC Clients get their PCC Subspace ID
+	 * from their own tables and pass it here.
+	 * This returns a pointer to the PCC subspace
+	 * for the Client to operate on.
+	 */
+	chan = &pcc_mbox_chan[index];
+
+	if (!chan || chan->cl) {
+		dev_err(dev, "%s: PCC mailbox not free\n", __func__);
+		return ERR_PTR(-EBUSY);
+	}
+
+	spin_lock_irqsave(&chan->lock, flags);
+	chan->msg_free = 0;
+	chan->msg_count = 0;
+	chan->active_req = NULL;
+	chan->cl = cl;
+	init_completion(&chan->tx_complete);
+
+	if (chan->txdone_method	== TXDONE_BY_POLL && cl->knows_txdone)
+		chan->txdone_method |= TXDONE_BY_ACK;
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+
+	return chan;
+}
+EXPORT_SYMBOL_GPL(pcc_mbox_request_channel);
+
+void pcc_mbox_free_channel(struct mbox_chan *chan)
+{
+	unsigned long flags;
+
+	if (!chan || !chan->cl)
+		return;
+
+	spin_lock_irqsave(&chan->lock, flags);
+	chan->cl = NULL;
+	chan->active_req = NULL;
+	if (chan->txdone_method == (TXDONE_BY_POLL | TXDONE_BY_ACK))
+		chan->txdone_method = TXDONE_BY_POLL;
+
+	spin_unlock_irqrestore(&chan->lock, flags);
+}
+EXPORT_SYMBOL_GPL(pcc_mbox_free_channel);
+
+static bool pcc_tx_done(struct mbox_chan *chan)
+{
+	struct acpi_pcct_subspace *pcct_ss = chan->con_priv;
+	struct acpi_pcct_shared_memory *generic_comm_base =
+		(struct acpi_pcct_shared_memory *) pcct_ss->base_address;
+	u16 cmd_delay = pcct_ss->min_turnaround_time;
+
+	/* Wait for Platform to consume. */
+	while (!(readw_relaxed(&generic_comm_base->status) & PCC_CMD_COMPLETE))
+		udelay(cmd_delay);
+
+	return true;
+}
+
+static int get_subspace_id(struct mbox_chan *chan)
+{
+	int id = chan - pcc_mbox_chan;
+
+	if (id < 0 || id > pcc_mbox_ctrl.num_chans)
+		return -ENOENT;
+
+	return id;
+}
+
+/* Channel lock is already held by mbox controller code. */
+static int pcc_send_data(struct mbox_chan *chan, void *data)
+{
+	struct acpi_pcct_subspace *pcct_ss = chan->con_priv;
+	struct acpi_pcct_shared_memory *generic_comm_base =
+		(struct acpi_pcct_shared_memory *) pcct_ss->base_address;
+	struct acpi_generic_address doorbell;
+	u64 doorbell_preserve;
+	u64 doorbell_val;
+	u64 doorbell_write;
+	u16 cmd = *(u16 *) data;
+	u16 ss_idx = -1;
+	int ret = 0;
+
+	ss_idx = get_subspace_id(chan);
+
+	if (ss_idx < 0) {
+		pr_err("Invalid Subspace ID from PCC client\n");
+		ret = -EINVAL;
+		goto out_err;
+	}
+
+	doorbell = pcct_ss->doorbell_register;
+	doorbell_preserve = pcct_ss->preserve_mask;
+	doorbell_write = pcct_ss->write_mask;
+
+	/* Write to the shared comm region. */
+	writew(cmd, &generic_comm_base->command);
+
+	/* Write Subspace MAGIC value so platform can identify destination. */
+	writel((PCCS_SS_SIG_MAGIC | ss_idx), &generic_comm_base->signature);
+
+	/* Flip CMD COMPLETE bit */
+	writew(0, &generic_comm_base->status);
+
+	/* Sync notification from OSPM to Platform. */
+	acpi_read(&doorbell_val, &doorbell);
+	acpi_write((doorbell_val & doorbell_preserve) | doorbell_write,
+			&doorbell);
+
+out_err:
+	return ret;
+}
+
+static struct mbox_chan_ops pcc_chan_ops = {
+	.send_data	=	pcc_send_data,
+	.last_tx_done	=	pcc_tx_done,
+};
+
+static int parse_pcc_subspace(struct acpi_subtable_header *header,
+		const unsigned long end)
+{
+	struct acpi_pcct_subspace *pcct_ss;
+
+	if (pcc_mbox_ctrl.num_chans <= MAX_PCC_SUBSPACES) {
+		pcct_ss = (struct acpi_pcct_subspace *) header;
+
+		if (pcct_ss->header.type != ACPI_PCCT_TYPE_GENERIC_SUBSPACE) {
+			pr_err("Incorrect PCC Subspace type detected\n");
+			return -EINVAL;
+		}
+
+		/* New mbox channel entry for each PCC subspace detected. */
+		pcc_mbox_chan[pcc_mbox_ctrl.num_chans].con_priv = pcct_ss;
+		pcc_mbox_ctrl.num_chans++;
+
+	} else {
+		pr_err("No more space for PCC subspaces.\n");
+		return -ENOSPC;
+	}
+
+	return 0;
+}
+
+static int __init acpi_pcc_probe(void)
+{
+	acpi_status status = AE_OK;
+	acpi_size pcct_tbl_header_size;
+	struct acpi_table_pcct *pcct_tbl;
+
+	/* Search for PCCT */
+	status = acpi_get_table_with_size(ACPI_SIG_PCCT, 0,
+			(struct acpi_table_header **)&pcct_tbl,
+			&pcct_tbl_header_size);
+
+	if (ACPI_SUCCESS(status) && !pcct_tbl) {
+		pr_warn("PCCT header not found.\n");
+		status = AE_NOT_FOUND;
+		goto out_err;
+	}
+
+	status = acpi_table_parse_entries(ACPI_SIG_PCCT,
+			sizeof(struct acpi_table_pcct),
+			ACPI_PCCT_TYPE_GENERIC_SUBSPACE,
+			parse_pcc_subspace, MAX_PCC_SUBSPACES);
+
+	if (ACPI_SUCCESS(status))
+		pr_err("Error parsing PCC subspaces from PCCT\n");
+
+	pr_info("Detected %d PCC Subspaces\n", pcc_mbox_ctrl.num_chans);
+
+	pcc_mbox_ctrl.chans = pcc_mbox_chan;
+	pcc_mbox_ctrl.ops = &pcc_chan_ops;
+	pcc_mbox_ctrl.txdone_poll = true;
+	pcc_mbox_ctrl.txpoll_period = 1;
+
+out_err:
+	return ACPI_SUCCESS(status) ? 1 : 0;
+}
+
+static int pcc_mbox_probe(struct platform_device *pdev)
+{
+	int ret = 0;
+
+	pcc_mbox_ctrl.dev = &pdev->dev;
+
+	pr_info("Registering PCC driver as Mailbox controller\n");
+	ret = mbox_controller_register(&pcc_mbox_ctrl);
+
+	if (ret) {
+		pr_err("Err registering PCC as Mailbox controller: %d\n", ret);
+		ret = -ENODEV;
+	}
+
+	return ret;
+}
+
+struct platform_driver pcc_mbox_driver = {
+	.probe = pcc_mbox_probe,
+	.driver = {
+		.name = "PCCT",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init pcc_init(void)
+{
+	int ret;
+	struct platform_device *pcc_pdev;
+
+	if (acpi_disabled)
+		return -ENODEV;
+
+	/* Check if PCC support is available. */
+	ret = acpi_pcc_probe();
+
+	if (ret) {
+		pr_debug("ACPI PCC probe failed.\n");
+		return -EINVAL;
+	}
+
+	pcc_pdev = platform_create_bundle(&pcc_mbox_driver,
+			pcc_mbox_probe, NULL, 0, NULL, 0);
+
+	if (!pcc_pdev) {
+		pr_err("Err creating PCC platform bundle\n");
+		return -ENODEV;
+	}
+
+	return 0;
+}
+
+device_initcall(pcc_init);