diff mbox series

[09/11] mmc: sdhci-cadence: Add Pensando Elba SoC support

Message ID 20220406233648.21644-10-brad@pensando.io
State New
Headers show
Series Support Pensando Elba SoC | expand

Commit Message

Brad Larson April 6, 2022, 11:36 p.m. UTC 
Add support for Pensando Elba SoC which explicitly controls
byte-lane enables on writes.  Add priv_write_l() which is
used on Elba platforms for byte-lane control.

Select MMC_SDHCI_IO_ACCESSORS for MMC_SDHCI_CADENCE which
allows Elba SoC sdhci_elba_ops to overwrite the SDHCI
IO memory accessors.

Signed-off-by: Brad Larson <brad@pensando.io>
---
Change from V3:
- Change from elba-emmc to elba-sd4hc to match file convention

 drivers/mmc/host/Kconfig         |   1 +
 drivers/mmc/host/sdhci-cadence.c | 148 ++++++++++++++++++++++++++++---
 2 files changed, 135 insertions(+), 14 deletions(-)

Comments

Arnd Bergmann April 7, 2022, 6:45 a.m. UTC | #1 
On Thu, Apr 7, 2022 at 1:36 AM Brad Larson <brad@pensando.io> wrote:
> @@ -350,7 +461,7 @@ static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
>  static int sdhci_cdns_probe(struct platform_device *pdev)
>  {
>         struct sdhci_host *host;
> -       const struct sdhci_pltfm_data *data;
> +       const struct sdhci_cdns_drv_data *data;
>         struct sdhci_pltfm_host *pltfm_host;
>         struct sdhci_cdns_priv *priv;
>         struct clk *clk;
> @@ -369,10 +480,10 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
>
>         data = of_device_get_match_data(dev);
>         if (!data)
> -               data = &sdhci_cdns_pltfm_data;
> +               data = &sdhci_cdns_drv_data;
>
>         nr_phy_params = sdhci_cdns_phy_param_count(dev->of_node);
> -       host = sdhci_pltfm_init(pdev, data,
> +       host = sdhci_pltfm_init(pdev, &data->pltfm_data,
>                                 struct_size(priv, phy_params, nr_phy_params));
>         if (IS_ERR(host)) {
>                 ret = PTR_ERR(host);
> @@ -389,6 +500,11 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
>         host->ioaddr += SDHCI_CDNS_SRS_BASE;
>         host->mmc_host_ops.hs400_enhanced_strobe =
>                                 sdhci_cdns_hs400_enhanced_strobe;
> +       if (data->init) {
> +               ret = data->init(pdev);
> +               if (ret)
> +                       goto free;
> +       }
>         sdhci_enable_v4_mode(host);
>         __sdhci_read_caps(host, &version, NULL, NULL);

I'm not sure about the abstraction here. The approach of having a single
driver with some platform specific quirks like you do here works fine if the
differences between hardware implementations are fairly minor, but if there
are a larger number of variants, or the differences become too big, the
better approach is to have separate top-level driver instances that call
into a more generic driver, continuing the call chain

elba_drv_init()
 -> sdhci_cdns_probe()
     -> sdhci_pltfm_init()
         -> sdhci_add_host()
             -> mmc_add_host()

with each one being a more specific version of the one below it.
At the moment, it doesn't quite require having a custom driver,
but I fear that it it would get hard to rework if it continues to grow
other front-ends. It may be better to do the abstraction right away,
even if the elba driver becomes rather trivial.

Ulf, any preferences?

         Arnd
Adrian Hunter April 7, 2022, 7:13 a.m. UTC | #2 
On 07/04/2022 9.45, Arnd Bergmann wrote:
> On Thu, Apr 7, 2022 at 1:36 AM Brad Larson <brad@pensando.io> wrote:
>> @@ -350,7 +461,7 @@ static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
>>  static int sdhci_cdns_probe(struct platform_device *pdev)
>>  {
>>         struct sdhci_host *host;
>> -       const struct sdhci_pltfm_data *data;
>> +       const struct sdhci_cdns_drv_data *data;
>>         struct sdhci_pltfm_host *pltfm_host;
>>         struct sdhci_cdns_priv *priv;
>>         struct clk *clk;
>> @@ -369,10 +480,10 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
>>
>>         data = of_device_get_match_data(dev);
>>         if (!data)
>> -               data = &sdhci_cdns_pltfm_data;
>> +               data = &sdhci_cdns_drv_data;
>>
>>         nr_phy_params = sdhci_cdns_phy_param_count(dev->of_node);
>> -       host = sdhci_pltfm_init(pdev, data,
>> +       host = sdhci_pltfm_init(pdev, &data->pltfm_data,
>>                                 struct_size(priv, phy_params, nr_phy_params));
>>         if (IS_ERR(host)) {
>>                 ret = PTR_ERR(host);
>> @@ -389,6 +500,11 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
>>         host->ioaddr += SDHCI_CDNS_SRS_BASE;
>>         host->mmc_host_ops.hs400_enhanced_strobe =
>>                                 sdhci_cdns_hs400_enhanced_strobe;
>> +       if (data->init) {
>> +               ret = data->init(pdev);
>> +               if (ret)
>> +                       goto free;
>> +       }
>>         sdhci_enable_v4_mode(host);
>>         __sdhci_read_caps(host, &version, NULL, NULL);
> 
> I'm not sure about the abstraction here. The approach of having a single
> driver with some platform specific quirks like you do here works fine if the
> differences between hardware implementations are fairly minor, but if there
> are a larger number of variants, or the differences become too big, the
> better approach is to have separate top-level driver instances that call
> into a more generic driver, continuing the call chain
> 
> elba_drv_init()
>  -> sdhci_cdns_probe()
>      -> sdhci_pltfm_init()
>          -> sdhci_add_host()
>              -> mmc_add_host()
> 
> with each one being a more specific version of the one below it.
> At the moment, it doesn't quite require having a custom driver,
> but I fear that it it would get hard to rework if it continues to grow
> other front-ends. It may be better to do the abstraction right away,
> even if the elba driver becomes rather trivial.
> 
> Ulf, any preferences?
> 

What is the relationship between cadence and pensando elba?
Brad Larson April 7, 2022, 5:06 p.m. UTC | #3 
On Thu, Apr 7, 2022 at 12:13 AM Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> What is the relationship between cadence and pensando elba?

Pensando licensed the cadence controller, its 100% cadence IP.  The
integration issue we ran into was with the accessors where we have the
workaround.  The initial patch added a separate Elba driver file but
the feedback was the Elba support didn't justify doing that and to add
to sdhci-cacence.c.

Regards,
Brad
Arnd Bergmann April 7, 2022, 8:38 p.m. UTC | #4 
On Thu, Apr 7, 2022 at 7:06 PM Brad Larson <brad@pensando.io> wrote:
> On Thu, Apr 7, 2022 at 12:13 AM Adrian Hunter <adrian.hunter@intel.com> wrote:
> >
> > What is the relationship between cadence and pensando elba?
>
> Pensando licensed the cadence controller, its 100% cadence IP.  The
> integration issue we ran into was with the accessors where we have the
> workaround.  The initial patch added a separate Elba driver file but
> the feedback was the Elba support didn't justify doing that and to add
> to sdhci-cacence.c.

I looked back at the earlier reviews now, I think the main problem with
versions 1 and 2 was that it had the abstraction the wrong way around,
so you added the complexity of having multiple files, without the benefits.

I still think that the cleanest approach would be to have it the way I
suggested in my reply to v1, with an elba specific platform driver
that calls into the generic cadence code, but the generic code knowing
nothing about the front-end.

Then again, it sounds like there was already an agreement about
the approach you took here, so let's stay with that and hope we don't
get any other chips with the same IP block in the future.

         Arnd
diff mbox series

Patch

diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
index af6c3c329076..f3f4dc95f21e 100644
--- a/drivers/mmc/host/Kconfig
+++ b/drivers/mmc/host/Kconfig
@@ -243,6 +243,7 @@  config MMC_SDHCI_CADENCE
 	tristate "SDHCI support for the Cadence SD/SDIO/eMMC controller"
 	depends on MMC_SDHCI_PLTFM
 	depends on OF
+	select MMC_SDHCI_IO_ACCESSORS
 	help
 	  This selects the Cadence SD/SDIO/eMMC driver.
 
diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
index 6f2de54a5987..e9b7f80e8cf0 100644
--- a/drivers/mmc/host/sdhci-cadence.c
+++ b/drivers/mmc/host/sdhci-cadence.c
@@ -66,7 +66,11 @@  struct sdhci_cdns_phy_param {
 
 struct sdhci_cdns_priv {
 	void __iomem *hrs_addr;
+	void __iomem *ctl_addr;	/* write control */
+	spinlock_t wrlock;	/* write lock */
 	bool enhanced_strobe;
+	void (*priv_write_l)(struct sdhci_cdns_priv *priv, u32 val,
+			     void __iomem *reg);
 	unsigned int nr_phy_params;
 	struct sdhci_cdns_phy_param phy_params[];
 };
@@ -76,6 +80,11 @@  struct sdhci_cdns_phy_cfg {
 	u8 addr;
 };
 
+struct sdhci_cdns_drv_data {
+	int (*init)(struct platform_device *pdev);
+	const struct sdhci_pltfm_data pltfm_data;
+};
+
 static const struct sdhci_cdns_phy_cfg sdhci_cdns_phy_cfgs[] = {
 	{ "cdns,phy-input-delay-sd-highspeed", SDHCI_CDNS_PHY_DLY_SD_HS, },
 	{ "cdns,phy-input-delay-legacy", SDHCI_CDNS_PHY_DLY_SD_DEFAULT, },
@@ -90,6 +99,15 @@  static const struct sdhci_cdns_phy_cfg sdhci_cdns_phy_cfgs[] = {
 	{ "cdns,phy-dll-delay-strobe", SDHCI_CDNS_PHY_DLY_STROBE, },
 };
 
+static inline void sdhci_cdns_priv_writel(struct sdhci_cdns_priv *priv,
+					  u32 val, void __iomem *reg)
+{
+	if (unlikely(priv->priv_write_l))
+		priv->priv_write_l(priv, val, reg);
+	else
+		writel(val, reg);
+}
+
 static int sdhci_cdns_write_phy_reg(struct sdhci_cdns_priv *priv,
 				    u8 addr, u8 data)
 {
@@ -104,17 +122,17 @@  static int sdhci_cdns_write_phy_reg(struct sdhci_cdns_priv *priv,
 
 	tmp = FIELD_PREP(SDHCI_CDNS_HRS04_WDATA, data) |
 	      FIELD_PREP(SDHCI_CDNS_HRS04_ADDR, addr);
-	writel(tmp, reg);
+	sdhci_cdns_priv_writel(priv, tmp, reg);
 
 	tmp |= SDHCI_CDNS_HRS04_WR;
-	writel(tmp, reg);
+	sdhci_cdns_priv_writel(priv, tmp, reg);
 
 	ret = readl_poll_timeout(reg, tmp, tmp & SDHCI_CDNS_HRS04_ACK, 0, 10);
 	if (ret)
 		return ret;
 
 	tmp &= ~SDHCI_CDNS_HRS04_WR;
-	writel(tmp, reg);
+	sdhci_cdns_priv_writel(priv, tmp, reg);
 
 	ret = readl_poll_timeout(reg, tmp, !(tmp & SDHCI_CDNS_HRS04_ACK),
 				 0, 10);
@@ -191,7 +209,7 @@  static void sdhci_cdns_set_emmc_mode(struct sdhci_cdns_priv *priv, u32 mode)
 	tmp = readl(priv->hrs_addr + SDHCI_CDNS_HRS06);
 	tmp &= ~SDHCI_CDNS_HRS06_MODE;
 	tmp |= FIELD_PREP(SDHCI_CDNS_HRS06_MODE, mode);
-	writel(tmp, priv->hrs_addr + SDHCI_CDNS_HRS06);
+	sdhci_cdns_priv_writel(priv, tmp, priv->hrs_addr + SDHCI_CDNS_HRS06);
 }
 
 static u32 sdhci_cdns_get_emmc_mode(struct sdhci_cdns_priv *priv)
@@ -223,7 +241,7 @@  static int sdhci_cdns_set_tune_val(struct sdhci_host *host, unsigned int val)
 	 */
 	for (i = 0; i < 2; i++) {
 		tmp |= SDHCI_CDNS_HRS06_TUNE_UP;
-		writel(tmp, reg);
+		sdhci_cdns_priv_writel(priv, tmp, reg);
 
 		ret = readl_poll_timeout(reg, tmp,
 					 !(tmp & SDHCI_CDNS_HRS06_TUNE_UP),
@@ -309,6 +327,88 @@  static void sdhci_cdns_set_uhs_signaling(struct sdhci_host *host,
 		sdhci_set_uhs_signaling(host, timing);
 }
 
+/*
+ * The Pensando Elba SoC explicitly controls byte-lane enables on writes
+ * which includes writes to the HRS registers.
+ */
+static void elba_priv_write_l(struct sdhci_cdns_priv *priv, u32 val,
+			      void __iomem *reg)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&priv->wrlock, flags);
+	writel(0x78, priv->ctl_addr);
+	writel(val, reg);
+	spin_unlock_irqrestore(&priv->wrlock, flags);
+}
+
+static void elba_write_l(struct sdhci_host *host, u32 val, int reg)
+{
+	elba_priv_write_l(sdhci_cdns_priv(host), val, host->ioaddr + reg);
+}
+
+static void elba_write_w(struct sdhci_host *host, u16 val, int reg)
+{
+	struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
+	unsigned long flags;
+	u32 m = (reg & 0x3);
+	u32 msk = (0x3 << (m));
+
+	spin_lock_irqsave(&priv->wrlock, flags);
+	writel(msk << 3, priv->ctl_addr);
+	writew(val, host->ioaddr + reg);
+	spin_unlock_irqrestore(&priv->wrlock, flags);
+}
+
+static void elba_write_b(struct sdhci_host *host, u8 val, int reg)
+{
+	struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
+	unsigned long flags;
+	u32 m = (reg & 0x3);
+	u32 msk = (0x1 << (m));
+
+	spin_lock_irqsave(&priv->wrlock, flags);
+	writel(msk << 3, priv->ctl_addr);
+	writeb(val, host->ioaddr + reg);
+	spin_unlock_irqrestore(&priv->wrlock, flags);
+}
+
+static const struct sdhci_ops sdhci_elba_ops = {
+	.write_l = elba_write_l,
+	.write_w = elba_write_w,
+	.write_b = elba_write_b,
+	.set_clock = sdhci_set_clock,
+	.get_timeout_clock = sdhci_cdns_get_timeout_clock,
+	.set_bus_width = sdhci_set_bus_width,
+	.reset = sdhci_reset,
+	.set_uhs_signaling = sdhci_cdns_set_uhs_signaling,
+};
+
+static int elba_drv_init(struct platform_device *pdev)
+{
+	struct sdhci_host *host = platform_get_drvdata(pdev);
+	struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
+	struct resource *iomem;
+	void __iomem *ioaddr;
+
+	host->mmc->caps |= (MMC_CAP_1_8V_DDR | MMC_CAP_8_BIT_DATA);
+
+	iomem = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!iomem)
+		return -ENOMEM;
+
+	ioaddr = devm_platform_ioremap_resource(pdev, 1);
+	if (IS_ERR(ioaddr))
+		return PTR_ERR(ioaddr);
+
+	priv->ctl_addr = ioaddr;
+	priv->priv_write_l = elba_priv_write_l;
+	spin_lock_init(&priv->wrlock);
+	writel(0x78, priv->ctl_addr);
+
+	return 0;
+}
+
 static const struct sdhci_ops sdhci_cdns_ops = {
 	.set_clock = sdhci_set_clock,
 	.get_timeout_clock = sdhci_cdns_get_timeout_clock,
@@ -318,13 +418,24 @@  static const struct sdhci_ops sdhci_cdns_ops = {
 	.set_uhs_signaling = sdhci_cdns_set_uhs_signaling,
 };
 
-static const struct sdhci_pltfm_data sdhci_cdns_uniphier_pltfm_data = {
-	.ops = &sdhci_cdns_ops,
-	.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
+static const struct sdhci_cdns_drv_data sdhci_cdns_uniphier_drv_data = {
+	.pltfm_data = {
+		.ops = &sdhci_cdns_ops,
+		.quirks2 = SDHCI_QUIRK2_PRESET_VALUE_BROKEN,
+	},
+};
+
+static const struct sdhci_cdns_drv_data sdhci_elba_drv_data = {
+	.init = elba_drv_init,
+	.pltfm_data = {
+		.ops = &sdhci_elba_ops,
+	},
 };
 
-static const struct sdhci_pltfm_data sdhci_cdns_pltfm_data = {
-	.ops = &sdhci_cdns_ops,
+static const struct sdhci_cdns_drv_data sdhci_cdns_drv_data = {
+	.pltfm_data = {
+		.ops = &sdhci_cdns_ops,
+	},
 };
 
 static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
@@ -350,7 +461,7 @@  static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
 static int sdhci_cdns_probe(struct platform_device *pdev)
 {
 	struct sdhci_host *host;
-	const struct sdhci_pltfm_data *data;
+	const struct sdhci_cdns_drv_data *data;
 	struct sdhci_pltfm_host *pltfm_host;
 	struct sdhci_cdns_priv *priv;
 	struct clk *clk;
@@ -369,10 +480,10 @@  static int sdhci_cdns_probe(struct platform_device *pdev)
 
 	data = of_device_get_match_data(dev);
 	if (!data)
-		data = &sdhci_cdns_pltfm_data;
+		data = &sdhci_cdns_drv_data;
 
 	nr_phy_params = sdhci_cdns_phy_param_count(dev->of_node);
-	host = sdhci_pltfm_init(pdev, data,
+	host = sdhci_pltfm_init(pdev, &data->pltfm_data,
 				struct_size(priv, phy_params, nr_phy_params));
 	if (IS_ERR(host)) {
 		ret = PTR_ERR(host);
@@ -389,6 +500,11 @@  static int sdhci_cdns_probe(struct platform_device *pdev)
 	host->ioaddr += SDHCI_CDNS_SRS_BASE;
 	host->mmc_host_ops.hs400_enhanced_strobe =
 				sdhci_cdns_hs400_enhanced_strobe;
+	if (data->init) {
+		ret = data->init(pdev);
+		if (ret)
+			goto free;
+	}
 	sdhci_enable_v4_mode(host);
 	__sdhci_read_caps(host, &version, NULL, NULL);
 
@@ -453,7 +569,11 @@  static const struct dev_pm_ops sdhci_cdns_pm_ops = {
 static const struct of_device_id sdhci_cdns_match[] = {
 	{
 		.compatible = "socionext,uniphier-sd4hc",
-		.data = &sdhci_cdns_uniphier_pltfm_data,
+		.data = &sdhci_cdns_uniphier_drv_data,
+	},
+	{
+		.compatible = "pensando,elba-sd4hc",
+		.data = &sdhci_elba_drv_data
 	},
 	{ .compatible = "cdns,sd4hc" },
 	{ /* sentinel */ }