From: Brad Larson <blarson@amd.com>
Add support for mmc hardware reset with a reset-controller
which would need to be enabled in the device tree with
a supporting driver. The default is disabled for all
existing designs.
Signed-off-by: Brad Larson <blarson@amd.com>
---
drivers/mmc/host/sdhci-cadence.c | 29 +++++++++++++++++++++++++++++
1 file changed, 29 insertions(+)
diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
index c662c63d49fa..35d37b9aba63 100644
--- a/drivers/mmc/host/sdhci-cadence.c
+++ b/drivers/mmc/host/sdhci-cadence.c
@@ -12,6 +12,7 @@
#include <linux/mmc/mmc.h>
#include <linux/of.h>
#include <linux/of_device.h>
+#include <linux/reset.h>
#include "sdhci-pltfm.h"
@@ -70,6 +71,7 @@ struct sdhci_cdns_priv {
spinlock_t wrlock; /* write lock */
bool enhanced_strobe;
void (*priv_writel)(struct sdhci_cdns_priv *priv, u32 val, void __iomem *reg);
+ struct reset_control *rst_hw;
unsigned int nr_phy_params;
struct sdhci_cdns_phy_param phy_params[];
};
@@ -458,6 +460,22 @@ static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
SDHCI_CDNS_HRS06_MODE_MMC_HS400);
}
+static void sdhci_mmc_hw_reset(struct mmc_host *mmc)
+{
+ struct sdhci_host *host = mmc_priv(mmc);
+ struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
+
+ dev_info(mmc_dev(host->mmc), "emmc hardware reset\n");
+
+ reset_control_assert(priv->rst_hw);
+ /* For eMMC, minimum is 1us but give it 9us for good measure */
+ udelay(9);
+
+ reset_control_deassert(priv->rst_hw);
+ /* For eMMC, minimum is 200us but give it 300us for good measure */
+ usleep_range(300, 1000);
+}
+
static int sdhci_cdns_probe(struct platform_device *pdev)
{
struct sdhci_host *host;
@@ -520,6 +538,17 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
if (ret)
goto free;
+ if (host->mmc->caps & MMC_CAP_HW_RESET) {
+ priv->rst_hw = devm_reset_control_get_optional_exclusive(dev, "hw");
+ if (IS_ERR(priv->rst_hw)) {
+ ret = PTR_ERR(priv->rst_hw);
+ if (ret == -ENOENT)
+ priv->rst_hw = NULL;
+ } else {
+ host->mmc_host_ops.card_hw_reset = sdhci_mmc_hw_reset;
+ }
+ }
+
ret = sdhci_add_host(host);
if (ret)
goto free;
--
2.17.1On Sat, 20 Aug 2022 at 21:58, Brad Larson <brad@pensando.io> wrote:
>
> From: Brad Larson <blarson@amd.com>
>
> Add support for mmc hardware reset with a reset-controller
> which would need to be enabled in the device tree with
> a supporting driver. The default is disabled for all
> existing designs.
>
> Signed-off-by: Brad Larson <blarson@amd.com>
> ---
> drivers/mmc/host/sdhci-cadence.c | 29 +++++++++++++++++++++++++++++
> 1 file changed, 29 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
> index c662c63d49fa..35d37b9aba63 100644
> --- a/drivers/mmc/host/sdhci-cadence.c
> +++ b/drivers/mmc/host/sdhci-cadence.c
> @@ -12,6 +12,7 @@
> #include <linux/mmc/mmc.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> +#include <linux/reset.h>
>
> #include "sdhci-pltfm.h"
>
> @@ -70,6 +71,7 @@ struct sdhci_cdns_priv {
> spinlock_t wrlock; /* write lock */
> bool enhanced_strobe;
> void (*priv_writel)(struct sdhci_cdns_priv *priv, u32 val, void __iomem *reg);
> + struct reset_control *rst_hw;
> unsigned int nr_phy_params;
> struct sdhci_cdns_phy_param phy_params[];
> };
> @@ -458,6 +460,22 @@ static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
> SDHCI_CDNS_HRS06_MODE_MMC_HS400);
> }
>
> +static void sdhci_mmc_hw_reset(struct mmc_host *mmc)
Nitpick: Probably better to be consistent with the prefixes for
function names. So, I suggest changing this to
"sdhci_cdns_mmc_hw_reset".
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
> +
> + dev_info(mmc_dev(host->mmc), "emmc hardware reset\n");
Maybe it's sufficient with dev_dbg?
> +
> + reset_control_assert(priv->rst_hw);
> + /* For eMMC, minimum is 1us but give it 9us for good measure */
> + udelay(9);
> +
> + reset_control_deassert(priv->rst_hw);
> + /* For eMMC, minimum is 200us but give it 300us for good measure */
> + usleep_range(300, 1000);
> +}
> +
> static int sdhci_cdns_probe(struct platform_device *pdev)
> {
> struct sdhci_host *host;
> @@ -520,6 +538,17 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
> if (ret)
> goto free;
>
> + if (host->mmc->caps & MMC_CAP_HW_RESET) {
> + priv->rst_hw = devm_reset_control_get_optional_exclusive(dev, "hw");
> + if (IS_ERR(priv->rst_hw)) {
> + ret = PTR_ERR(priv->rst_hw);
> + if (ret == -ENOENT)
> + priv->rst_hw = NULL;
> + } else {
> + host->mmc_host_ops.card_hw_reset = sdhci_mmc_hw_reset;
> + }
> + }
> +
> ret = sdhci_add_host(host);
> if (ret)
> goto free;
> --
Other than the comments above, I wonder about what merging strategy we
should use for the series. I believe it looks fine for me to pick up
the mmc related patches, thus we can apply patches on a per subsystem
basis, right?
Kind regards
Uffe
On 8/22/22 3:53 AM, Ulf Hansson wrote:
> On Sat, 20 Aug 2022 at 21:58, Brad Larson <brad@pensando.io> wrote:
>> From: Brad Larson <blarson@amd.com>
>>
>> Add support for mmc hardware reset with a reset-controller
>> which would need to be enabled in the device tree with
>> a supporting driver. The default is disabled for all
>> existing designs.
>>
>> Signed-off-by: Brad Larson <blarson@amd.com>
>> ---
>> drivers/mmc/host/sdhci-cadence.c | 29 +++++++++++++++++++++++++++++
>> 1 file changed, 29 insertions(+)
>>
>> diff --git a/drivers/mmc/host/sdhci-cadence.c b/drivers/mmc/host/sdhci-cadence.c
>> index c662c63d49fa..35d37b9aba63 100644
>> --- a/drivers/mmc/host/sdhci-cadence.c
>> +++ b/drivers/mmc/host/sdhci-cadence.c
>> @@ -12,6 +12,7 @@
>> #include <linux/mmc/mmc.h>
>> #include <linux/of.h>
>> #include <linux/of_device.h>
>> +#include <linux/reset.h>
>>
>> #include "sdhci-pltfm.h"
>>
>> @@ -70,6 +71,7 @@ struct sdhci_cdns_priv {
>> spinlock_t wrlock; /* write lock */
>> bool enhanced_strobe;
>> void (*priv_writel)(struct sdhci_cdns_priv *priv, u32 val, void __iomem *reg);
>> + struct reset_control *rst_hw;
>> unsigned int nr_phy_params;
>> struct sdhci_cdns_phy_param phy_params[];
>> };
>> @@ -458,6 +460,22 @@ static void sdhci_cdns_hs400_enhanced_strobe(struct mmc_host *mmc,
>> SDHCI_CDNS_HRS06_MODE_MMC_HS400);
>> }
>>
>> +static void sdhci_mmc_hw_reset(struct mmc_host *mmc)
> Nitpick: Probably better to be consistent with the prefixes for
> function names. So, I suggest changing this to
> "sdhci_cdns_mmc_hw_reset".
Changing to sdhci_cdns_mmc_hw_reset().
>> +{
>> + struct sdhci_host *host = mmc_priv(mmc);
>> + struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
>> +
>> + dev_info(mmc_dev(host->mmc), "emmc hardware reset\n");
> Maybe it's sufficient with dev_dbg?
Changing to dev_dbg().
>> +
>> + reset_control_assert(priv->rst_hw);
>> + /* For eMMC, minimum is 1us but give it 9us for good measure */
>> + udelay(9);
>> +
>> + reset_control_deassert(priv->rst_hw);
>> + /* For eMMC, minimum is 200us but give it 300us for good measure */
>> + usleep_range(300, 1000);
>> +}
>> +
>> static int sdhci_cdns_probe(struct platform_device *pdev)
>> {
>> struct sdhci_host *host;
>> @@ -520,6 +538,17 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
>> if (ret)
>> goto free;
>>
>> + if (host->mmc->caps & MMC_CAP_HW_RESET) {
>> + priv->rst_hw = devm_reset_control_get_optional_exclusive(dev, "hw");
>> + if (IS_ERR(priv->rst_hw)) {
>> + ret = PTR_ERR(priv->rst_hw);
>> + if (ret == -ENOENT)
>> + priv->rst_hw = NULL;
>> + } else {
>> + host->mmc_host_ops.card_hw_reset = sdhci_mmc_hw_reset;
>> + }
>> + }
>> +
>> ret = sdhci_add_host(host);
>> if (ret)
>> goto free;
>> --
> Other than the comments above, I wonder about what merging strategy we
> should use for the series. I believe it looks fine for me to pick up
> the mmc related patches, thus we can apply patches on a per subsystem
> basis, right?
Yes I think so and I'll be looking for guidance on this.
Regards,
Brad
On Mon, Aug 22, 2022 at 12:53:22PM +0200, Ulf Hansson wrote: > Other than the comments above, I wonder about what merging strategy we > should use for the series. I believe it looks fine for me to pick up > the mmc related patches, thus we can apply patches on a per subsystem > basis, right? Yes, if there's no relationship between the different subsystem components (which looks like the case?) they should probably just go separately - they can probably be submitted separately too.
Hi Brad,
On Sa, 2022-08-20 at 12:57 -0700, Brad Larson wrote:
[...]
> +static void sdhci_mmc_hw_reset(struct mmc_host *mmc)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
> +
> + dev_info(mmc_dev(host->mmc), "emmc hardware reset\n");
> +
> + reset_control_assert(priv->rst_hw);
> + /* For eMMC, minimum is 1us but give it 9us for good measure */
> + udelay(9);
At a glance, this seems excessive. Is there a reason 9 us is better
than, say, 2 or 3?
[...]
> @@ -520,6 +538,17 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
> if (ret)
> goto free;
>
>
>
>
> + if (host->mmc->caps & MMC_CAP_HW_RESET) {
> + priv->rst_hw = devm_reset_control_get_optional_exclusive(dev, "hw");
This should be described in cdns,sdhci.yaml first.
regards
Philipp
On 8/22/22 12:03 AM, Philipp Zabel wrote:
> Hi Brad,
>
> On Sa, 2022-08-20 at 12:57 -0700, Brad Larson wrote:
> [...]
>> +static void sdhci_mmc_hw_reset(struct mmc_host *mmc)
>> +{
>> + struct sdhci_host *host = mmc_priv(mmc);
>> + struct sdhci_cdns_priv *priv = sdhci_cdns_priv(host);
>> +
>> + dev_info(mmc_dev(host->mmc), "emmc hardware reset\n");
>> +
>> + reset_control_assert(priv->rst_hw);
>> + /* For eMMC, minimum is 1us but give it 9us for good measure */
>> + udelay(9);
> At a glance, this seems excessive. Is there a reason 9 us is better
> than, say, 2 or 3?
Yes, 3x the minimum should be fine. Changed to 3 usec.
> [...]
>> @@ -520,6 +538,17 @@ static int sdhci_cdns_probe(struct platform_device *pdev)
>> if (ret)
>> goto free;
>>
>>
>>
>>
>> + if (host->mmc->caps & MMC_CAP_HW_RESET) {
>> + priv->rst_hw = devm_reset_control_get_optional_exclusive(dev, "hw");
> This should be described in cdns,sdhci.yaml first.
Adding this to cdns,sdhci.yaml and running through schema checker.
--- a/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
+++ b/Documentation/devicetree/bindings/mmc/cdns,sdhci.yaml
@@ -114,6 +114,16 @@ properties:
minimum: 0
maximum: 0x7f
+ reset-names:
+ items:
+ - const: hw
+
+ resets:
+ description:
+ optional. phandle to the system reset controller with line index
+ for mmc hw reset line if exists.
+ maxItems: 1
+
required:
- compatible
Regards,
Brad
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