[PATCH v3 0/3] mmc: support eMMC driver type selection with DT

[PATCH v3 0/3] mmc: support eMMC driver type selection with DT

[Wolfram Sang]

Some of the Renesas R-Car boards need to set the eMMC driver type to type 1 to
get stable HS200/400 speeds (HS400 support not upstream yet). Because the eMMC
memories are fixed (and thus the drive type), I decided to implement the DT
setup in a similar fashion to ACPI [1]. While implementing, I realized that all
I did was not Renesas specific but generic, so I ended up putting it into the
core.

So, whenever the new property (introduced in patch 1) is used, its value will
be used regardless of a potentially implemented host driver specific
select_drive_strength callback (patch 2). An example usage can be found in
patch 3. Note that currently only eMMC is handled

A branch for the Salvator-X(S) boards can be found here:

git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux.git renesas/topic/emmc-drive-strength

A wiki page describing my test procedure can be found here:

http://elinux.org/Tests:eMMC-fixed-drive-strength

Changes since RFC v2 are described per patch. It is mainly a rebase to mmc/next
and addressing Ulf's comments. Tested on Salvator-X (R-Car H3 ES1.0) and
Salvator-XS (R-Car H3 ES2.0).

I know that patch 3 needs to go via Simon, but I still include it here for
completeness.

Thanks,

   Wolfram

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=51ced59cc02e0d08f61772c888480b9b1749cef1


Wolfram Sang (3):
  dt-bindings: mmc: describe new eMMC binding for fixed driver type
  mmc: parse new binding for eMMC fixed driver type
  arm64: renesas: salvator: set driver type for eMMC

 Documentation/devicetree/bindings/mmc/mmc.txt    |  3 +++
 arch/arm64/boot/dts/renesas/salvator-common.dtsi |  1 +
 drivers/mmc/core/host.c                          | 13 ++++++++++++-
 drivers/mmc/core/mmc.c                           | 11 ++++++++---
 include/linux/mmc/host.h                         |  2 ++
 5 files changed, 26 insertions(+), 4 deletions(-)

-- 
2.11.0

[PATCH v3 1/3] dt-bindings: mmc: describe new eMMC binding for fixed driver type

[Wolfram Sang]

Some boards may have to use a certain driver type (or drive strength) to
achieve stable eMMC communication. Describe a binding to set this up via
DT.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Rob Herring <robh@kernel.org>
---

no changes since v2

 Documentation/devicetree/bindings/mmc/mmc.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
index b32ade645ad97c..94a90b49a6925d 100644
--- a/Documentation/devicetree/bindings/mmc/mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc.txt
@@ -53,6 +53,9 @@ Optional properties:
 - no-sdio: controller is limited to send sdio cmd during initialization
 - no-sd: controller is limited to send sd cmd during initialization
 - no-mmc: controller is limited to send mmc cmd during initialization
+- fixed-emmc-driver-type: for non-removable eMMC, enforce this driver type.
+  The value <n> is the driver type as specified in the eMMC specification
+  (table 206 in spec version 5.1).
 
 *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line
 polarity properties, we have to fix the meaning of the "normal" and "inverted"
-- 
2.11.0

[PATCH v3 2/3] mmc: parse new binding for eMMC fixed driver type

[Wolfram Sang]

Parse the new binding and store it in the host struct after doing some
sanity checks. The code is designed to support fixed SD driver type if
we ever need that.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

Changes since V2:
 * moved from core.c to mmc.c and adapted the code to the new place
 * fixed setting now always has highest priority

 drivers/mmc/core/host.c  | 13 ++++++++++++-
 drivers/mmc/core/mmc.c   | 11 ++++++++---
 include/linux/mmc/host.h |  2 ++
 3 files changed, 22 insertions(+), 4 deletions(-)

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index e58be39b15685e..35a9e4fd1a9f51 100644
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -179,7 +179,7 @@ static void mmc_retune_timer(unsigned long data)
 int mmc_of_parse(struct mmc_host *host)
 {
 	struct device *dev = host->parent;
-	u32 bus_width;
+	u32 bus_width, drv_type;
 	int ret;
 	bool cd_cap_invert, cd_gpio_invert = false;
 	bool ro_cap_invert, ro_gpio_invert = false;
@@ -321,6 +321,15 @@ int mmc_of_parse(struct mmc_host *host)
 	if (device_property_read_bool(dev, "no-mmc"))
 		host->caps2 |= MMC_CAP2_NO_MMC;
 
+	/* Must be after "non-removable" check */
+	if (device_property_read_u32(dev, "fixed-emmc-driver-type", &drv_type) == 0) {
+		if (host->caps & MMC_CAP_NONREMOVABLE)
+			host->fixed_drv_type = drv_type;
+		else
+			dev_err(host->parent,
+				"can't use fixed driver type, media is removable\n");
+	}
+
 	host->dsr_req = !device_property_read_u32(dev, "dsr", &host->dsr);
 	if (host->dsr_req && (host->dsr & ~0xffff)) {
 		dev_err(host->parent,
@@ -393,6 +402,8 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 	host->max_blk_size = 512;
 	host->max_blk_count = PAGE_SIZE / 512;
 
+	host->fixed_drv_type = -EINVAL;
+
 	return host;
 }
 
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 44d67ee8bf7bf2..5e58c5a1508db4 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -1289,13 +1289,18 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
 static void mmc_select_driver_type(struct mmc_card *card)
 {
 	int card_drv_type, drive_strength, drv_type;
+	int fixed_drv_type = card->host->fixed_drv_type;
 
 	card_drv_type = card->ext_csd.raw_driver_strength |
 			mmc_driver_type_mask(0);
 
-	drive_strength = mmc_select_drive_strength(card,
-						   card->ext_csd.hs200_max_dtr,
-						   card_drv_type, &drv_type);
+	if (fixed_drv_type >= 0)
+		drive_strength = card_drv_type & mmc_driver_type_mask(fixed_drv_type)
+				 ? fixed_drv_type : 0;
+	else
+		drive_strength = mmc_select_drive_strength(card,
+							   card->ext_csd.hs200_max_dtr,
+							   card_drv_type, &drv_type);
 
 	card->drive_strength = drive_strength;
 
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index c296f4351c1da4..e7743eca102196 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -354,6 +354,8 @@ struct mmc_host {
 #define MMC_CAP2_CQE		(1 << 23)	/* Has eMMC command queue engine */
 #define MMC_CAP2_CQE_DCMD	(1 << 24)	/* CQE can issue a direct command */
 
+	int			fixed_drv_type;	/* fixed driver type for non-removable media */
+
 	mmc_pm_flag_t		pm_caps;	/* supported pm features */
 
 	/* host specific block data */
-- 
2.11.0

[PATCH v3 3/3] arm64: renesas: salvator: set driver type for eMMC

[Wolfram Sang]

These boards are known to have eMMC issues with the default driver type.
Specify a working one.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---

no changes since v2

 arch/arm64/boot/dts/renesas/salvator-common.dtsi | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/boot/dts/renesas/salvator-common.dtsi b/arch/arm64/boot/dts/renesas/salvator-common.dtsi
index 4786c67b5e6527..215e2d11a0490a 100644
--- a/arch/arm64/boot/dts/renesas/salvator-common.dtsi
+++ b/arch/arm64/boot/dts/renesas/salvator-common.dtsi
@@ -579,6 +579,7 @@
 	bus-width = <8>;
 	mmc-hs200-1_8v;
 	non-removable;
+	fixed-emmc-driver-type = <1>;
 	status = "okay";
 };
 
-- 
2.11.0

Re: [PATCH v3 2/3] mmc: parse new binding for eMMC fixed driver type

[Simon Horman]

On Sun, Oct 15, 2017 at 02:46:14PM +0200, Wolfram Sang wrote:
> Parse the new binding and store it in the host struct after doing some
> sanity checks. The code is designed to support fixed SD driver type if
> we ever need that.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Reviewed-by: Simon Horman <horms+renesas@verge.net.au>

Re: [PATCH v3 1/3] dt-bindings: mmc: describe new eMMC binding for fixed driver type

[Simon Horman]

On Sun, Oct 15, 2017 at 02:46:13PM +0200, Wolfram Sang wrote:
> Some boards may have to use a certain driver type (or drive strength) to
> achieve stable eMMC communication. Describe a binding to set this up via
> DT.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Acked-by: Rob Herring <robh@kernel.org>

Reviewed-by: Simon Horman <horms+renesas@verge.net.au>

Re: [PATCH v3 3/3] arm64: renesas: salvator: set driver type for eMMC

[Simon Horman]

On Sun, Oct 15, 2017 at 02:46:15PM +0200, Wolfram Sang wrote:
> These boards are known to have eMMC issues with the default driver type.
> Specify a working one.
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Hi,

I have marked this as deferred pending acceptance of the bindings.
Please repost or otherwise ping me once that dependency has been accepted.

Re: [PATCH v3 1/3] dt-bindings: mmc: describe new eMMC binding for fixed driver type

[Ulf Hansson]

On 15 October 2017 at 14:46, Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> Some boards may have to use a certain driver type (or drive strength) to
> achieve stable eMMC communication. Describe a binding to set this up via
> DT.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> Acked-by: Rob Herring <robh@kernel.org>

Thanks, applied for next!

Kind regards
Uffe

> ---
>
> no changes since v2
>
>  Documentation/devicetree/bindings/mmc/mmc.txt | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
> index b32ade645ad97c..94a90b49a6925d 100644
> --- a/Documentation/devicetree/bindings/mmc/mmc.txt
> +++ b/Documentation/devicetree/bindings/mmc/mmc.txt
> @@ -53,6 +53,9 @@ Optional properties:
>  - no-sdio: controller is limited to send sdio cmd during initialization
>  - no-sd: controller is limited to send sd cmd during initialization
>  - no-mmc: controller is limited to send mmc cmd during initialization
> +- fixed-emmc-driver-type: for non-removable eMMC, enforce this driver type.
> +  The value <n> is the driver type as specified in the eMMC specification
> +  (table 206 in spec version 5.1).
>
>  *NOTE* on CD and WP polarity. To use common for all SD/MMC host controllers line
>  polarity properties, we have to fix the meaning of the "normal" and "inverted"
> --
> 2.11.0
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v3 2/3] mmc: parse new binding for eMMC fixed driver type

[Ulf Hansson]

On 15 October 2017 at 14:46, Wolfram Sang
<wsa+renesas@sang-engineering.com> wrote:
> Parse the new binding and store it in the host struct after doing some
> sanity checks. The code is designed to support fixed SD driver type if
> we ever need that.
>
> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

Thanks, applied for next!

Kind regards
Uffe

> ---
>
> Changes since V2:
>  * moved from core.c to mmc.c and adapted the code to the new place
>  * fixed setting now always has highest priority
>
>  drivers/mmc/core/host.c  | 13 ++++++++++++-
>  drivers/mmc/core/mmc.c   | 11 ++++++++---
>  include/linux/mmc/host.h |  2 ++
>  3 files changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
> index e58be39b15685e..35a9e4fd1a9f51 100644
> --- a/drivers/mmc/core/host.c
> +++ b/drivers/mmc/core/host.c
> @@ -179,7 +179,7 @@ static void mmc_retune_timer(unsigned long data)
>  int mmc_of_parse(struct mmc_host *host)
>  {
>         struct device *dev = host->parent;
> -       u32 bus_width;
> +       u32 bus_width, drv_type;
>         int ret;
>         bool cd_cap_invert, cd_gpio_invert = false;
>         bool ro_cap_invert, ro_gpio_invert = false;
> @@ -321,6 +321,15 @@ int mmc_of_parse(struct mmc_host *host)
>         if (device_property_read_bool(dev, "no-mmc"))
>                 host->caps2 |= MMC_CAP2_NO_MMC;
>
> +       /* Must be after "non-removable" check */
> +       if (device_property_read_u32(dev, "fixed-emmc-driver-type", &drv_type) == 0) {
> +               if (host->caps & MMC_CAP_NONREMOVABLE)
> +                       host->fixed_drv_type = drv_type;
> +               else
> +                       dev_err(host->parent,
> +                               "can't use fixed driver type, media is removable\n");
> +       }
> +
>         host->dsr_req = !device_property_read_u32(dev, "dsr", &host->dsr);
>         if (host->dsr_req && (host->dsr & ~0xffff)) {
>                 dev_err(host->parent,
> @@ -393,6 +402,8 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
>         host->max_blk_size = 512;
>         host->max_blk_count = PAGE_SIZE / 512;
>
> +       host->fixed_drv_type = -EINVAL;
> +
>         return host;
>  }
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
> index 44d67ee8bf7bf2..5e58c5a1508db4 100644
> --- a/drivers/mmc/core/mmc.c
> +++ b/drivers/mmc/core/mmc.c
> @@ -1289,13 +1289,18 @@ int mmc_hs400_to_hs200(struct mmc_card *card)
>  static void mmc_select_driver_type(struct mmc_card *card)
>  {
>         int card_drv_type, drive_strength, drv_type;
> +       int fixed_drv_type = card->host->fixed_drv_type;
>
>         card_drv_type = card->ext_csd.raw_driver_strength |
>                         mmc_driver_type_mask(0);
>
> -       drive_strength = mmc_select_drive_strength(card,
> -                                                  card->ext_csd.hs200_max_dtr,
> -                                                  card_drv_type, &drv_type);
> +       if (fixed_drv_type >= 0)
> +               drive_strength = card_drv_type & mmc_driver_type_mask(fixed_drv_type)
> +                                ? fixed_drv_type : 0;
> +       else
> +               drive_strength = mmc_select_drive_strength(card,
> +                                                          card->ext_csd.hs200_max_dtr,
> +                                                          card_drv_type, &drv_type);
>
>         card->drive_strength = drive_strength;
>
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index c296f4351c1da4..e7743eca102196 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -354,6 +354,8 @@ struct mmc_host {
>  #define MMC_CAP2_CQE           (1 << 23)       /* Has eMMC command queue engine */
>  #define MMC_CAP2_CQE_DCMD      (1 << 24)       /* CQE can issue a direct command */
>
> +       int                     fixed_drv_type; /* fixed driver type for non-removable media */
> +
>         mmc_pm_flag_t           pm_caps;        /* supported pm features */
>
>         /* host specific block data */
> --
> 2.11.0
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

Re: [PATCH v3 3/3] arm64: renesas: salvator: set driver type for eMMC

[Ulf Hansson]

On 16 October 2017 at 09:46, Simon Horman <horms@verge.net.au> wrote:
> On Sun, Oct 15, 2017 at 02:46:15PM +0200, Wolfram Sang wrote:
>> These boards are known to have eMMC issues with the default driver type.
>> Specify a working one.
>>
>> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
>
> Hi,
>
> I have marked this as deferred pending acceptance of the bindings.
> Please repost or otherwise ping me once that dependency has been accepted.

Simon, I have picked up the bindings, so you may now pick up $subject patch.

Kind regards
Uffe

Re: [PATCH v3 3/3] arm64: renesas: salvator: set driver type for eMMC

[Wolfram Sang]

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> Simon, I have picked up the bindings, so you may now pick up $subject patch.

Thanks, I'll resend this patch to make it super-easy for Simon.


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Re: [PATCH v3 3/3] arm64: renesas: salvator: set driver type for eMMC

[Simon Horman]

On Fri, Oct 20, 2017 at 12:03:16PM +0200, Ulf Hansson wrote:
> On 16 October 2017 at 09:46, Simon Horman <horms@verge.net.au> wrote:
> > On Sun, Oct 15, 2017 at 02:46:15PM +0200, Wolfram Sang wrote:
> >> These boards are known to have eMMC issues with the default driver type.
> >> Specify a working one.
> >>
> >> Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> >
> > Hi,
> >
> > I have marked this as deferred pending acceptance of the bindings.
> > Please repost or otherwise ping me once that dependency has been accepted.
> 
> Simon, I have picked up the bindings, so you may now pick up $subject patch.

Thanks, and sorry for the delay, I have been on holidays.
I have applied this patch.

Re: [PATCH v3 3/3] arm64: renesas: salvator: set driver type for eMMC

[Wolfram Sang]

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> > Simon, I have picked up the bindings, so you may now pick up $subject patch.
> 
> Thanks, and sorry for the delay, I have been on holidays.
> I have applied this patch.

Haha, and I just resent it a second ago :)


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Re: [PATCH v3 3/3] arm64: renesas: salvator: set driver type for eMMC

[Simon Horman]

On Sun, Oct 29, 2017 at 04:23:07PM +0100, Wolfram Sang wrote:
> 
> > > Simon, I have picked up the bindings, so you may now pick up $subject patch.
> > 
> > Thanks, and sorry for the delay, I have been on holidays.
> > I have applied this patch.
> 
> Haha, and I just resent it a second ago :)

Seems that I'm not the only one catching up on things this afternoon :)