[PATCH 0/3] mmc: sunxi: Support eMMC DDR modes

[PATCH 0/3] mmc: sunxi: Support eMMC DDR modes

[Chen-Yu Tsai]

Hi everyone,

This was "mmc: sunxi: Support vqmmc regulator and eMMC DDR modes". vqmmc
support and DT patches were merged even though it was an RFC series, to
my suprise.

These are the remaining patches that add eMMC HS-DDR support to sunxi.

Patch 1 adds timing delays for MMC_DDR52 mode.

Patch 2 adds support for 8 bit eMMC DDR52 mode. Under this mode, the
controller must run at twice the card clock, and different timing delays
are needed.

Patch 3 enables eMMC HS-DDR for sunxi-mmc.


Changes since RFC:

  - Dropped patches that are merged

  - Dropped "mmc: sunxi: Block signal voltage switching (CMD11)".
    According to Ulf, the mmc core won't send this command unless the UHS
    capabilities are set. We don't.

  - Increased f_max to 52 MHz. Clock rate range for 50 MHz timing delay
    also increased to match. See patch 1.


Regards
ChenYu


Chen-Yu Tsai (3):
  mmc: sunxi: Support MMC_DDR52 timing modes
  mmc: sunxi: Support 8 bit eMMC DDR transfer modes
  mmc: sunxi: Enable eMMC HS-DDR (MMC_CAP_1_8V_DDR) support

 drivers/mmc/host/sunxi-mmc.c | 42 ++++++++++++++++++++++++++++++++----------
 1 file changed, 32 insertions(+), 10 deletions(-)

-- 
2.7.0

[PATCH 1/3] mmc: sunxi: Support MMC_DDR52 timing modes

[Chen-Yu Tsai]

DDR transfer modes include UHS-1 DDR50 and MMC HS-DDR (or MMC_DDR52).
Consider MMC_DDR52 when setting clock delays.

Since MMC high speed mode goes up to 52 MHz instead of 50 MHz for SD,
and this number is visible in the capability macro, increase the
clock rate upper limit to 52 MHz.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 drivers/mmc/host/sunxi-mmc.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index 765dfb9f77ec..fe6c171fd135 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -686,8 +686,9 @@ static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
 	} else if (rate <= 25000000) {
 		oclk_dly = host->clk_delays[SDXC_CLK_25M].output;
 		sclk_dly = host->clk_delays[SDXC_CLK_25M].sample;
-	} else if (rate <= 50000000) {
-		if (ios->timing == MMC_TIMING_UHS_DDR50) {
+	} else if (rate <= 52000000) {
+		if (ios->timing == MMC_TIMING_UHS_DDR50 ||
+		    ios->timing == MMC_TIMING_MMC_DDR52) {
 			oclk_dly = host->clk_delays[SDXC_CLK_50M_DDR].output;
 			sclk_dly = host->clk_delays[SDXC_CLK_50M_DDR].sample;
 		} else {
@@ -762,7 +763,8 @@ static void sunxi_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
 
 	/* set ddr mode */
 	rval = mmc_readl(host, REG_GCTRL);
-	if (ios->timing == MMC_TIMING_UHS_DDR50)
+	if (ios->timing == MMC_TIMING_UHS_DDR50 ||
+	    ios->timing == MMC_TIMING_MMC_DDR52)
 		rval |= SDXC_DDR_MODE;
 	else
 		rval &= ~SDXC_DDR_MODE;
@@ -1106,9 +1108,9 @@ static int sunxi_mmc_probe(struct platform_device *pdev)
 	mmc->max_segs		= PAGE_SIZE / sizeof(struct sunxi_idma_des);
 	mmc->max_seg_size	= (1 << host->idma_des_size_bits);
 	mmc->max_req_size	= mmc->max_seg_size * mmc->max_segs;
-	/* 400kHz ~ 50MHz */
+	/* 400kHz ~ 52MHz */
 	mmc->f_min		=   400000;
-	mmc->f_max		= 50000000;
+	mmc->f_max		= 52000000;
 	mmc->caps	       |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
 				  MMC_CAP_ERASE | MMC_CAP_SDIO_IRQ;
 
-- 
2.7.0

[PATCH 2/3] mmc: sunxi: Support 8 bit eMMC DDR transfer modes

[Chen-Yu Tsai]

Allwinner's MMC controller needs to run at double the card clock rate
for 8 bit DDR transfer modes. Interestingly, this is not needed for
4 bit DDR transfers.

Different clock delays are needed for 8 bit eMMC DDR, due to the
increased module clock rate. For the A80 though, the same values for
4 bit and 8 bit are shared. The new values for the other SoCs were from
A83T user manual's "new timing mode" default values, which describes
them in clock phase, rather than delay periods. These values were used
without any modification. They may not be correct, but they work.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---
 drivers/mmc/host/sunxi-mmc.c | 33 ++++++++++++++++++++++++++-------
 1 file changed, 26 insertions(+), 7 deletions(-)

diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index fe6c171fd135..bb4592696046 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -215,6 +215,7 @@
 #define SDXC_CLK_25M		1
 #define SDXC_CLK_50M		2
 #define SDXC_CLK_50M_DDR	3
+#define SDXC_CLK_50M_DDR_8BIT	4
 
 struct sunxi_mmc_clk_delay {
 	u32 output;
@@ -656,11 +657,17 @@ static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
 				  struct mmc_ios *ios)
 {
 	u32 rate, oclk_dly, rval, sclk_dly;
+	u32 clock = ios->clock;
 	int ret;
 
-	rate = clk_round_rate(host->clk_mmc, ios->clock);
+	/* 8 bit DDR requires a higher module clock */
+	if (ios->timing == MMC_TIMING_MMC_DDR52 &&
+	    ios->bus_width == MMC_BUS_WIDTH_8)
+		clock <<= 1;
+
+	rate = clk_round_rate(host->clk_mmc, clock);
 	dev_dbg(mmc_dev(host->mmc), "setting clk to %d, rounded %d\n",
-		ios->clock, rate);
+		clock, rate);
 
 	/* setting clock rate */
 	ret = clk_set_rate(host->clk_mmc, rate);
@@ -677,6 +684,12 @@ static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
 	/* clear internal divider */
 	rval = mmc_readl(host, REG_CLKCR);
 	rval &= ~0xff;
+	/* set internal divider for 8 bit eMMC DDR, so card clock is right */
+	if (ios->timing == MMC_TIMING_MMC_DDR52 &&
+	    ios->bus_width == MMC_BUS_WIDTH_8) {
+		rval |= 1;
+		rate >>= 1;
+	}
 	mmc_writel(host, REG_CLKCR, rval);
 
 	/* determine delays */
@@ -687,13 +700,16 @@ static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host *host,
 		oclk_dly = host->clk_delays[SDXC_CLK_25M].output;
 		sclk_dly = host->clk_delays[SDXC_CLK_25M].sample;
 	} else if (rate <= 52000000) {
-		if (ios->timing == MMC_TIMING_UHS_DDR50 ||
-		    ios->timing == MMC_TIMING_MMC_DDR52) {
-			oclk_dly = host->clk_delays[SDXC_CLK_50M_DDR].output;
-			sclk_dly = host->clk_delays[SDXC_CLK_50M_DDR].sample;
-		} else {
+		if (ios->timing != MMC_TIMING_UHS_DDR50 &&
+		    ios->timing != MMC_TIMING_MMC_DDR52) {
 			oclk_dly = host->clk_delays[SDXC_CLK_50M].output;
 			sclk_dly = host->clk_delays[SDXC_CLK_50M].sample;
+		} else if (ios->bus_width == MMC_BUS_WIDTH_8) {
+			oclk_dly = host->clk_delays[SDXC_CLK_50M_DDR_8BIT].output;
+			sclk_dly = host->clk_delays[SDXC_CLK_50M_DDR_8BIT].sample;
+		} else {
+			oclk_dly = host->clk_delays[SDXC_CLK_50M_DDR].output;
+			sclk_dly = host->clk_delays[SDXC_CLK_50M_DDR].sample;
 		}
 	} else {
 		return -EINVAL;
@@ -951,6 +967,8 @@ static const struct sunxi_mmc_clk_delay sunxi_mmc_clk_delays[] = {
 	[SDXC_CLK_25M]		= { .output = 180, .sample =  75 },
 	[SDXC_CLK_50M]		= { .output =  90, .sample = 120 },
 	[SDXC_CLK_50M_DDR]	= { .output =  60, .sample = 120 },
+	/* Value from A83T "new timing mode". Works but might not be right. */
+	[SDXC_CLK_50M_DDR_8BIT]	= { .output =  90, .sample = 180 },
 };
 
 static const struct sunxi_mmc_clk_delay sun9i_mmc_clk_delays[] = {
@@ -958,6 +976,7 @@ static const struct sunxi_mmc_clk_delay sun9i_mmc_clk_delays[] = {
 	[SDXC_CLK_25M]		= { .output = 180, .sample =  75 },
 	[SDXC_CLK_50M]		= { .output = 150, .sample = 120 },
 	[SDXC_CLK_50M_DDR]	= { .output =  90, .sample = 120 },
+	[SDXC_CLK_50M_DDR_8BIT]	= { .output =  90, .sample = 120 },
 };
 
 static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
-- 
2.7.0

[PATCH 3/3] mmc: sunxi: Enable eMMC HS-DDR (MMC_CAP_1_8V_DDR) support

[Chen-Yu Tsai]

Now that clock delay settings for 8 bit DDR are correct, and vqmmc
support is available, we can enable MMC_CAP_1_8V_DDR support. This
enables MMC HS-DDR at up to 52 MHz, even if signal voltage switching
is not available.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
---

There was discussion about an alternative: setting this capability
in the DT to preserve DT backwards compatibility. However just setting
it in the DT without the driver updates also breaks it. Furthermore,
Maxime's latest "clk: sunxi: Refactor A31 PLL6 so that it can be reused"
patch will break DT compatility. Given the above, I see no reason to
try and maintain compatibility only to fail.

---
 drivers/mmc/host/sunxi-mmc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index bb4592696046..2aee17cd85ae 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -1131,6 +1131,7 @@ static int sunxi_mmc_probe(struct platform_device *pdev)
 	mmc->f_min		=   400000;
 	mmc->f_max		= 52000000;
 	mmc->caps	       |= MMC_CAP_MMC_HIGHSPEED | MMC_CAP_SD_HIGHSPEED |
+				  MMC_CAP_1_8V_DDR |
 				  MMC_CAP_ERASE | MMC_CAP_SDIO_IRQ;
 
 	ret = mmc_of_parse(mmc);
-- 
2.7.0

[linux-sunxi] [PATCH 0/3] mmc: sunxi: Support eMMC DDR modes

[Hans de Goede]

Hi,

On 01/29/2016 06:21 PM, Chen-Yu Tsai wrote:
> Hi everyone,
>
> This was "mmc: sunxi: Support vqmmc regulator and eMMC DDR modes". vqmmc
> support and DT patches were merged even though it was an RFC series, to
> my suprise.
>
> These are the remaining patches that add eMMC HS-DDR support to sunxi.
>
> Patch 1 adds timing delays for MMC_DDR52 mode.
>
> Patch 2 adds support for 8 bit eMMC DDR52 mode. Under this mode, the
> controller must run at twice the card clock, and different timing delays
> are needed.
>
> Patch 3 enables eMMC HS-DDR for sunxi-mmc.

All 3 patches look good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans

[PATCH 0/3] mmc: sunxi: Support eMMC DDR modes

[Ulf Hansson]

On 29 January 2016 at 18:21, Chen-Yu Tsai <wens@csie.org> wrote:
> Hi everyone,
>
> This was "mmc: sunxi: Support vqmmc regulator and eMMC DDR modes". vqmmc
> support and DT patches were merged even though it was an RFC series, to
> my suprise.
>
> These are the remaining patches that add eMMC HS-DDR support to sunxi.
>
> Patch 1 adds timing delays for MMC_DDR52 mode.
>
> Patch 2 adds support for 8 bit eMMC DDR52 mode. Under this mode, the
> controller must run at twice the card clock, and different timing delays
> are needed.
>
> Patch 3 enables eMMC HS-DDR for sunxi-mmc.
>
>
> Changes since RFC:
>
>   - Dropped patches that are merged
>
>   - Dropped "mmc: sunxi: Block signal voltage switching (CMD11)".
>     According to Ulf, the mmc core won't send this command unless the UHS
>     capabilities are set. We don't.
>
>   - Increased f_max to 52 MHz. Clock rate range for 50 MHz timing delay
>     also increased to match. See patch 1.
>
>
> Regards
> ChenYu
>
>
> Chen-Yu Tsai (3):
>   mmc: sunxi: Support MMC_DDR52 timing modes
>   mmc: sunxi: Support 8 bit eMMC DDR transfer modes
>   mmc: sunxi: Enable eMMC HS-DDR (MMC_CAP_1_8V_DDR) support
>
>  drivers/mmc/host/sunxi-mmc.c | 42 ++++++++++++++++++++++++++++++++----------
>  1 file changed, 32 insertions(+), 10 deletions(-)
>
> --
> 2.7.0
>

Thanks, applied for next!

Kind regards
Uffe