Re: [linux-sunxi] Re: [PATCH] mmc: sunxi: Fix clk-delay settings

[Hans de Goede]

Hi,

On 23-09-15 23:50, Ulf Hansson wrote:

On 23 September 2015 at 22:06, Hans de Goede <hdego...@redhat.com> wrote:

In recent allwinner kernel sources the mmc clk-delay settings have been
slightly tweaked, and for sun9i they are completely different then what
we are using.

This commit brings us in sync with what allwinner does, fixing problems
accessing sdcards on some A33 devices (and likely others).

For pre sun9i hardware this makes the following changes:
-At 400Khz change the sample delay from 7 to 0 (introduced in A31 sdk)
-At 50 Mhz change the sample delay from 5 to 4 (introduced in A23 sdk)

This also drops the clk-delay calculation for clocks > 50 MHz, we do
not need this as we've: mmc->f_max = 50000000, and the delays in the
old code were not correct (at 100 MHz the delay must be a multiple of 60,
at 200 MHz a multiple of 120).

Signed-off-by: Hans de Goede <hdego...@redhat.com>

I assume you want me to take this as a fix?

With that you mean take it into 4.3-rcX ? Yes please.

If so, can we point to what commit it fixes?

Erm, the clk-sample settings this adjusts have been there more or less
unchanged since the driver was introduced, and were taken directly from
the allwinner A10 kernel source / SDK.

This just syncs them with improvements done to the settings in later
allwinner SDK-s, improvements which I found when I could not get multiple
cards to work on certain A33 based tablets.

Regards,

Hans

---
  drivers/mmc/host/sunxi-mmc.c | 53 ++++++++++++++++++++++++++++++++------------
  1 file changed, 39 insertions(+), 14 deletions(-)

diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
index e6226cd..83de82b 100644
--- a/drivers/mmc/host/sunxi-mmc.c
+++ b/drivers/mmc/host/sunxi-mmc.c
@@ -210,6 +210,16 @@
  #define SDXC_IDMAC_DES0_CES    BIT(30) /* card error summary */
  #define SDXC_IDMAC_DES0_OWN    BIT(31) /* 1-idma owns it, 0-host owns it */

+#define SDXC_CLK_400K          0
+#define SDXC_CLK_25M           1
+#define SDXC_CLK_50M           2
+#define SDXC_CLK_50M_DDR       3
+
+struct sunxi_mmc_clk_delay {
+       u32 output;
+       u32 sample;
+};
+
  struct sunxi_idma_des {
         u32     config;
         u32     buf_size;
@@ -229,6 +239,7 @@ struct sunxi_mmc_host {
         struct clk      *clk_mmc;
         struct clk      *clk_sample;
         struct clk      *clk_output;
+       const struct sunxi_mmc_clk_delay *clk_delays;

         /* irq */
         spinlock_t      lock;
@@ -654,25 +665,19 @@ static int sunxi_mmc_clk_set_rate(struct sunxi_mmc_host 
*host,

         /* determine delays */
         if (rate <= 400000) {
-               oclk_dly = 180;
-               sclk_dly = 42;
+               oclk_dly = host->clk_delays[SDXC_CLK_400K].output;
+               sclk_dly = host->clk_delays[SDXC_CLK_400K].sample;
         } else if (rate <= 25000000) {
-               oclk_dly = 180;
-               sclk_dly = 75;
+               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) {
-                       oclk_dly = 60;
-                       sclk_dly = 120;
+                       oclk_dly = host->clk_delays[SDXC_CLK_50M_DDR].output;
+                       sclk_dly = host->clk_delays[SDXC_CLK_50M_DDR].sample;
                 } else {
-                       oclk_dly = 90;
-                       sclk_dly = 150;
+                       oclk_dly = host->clk_delays[SDXC_CLK_50M].output;
+                       sclk_dly = host->clk_delays[SDXC_CLK_50M].sample;
                 }
-       } else if (rate <= 100000000) {
-               oclk_dly = 6;
-               sclk_dly = 24;
-       } else if (rate <= 200000000) {
-               oclk_dly = 3;
-               sclk_dly = 12;
         } else {
                 return -EINVAL;
         }
@@ -878,6 +883,7 @@ static int sunxi_mmc_card_busy(struct mmc_host *mmc)
  static const struct of_device_id sunxi_mmc_of_match[] = {
         { .compatible = "allwinner,sun4i-a10-mmc", },
         { .compatible = "allwinner,sun5i-a13-mmc", },
+       { .compatible = "allwinner,sun9i-a80-mmc", },
         { /* sentinel */ }
  };
  MODULE_DEVICE_TABLE(of, sunxi_mmc_of_match);
@@ -892,6 +898,20 @@ static struct mmc_host_ops sunxi_mmc_ops = {
         .card_busy       = sunxi_mmc_card_busy,
  };

+static const struct sunxi_mmc_clk_delay sunxi_mmc_clk_delays[] = {
+       [SDXC_CLK_400K]         = { .output = 180, .sample = 180 },
+       [SDXC_CLK_25M]          = { .output = 180, .sample =  75 },
+       [SDXC_CLK_50M]          = { .output =  90, .sample = 120 },
+       [SDXC_CLK_50M_DDR]      = { .output =  60, .sample = 120 },
+};
+
+static const struct sunxi_mmc_clk_delay sun9i_mmc_clk_delays[] = {
+       [SDXC_CLK_400K]         = { .output = 180, .sample = 180 },
+       [SDXC_CLK_25M]          = { .output = 180, .sample =  75 },
+       [SDXC_CLK_50M]          = { .output = 150, .sample = 120 },
+       [SDXC_CLK_50M_DDR]      = { .output =  90, .sample = 120 },
+};
+
  static int sunxi_mmc_resource_request(struct sunxi_mmc_host *host,
                                       struct platform_device *pdev)
  {
@@ -903,6 +923,11 @@ static int sunxi_mmc_resource_request(struct 
sunxi_mmc_host *host,
         else
                 host->idma_des_size_bits = 16;

+       if (of_device_is_compatible(np, "allwinner,sun9i-a80-mmc"))
+               host->clk_delays = sun9i_mmc_clk_delays;
+       else
+               host->clk_delays = sunxi_mmc_clk_delays;
+
         ret = mmc_regulator_get_supply(host->mmc);
         if (ret) {
                 if (ret != -EPROBE_DEFER)
--
2.5.0

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