Re: [PATCH RFT] mmc: wmt-sdmmc: Fix setting BM_EIGHTBIT_MODE bit in wmt_mci_set_ios()

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On 23/10/13 19:48, Axel Lin wrote:
2013/10/23 Tony Prisk <linux@xxxxxxxxxxxxxxx>:
On 22/10/13 21:54, Axel Lin wrote:
For MMC_BUS_WIDTH_8 case, current code missed setting BM_EIGHTBIT_MODE
bit.
Also has a small refactor to make the code looks better in readability.

So the bit settings witch below logic:

SDMMC_BUSMODE register:
Set EIGHTBIT_MODE bit for 8 bit mode, Set FOURBIT_MODE bit for 4 bit mode.
Clear both EIGHTBIT_MODE and FOURBIT_MODE bits for 1 bit mode.

SDMMC_EXTCTRL register:
Set EXT_EIGHTBIT bit for 8 bit mode, Clear EXT_EIGHTBIT bit for 1/4 bit
mode.

Add define for EXT_EIGHTBIT to avoid using magic number.
BM_ONEBIT_MASK is no longer used, thus remove it.

Signed-off-by: Axel Lin <axel.lin@xxxxxxxxxx>
---
Hi Tony,
After checking wm8505+sdmmc+controller+suppliment.pdf, I'm wondering if
this
dirver works for MMC_BUS_WIDTH_8 case without setting BM_EIGHTBIT_MODE
bit.
I don't have this h/w to test.
I'd appreciate if you can review and test if this patch works.
Thanks,
Axel
   drivers/mmc/host/wmt-sdmmc.c | 31 +++++++++++++++----------------
   1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/drivers/mmc/host/wmt-sdmmc.c b/drivers/mmc/host/wmt-sdmmc.c
index 8a48a50..6ed18f8 100644
--- a/drivers/mmc/host/wmt-sdmmc.c
+++ b/drivers/mmc/host/wmt-sdmmc.c
@@ -72,7 +72,6 @@
   #define BM_SPI_CS                     0x20
   #define BM_SD_POWER                   0x40
   #define BM_SOFT_RESET                 0x80
-#define BM_ONEBIT_MASK                 0xFD
     /* SDMMC_BLKLEN bit fields */
   #define BLKL_CRCERR_ABORT             0x0800
@@ -120,6 +119,8 @@
   #define STS2_DATARSP_BUSY             0x20
   #define STS2_DIS_FORCECLK             0x80
   +/* SDMMC_EXTCTRL bit fields */
+#define EXT_EIGHTBIT                   0x04
     /* MMC/SD DMA Controller Registers */
   #define SDDMA_GCR                     0x100
@@ -672,7 +673,7 @@ static void wmt_mci_request(struct mmc_host *mmc,
struct mmc_request *req)
   static void wmt_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
   {
         struct wmt_mci_priv *priv;
-       u32 reg_tmp;
+       u32 busmode, extctrl;
         priv = mmc_priv(mmc);
   @@ -687,28 +688,26 @@ static void wmt_mci_set_ios(struct mmc_host *mmc,
struct mmc_ios *ios)
         if (ios->clock != 0)
                 clk_set_rate(priv->clk_sdmmc, ios->clock);
   +     busmode = readb(priv->sdmmc_base + SDMMC_BUSMODE);
+       extctrl = readb(priv->sdmmc_base + SDMMC_EXTCTRL);
+
+       busmode &= ~(BM_EIGHTBIT_MODE | BM_FOURBIT_MODE);
+       extctrl &= ~EXT_EIGHTBIT;
+
         switch (ios->bus_width) {
         case MMC_BUS_WIDTH_8:
-               reg_tmp = readb(priv->sdmmc_base + SDMMC_EXTCTRL);
-               writeb(reg_tmp | 0x04, priv->sdmmc_base + SDMMC_EXTCTRL);
+               busmode |= BM_EIGHTBIT_MODE;
+               extctrl |= EXT_EIGHTBIT;
                 break;
         case MMC_BUS_WIDTH_4:
-               reg_tmp = readb(priv->sdmmc_base + SDMMC_BUSMODE);
-               writeb(reg_tmp | BM_FOURBIT_MODE, priv->sdmmc_base +
-                      SDMMC_BUSMODE);
-
-               reg_tmp = readb(priv->sdmmc_base + SDMMC_EXTCTRL);
-               writeb(reg_tmp & 0xFB, priv->sdmmc_base + SDMMC_EXTCTRL);
+               busmode |= BM_FOURBIT_MODE;
                 break;
         case MMC_BUS_WIDTH_1:
-               reg_tmp = readb(priv->sdmmc_base + SDMMC_BUSMODE);
-               writeb(reg_tmp & BM_ONEBIT_MASK, priv->sdmmc_base +
-                      SDMMC_BUSMODE);
-
-               reg_tmp = readb(priv->sdmmc_base + SDMMC_EXTCTRL);
-               writeb(reg_tmp & 0xFB, priv->sdmmc_base + SDMMC_EXTCTRL);
                 break;
         }
+
+       writeb(busmode, priv->sdmmc_base + SDMMC_BUSMODE);
+       writeb(extctrl, priv->sdmmc_base + SDMMC_EXTCTRL);
   }
     static int wmt_mci_get_ro(struct mmc_host *mmc)
I don't have any means of testing this - All the vendor hardware I have uses
4-bit mode.
Oh, well.
But how do you think about this patch?
Since the code is there, and it looks wrong because
wm8505+sdmmc+controller+suppliment.pdf says

SDMMC Ext Control (Offset 0x0034)
BIT2 RW
         0: One Bit / Four bit mode
         1: Eight bit mode

Probably still good to make the code matches the document.

Regards,
Axel
I have no issue with the patch - it seems to make sense in relation to the documentation. I would however suggest that given it is untested, that you perhaps add a note to the header to indicate it as such so no one gets confused down the track if/when there is 8-bit hardware.

Regards
Tony Prisk
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