[PATCH] mmc: core: add core-level function for sending tuning commands

[Ulf Hansson]

On 21 November 2014 at 15:46, Barry Song <21cnbao at gmail.com> wrote:
> From: Minda Chen <Minda.Chen at csr.com>
>
> According to the SD card spec, Add a manual tuning command function
> for SDR104/HS200 by sending command 19 or command 21 to read data
> and compare with the tuning block pattern.
>
> this patch will help to decrease some platform private codes in
> SDHCI platform_execute_tuning() callbacks.
>
> Signed-off-by: Minda Chen <Minda.Chen at csr.com>
> Signed-off-by: Barry Song <Baohua.Song at csr.com>
> ---
>  drivers/mmc/core/mmc_ops.c | 65 ++++++++++++++++++++++++++++++++++++++++++++++
>  include/linux/mmc/core.h   |  1 +
>  2 files changed, 66 insertions(+)
>
> diff --git a/drivers/mmc/core/mmc_ops.c b/drivers/mmc/core/mmc_ops.c
> index 7911e05..ecc7789 100644
> --- a/drivers/mmc/core/mmc_ops.c
> +++ b/drivers/mmc/core/mmc_ops.c
> @@ -543,6 +543,71 @@ int mmc_switch(struct mmc_card *card, u8 set, u8 index, u8 value,
>  }
>  EXPORT_SYMBOL_GPL(mmc_switch);
>
> +int mmc_send_tuning(struct mmc_card *card, u32 opcode)
> +{
> +       struct mmc_request mrq = {NULL};
> +       struct mmc_command cmd = {0};
> +       struct mmc_data data = {0};
> +       struct scatterlist sg;
> +       struct mmc_host *mmc = card->host;
> +       struct mmc_ios *ios = &mmc->ios;
> +       const u8 *tuning_block_pattern;
> +       int size, err = 0;
> +       u8 *data_buf;
> +
> +       if (opcode == MMC_SEND_TUNING_BLOCK_HS200) {

I don't think we need to care about the opcode. Let's just check the bus_width.

> +               if (ios->bus_width == MMC_BUS_WIDTH_8) {
> +                       tuning_block_pattern = tuning_blk_pattern_8bit;
> +                       size = sizeof(tuning_blk_pattern_8bit);
> +               } else if (ios->bus_width == MMC_BUS_WIDTH_4) {
> +                       tuning_block_pattern = tuning_blk_pattern_4bit;
> +                       size = sizeof(tuning_blk_pattern_4bit);
> +               } else
> +                       return -EINVAL;
> +       } else if (opcode == MMC_SEND_TUNING_BLOCK) {
> +               tuning_block_pattern = tuning_blk_pattern_4bit;
> +               size = sizeof(tuning_blk_pattern_4bit);
> +       } else
> +               return -EINVAL;
> +
> +       data_buf = kmalloc(size, GFP_KERNEL);

You should use kzalloc() to get the zeroed buffer you want.

> +       if (!data_buf)
> +               return -ENOMEM;
> +
> +       mrq.cmd = &cmd;
> +       mrq.data = &data;
> +
> +       cmd.opcode = opcode;
> +       cmd.flags = MMC_RSP_R1 | MMC_CMD_ADTC;
> +
> +       data.blksz = size;
> +       data.blocks = 1;
> +       data.flags = MMC_DATA_READ;

These needs to be assigned as well:

data.sg = &sg;
data.sg_len = 1;

> +
> +       mmc_set_data_timeout(&data, card);

mmc_set_data_timeout() doesn't handle CMD21/19.

The specs tells us about 40 commands should be executed within 150ms.
I would pick a value of 150ms, just to be sure we are inside that
range. Also, assign "data->timeout_ns" here, instead of relying on
mmc_set_data_timeout().

> +       sg_init_one(&sg, data_buf, size);
> +       memset(data_buf, 0, size);
> +       mmc_wait_for_req(mmc, &mrq);
> +
> +       if (cmd.error) {
> +               err = cmd.error;
> +               goto out;
> +       }
> +
> +       if (data.error) {
> +               err = data.error;
> +               goto out;
> +       }
> +
> +       if (memcmp(data_buf, tuning_block_pattern, size))
> +               err = -EIO;
> +
> +out:
> +       kfree(data_buf);
> +       return err;
> +}
> +EXPORT_SYMBOL_GPL(mmc_send_tuning);
> +
>  static int
>  mmc_send_bus_test(struct mmc_card *card, struct mmc_host *host, u8 opcode,
>                   u8 len)
> diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
> index f206e29..82a0119 100644
> --- a/include/linux/mmc/core.h
> +++ b/include/linux/mmc/core.h
> @@ -154,6 +154,7 @@ extern void mmc_start_bkops(struct mmc_card *card, bool from_exception);
>  extern int __mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int, bool,
>                         bool, bool);
>  extern int mmc_switch(struct mmc_card *, u8, u8, u8, unsigned int);
> +extern int mmc_send_tuning(struct mmc_card *, u32);
>  extern int mmc_send_ext_csd(struct mmc_card *card, u8 *ext_csd);
>
>  #define MMC_ERASE_ARG          0x00000000
> --
> 2.1.1
>

Kind regards
Uffe