Hi Andy,
It's working fine on my environment.
Tested-by: Jaehoon Chung <jh80.ch...@samsung.com>
Best Regards,
Jaehoon Chung
On 11/01/2012 02:02 PM, Andy Fleming wrote:
> At some point, a confusion arose about the use of the bit
> definitions in host_caps for bus widths, and the value
> in ext_csd. By coincidence, a simple shift could convert
> between one and the other:
>
> MMC_MODE_1BIT = 0, EXT_CSD_BUS_WIDTH_1 = 0
> MMC_MODE_4BIT = 0x100, EXT_CSD_BUS_WIDTH_4 = 1
> MMC_MODE_8BIT = 0x200, EXT_CSD_BUS_WIDTH_8 = 2
>
> However, as host_caps is a bitmask of supported things,
> there is not, in fact, a one-to-one correspondence. host_caps
> is capable of containing MODE_4BIT | MODE_8BIT, so nonsensical
> things were happening where we would try to set the bus width
> to 12.
>
> The new code clarifies the very different namespaces:
>
> host_caps/card_caps = bitmask (MMC_MODE_*)
> ext CSD fields are just an index (EXT_CSD_BUS_WIDTH_*)
> mmc->bus_width integer number of bits (1, 4, 8)
>
> We create arrays to map between the namespaces, like in Linux.
>
> Signed-off-by: Andy Fleming <aflem...@freescale.com>
> ---
>
> This is, I think, the approach we should use to identify the
> proper bus width for an mmc device. Please review and/or test.
>
>
> drivers/mmc/mmc.c | 47 +++++++++++++++++++++++++++++++++++------------
> 1 file changed, 35 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/mmc/mmc.c b/drivers/mmc/mmc.c
> index 5fbf956..c379a74 100644
> --- a/drivers/mmc/mmc.c
> +++ b/drivers/mmc/mmc.c
> @@ -867,7 +867,7 @@ void mmc_set_bus_width(struct mmc *mmc, uint width)
>
> int mmc_startup(struct mmc *mmc)
> {
> - int err, width;
> + int err;
> uint mult, freq;
> u64 cmult, csize, capacity;
> struct mmc_cmd cmd;
> @@ -1086,21 +1086,44 @@ int mmc_startup(struct mmc *mmc)
> else
> mmc->tran_speed = 25000000;
> } else {
> - width = ((mmc->host_caps & MMC_MODE_MASK_WIDTH_BITS) >>
> - MMC_MODE_WIDTH_BITS_SHIFT);
> - for (; width >= 0; width--) {
> - /* Set the card to use 4 bit*/
> + int idx;
> +
> + /* An array of possible bus widths in order of preference */
> + static unsigned ext_csd_bits[] = {
> + EXT_CSD_BUS_WIDTH_8,
> + EXT_CSD_BUS_WIDTH_4,
> + EXT_CSD_BUS_WIDTH_1,
> + };
> +
> + /* An array to map CSD bus widths to host cap bits */
> + static unsigned ext_to_hostcaps[] = {
> + [EXT_CSD_BUS_WIDTH_4] = MMC_MODE_4BIT,
> + [EXT_CSD_BUS_WIDTH_8] = MMC_MODE_8BIT,
> + };
> +
> + /* An array to map chosen bus width to an integer */
> + static unsigned widths[] = {
> + 8, 4, 1,
> + };
> +
> + for (idx=0; idx < ARRAY_SIZE(ext_csd_bits); idx++) {
> + unsigned int extw = ext_csd_bits[idx];
> +
> + /*
> + * Check to make sure the controller supports
> + * this bus width, if it's more than 1
> + */
> + if (extw != EXT_CSD_BUS_WIDTH_1 &&
> + !(mmc->host_caps &
> ext_to_hostcaps[extw]))
> + continue;
> +
> err = mmc_switch(mmc, EXT_CSD_CMD_SET_NORMAL,
> - EXT_CSD_BUS_WIDTH, width);
> + EXT_CSD_BUS_WIDTH, extw);
>
> if (err)
> continue;
>
> - if (!width) {
> - mmc_set_bus_width(mmc, 1);
> - break;
> - } else
> - mmc_set_bus_width(mmc, 4 * width);
> + mmc_set_bus_width(mmc, widths[idx]);
>
> err = mmc_send_ext_csd(mmc, test_csd);
> if (!err && ext_csd[EXT_CSD_PARTITIONING_SUPPORT] \
> @@ -1114,7 +1137,7 @@ int mmc_startup(struct mmc *mmc)
> && memcmp(&ext_csd[EXT_CSD_SEC_CNT], \
> &test_csd[EXT_CSD_SEC_CNT], 4) == 0) {
>
> - mmc->card_caps |= width;
> + mmc->card_caps |= ext_to_hostcaps[extw];
> break;
> }
> }
>
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