Re: [PATCH V3 4/7] mmc: sdhci: add 32-bit block count support for v4 mode

From: Chunyan Zhang
Date: Mon Jul 23 2018 - 03:12:19 EST


On 17 July 2018 at 16:29, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> On 09/07/18 06:19, Chunyan Zhang wrote:
>> When Host Version 4 is enabled, SDMA System Address register is
>> re-defined as 32-bit Block Count, and SDMA uses ADMA System
>> Address register (05Fh-058h) instead.
>>
>> Signed-off-by: Chunyan Zhang <zhang.chunyan@xxxxxxxxxx>
>> ---
>> drivers/mmc/host/sdhci.c | 4 +++-
>> drivers/mmc/host/sdhci.h | 1 +
>> 2 files changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index 7871ae2..f64e766 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -889,6 +889,7 @@ static void sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
>> static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
>> {
>> u8 ctrl;
>> + u32 reg;
>> struct mmc_data *data = cmd->data;
>>
>> host->data_timeout = 0;
>> @@ -1021,7 +1022,8 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
>> /* Set the DMA boundary value and block size */
>> sdhci_writew(host, SDHCI_MAKE_BLKSZ(host->sdma_boundary, data->blksz),
>> SDHCI_BLOCK_SIZE);
>> - sdhci_writew(host, data->blocks, SDHCI_BLOCK_COUNT);
>> + reg = host->v4_mode ? SDHCI_32BIT_BLK_CNT : SDHCI_BLOCK_COUNT;
>> + sdhci_writew(host, data->blocks, reg);
>
> The specification says to set 16-bit block count register to zero when using
> 32-bit block count. It also says it is valid for V4.1 onwards and also for

I found that the 16-bit block count register is zero without being
wrriten by driver, and the weird thing on my board is that the
initialization would be interrupted by SDHCI_INT_ADMA_ERROR if setting
"16-bit block count register" to zero manually. So I will add a check
of whether it is zero already before writing it.


> V4 with SDMA and auto-CMD23.
>
> So maybe we should continue to use the 16-bit block count register with V4.0
>
>> }
>>
>> static inline bool sdhci_auto_cmd12(struct sdhci_host *host,
>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>> index 24fa58a..889e48b 100644
>> --- a/drivers/mmc/host/sdhci.h
>> +++ b/drivers/mmc/host/sdhci.h
>> @@ -28,6 +28,7 @@
>>
>> #define SDHCI_DMA_ADDRESS 0x00
>> #define SDHCI_ARGUMENT2 SDHCI_DMA_ADDRESS
>> +#define SDHCI_32BIT_BLK_CNT SDHCI_DMA_ADDRESS
>>
>> #define SDHCI_BLOCK_SIZE 0x04
>> #define SDHCI_MAKE_BLKSZ(dma, blksz) (((dma & 0x7) << 12) | (blksz & 0xFFF))
>>
>