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SubjectRe: [RFC PATCH 1/2] mmc: sdhci: add quirk SDHCI_QUIRK2_BROKEN_SDMA_BOUNDARY_BUFFER
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On 11/07/17 16:49, Ulf Hansson wrote:
> On 28 June 2017 at 15:35, <srinivas.kandagatla@linaro.org> wrote:
>> From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>>
>> This patch adds quirk to sdhci controllers which are broken when
>> HOST SDMA Buffer Boundary is programmed in Block Size Register (0x04)
>> when using ADMA. Qualcomm sdhci controller is one of such type, writing
>> to this bits is un-supported.
>>
>> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
>> ---
>> drivers/mmc/host/sdhci.c | 24 ++++++++++++++++++------
>> drivers/mmc/host/sdhci.h | 2 ++
>> 2 files changed, 20 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index ecd0d4350e8a..d68ff1955761 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -765,6 +765,20 @@ static void sdhci_set_timeout(struct sdhci_host *host, struct mmc_command *cmd)
>> }
>> }
>>
>> +static void sdhci_set_blk_size_reg(struct sdhci_host *host,
>> + unsigned int sdma_boundary,
>> + unsigned int blksz)
>> +{
>> + if ((host->quirks2 & SDHCI_QUIRK2_BROKEN_SDMA_BOUNDARY_BUFFER) &&
>> + (host->flags & SDHCI_USE_ADMA)) {
>> + sdhci_writew(host, SDHCI_MAKE_BLKSZ(0, blksz),
>> + SDHCI_BLOCK_SIZE);
>> + } else {
>> + sdhci_writew(host, SDHCI_MAKE_BLKSZ(sdma_boundary, blksz),
>> + SDHCI_BLOCK_SIZE);
>> + }
>> +}
>> +
>> static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
>> {
>> u8 ctrl;
>> @@ -897,8 +911,7 @@ static void sdhci_prepare_data(struct sdhci_host *host, struct mmc_command *cmd)
>> sdhci_set_transfer_irqs(host);
>>
>> /* Set the DMA boundary value and block size */
>> - sdhci_writew(host, SDHCI_MAKE_BLKSZ(SDHCI_DEFAULT_BOUNDARY_ARG,
>> - data->blksz), SDHCI_BLOCK_SIZE);
>> + sdhci_set_blk_size_reg(host, SDHCI_DEFAULT_BOUNDARY_ARG, data->blksz);
>> sdhci_writew(host, data->blocks, SDHCI_BLOCK_COUNT);
>> }
>>
>> @@ -2052,9 +2065,9 @@ static void sdhci_send_tuning(struct sdhci_host *host, u32 opcode)
>> */
>> if (cmd.opcode == MMC_SEND_TUNING_BLOCK_HS200 &&
>> mmc->ios.bus_width == MMC_BUS_WIDTH_8)
>> - sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 128), SDHCI_BLOCK_SIZE);
>> + sdhci_set_blk_size_reg(host, SDHCI_DEFAULT_BOUNDARY_ARG, 128);
>> else
>> - sdhci_writew(host, SDHCI_MAKE_BLKSZ(7, 64), SDHCI_BLOCK_SIZE);
>> + sdhci_set_blk_size_reg(host, SDHCI_DEFAULT_BOUNDARY_ARG, 64);
>>
>> /*
>> * The tuning block is sent by the card to the host controller.
>> @@ -2998,8 +3011,7 @@ void sdhci_cqe_enable(struct mmc_host *mmc)
>> ctrl |= SDHCI_CTRL_ADMA32;
>> sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
>>
>> - sdhci_writew(host, SDHCI_MAKE_BLKSZ(SDHCI_DEFAULT_BOUNDARY_ARG, 512),
>> - SDHCI_BLOCK_SIZE);
>> + sdhci_set_blk_size_reg(host, SDHCI_DEFAULT_BOUNDARY_ARG, 512);
>>
>> /* Set maximum timeout */
>> sdhci_writeb(host, 0xE, SDHCI_TIMEOUT_CONTROL);
>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>> index 0469fa191493..9a1343509bb5 100644
>> --- a/drivers/mmc/host/sdhci.h
>> +++ b/drivers/mmc/host/sdhci.h
>> @@ -435,6 +435,8 @@ struct sdhci_host {
>> #define SDHCI_QUIRK2_ACMD23_BROKEN (1<<14)
>> /* Broken Clock divider zero in controller */
>> #define SDHCI_QUIRK2_CLOCK_DIV_ZERO_BROKEN (1<<15)
>> +/* Controller doesn't support sdma boundray buffer setup when using ADMA */
>> +#define SDHCI_QUIRK2_BROKEN_SDMA_BOUNDARY_BUFFER (1<<16)
>>
>> int irq; /* Device IRQ */
>> void __iomem *ioaddr; /* Mapped address */
>> --
>> 2.11.0
>>
>
> This change seems like a reasonable justification for adding a new
> SDHCI quirk, even if we in general wants to avoid that.
>
> Adrian?

If we add a quirk for every register we end up with a very ugly version of
CONFIG_MMC_SDHCI_IO_ACCESSORS. So CONFIG_MMC_SDHCI_IO_ACCESSORS is a better
option. Another possibility is to add a member to struct sdhci_host,
initialized to SDHCI_DEFAULT_BOUNDARY_ARG, and write that. Drivers could
then change the value if necessary.

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