Re: [RFC PATCH 1/2] mmc: sdhci: add quirk SDHCI_QUIRK2_BROKEN_SDMA_BOUNDARY_BUFFER

From: Ulf Hansson
Date: Tue Jul 11 2017 - 09:49:58 EST


On 28 June 2017 at 15:35, <srinivas.kandagatla@xxxxxxxxxx> wrote:
> From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
>
> 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@xxxxxxxxxx>
> ---
> 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?

Kind regards
Uffe