On 28/11/22 04:44, Doug Brown wrote:
> The PXA168 has a documented silicon bug that causes SDIO card IRQs to be
> missed. Implement the first half of the suggested workaround, which
> involves resetting the data port logic and issuing a dummy CMD0 to
> restart the clock.
>
> Signed-off-by: Doug Brown <doug@xxxxxxxxxxxxx>
> ---
> drivers/mmc/host/sdhci-pxav2.c | 36 ++++++++++++++++++++++++++++++++++
> 1 file changed, 36 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci-pxav2.c b/drivers/mmc/host/sdhci-pxav2.c
> index 4996d72c6d23..0b9b2e4b2153 100644
> --- a/drivers/mmc/host/sdhci-pxav2.c
> +++ b/drivers/mmc/host/sdhci-pxav2.c
> @@ -20,6 +20,8 @@
> #include <linux/slab.h>
> #include <linux/of.h>
> #include <linux/of_device.h>
> +#include <linux/mmc/sdio.h>
> +#include <linux/mmc/mmc.h>
>
> #include "sdhci.h"
> #include "sdhci-pltfm.h"
> @@ -43,6 +45,7 @@
>
> struct sdhci_pxav2_host {
> struct clk *clk_core;
> + void (*orig_post_req)(struct mmc_host *mmc, struct mmc_request *mrq, int err);
> };
>
> static void pxav2_reset(struct sdhci_host *host, u8 mask)
> @@ -96,6 +99,37 @@ static inline u16 pxav1_readw(struct sdhci_host *host, int reg)
> return readw(host->ioaddr + reg);
> }
>
> +static void pxav1_post_req(struct mmc_host *mmc, struct mmc_request *mrq, int err)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + struct sdhci_pxav2_host *pxav2_host;
> + struct mmc_command dummy_cmd = {};
> + u16 tmp;
> +
> + /* If this is an SDIO command, perform errata workaround for silicon bug. */
> + if (!err && mrq->cmd && !mrq->cmd->error &&
> + (mrq->cmd->opcode == SD_IO_RW_DIRECT ||
> + mrq->cmd->opcode == SD_IO_RW_EXTENDED)) {
> + /* Reset data port */
> + tmp = readw(host->ioaddr + SDHCI_TIMEOUT_CONTROL);
> + tmp |= 0x400;
> + writew(tmp, host->ioaddr + SDHCI_TIMEOUT_CONTROL);
> +
> + /* Clock is now stopped, so restart it by sending a dummy CMD0. */
> + pxav2_host = sdhci_pltfm_priv(sdhci_priv(host));
> +
> + dummy_cmd.opcode = MMC_GO_IDLE_STATE;
> + dummy_cmd.arg = 0;
> + dummy_cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_NONE | MMC_CMD_BC;
> +
> + mmc_wait_for_cmd(host->mmc, &dummy_cmd, 0);
This is not what post_req() is for. Instead could you use SDHCI
host op ->request_done()? Also, do you really need to wait for
the dummy CMD0 - perhaps just write SDHCI_ARGUMENT,
SDHCI_TRANSFER_MODE, and SDHCI_COMMAND ?
> + }
> +
> + /* Pass onto SDHCI host driver now */
> + if (pxav2_host->orig_post_req)
> + pxav2_host->orig_post_req(mmc, mrq, err);
> +}
> +
> static void pxav2_mmc_set_bus_width(struct sdhci_host *host, int width)
> {
> u8 ctrl;
> @@ -252,6 +286,8 @@ static int sdhci_pxav2_probe(struct platform_device *pdev)
> if (match && of_device_is_compatible(dev->of_node, "mrvl,pxav1-mmc")) {
> host->quirks |= SDHCI_QUIRK_NO_BUSY_IRQ | SDHCI_QUIRK_32BIT_DMA_SIZE;
> host->ops = &pxav1_sdhci_ops;
> + pxav2_host->orig_post_req = host->mmc_host_ops.post_req;
> + host->mmc_host_ops.post_req = pxav1_post_req;
> } else {
> host->ops = &pxav2_sdhci_ops;
> }
