Cc: some AMD people
On 1/05/19 8:54 PM, Raul E Rangel wrote:
> AMD SDHC 0x7906 requires a hard reset to clear all internal state.
> Otherwise it can get into a bad state where the DATA lines are always
> read as zeros.
>
> This change requires firmware that can transition the device into
> D3Cold for it to work correctly. If the firmware does not support
> transitioning to D3Cold then the power state transitions are a no-op.
>
> Signed-off-by: Raul E Rangel <rran...@chromium.org>
> ---
>
> drivers/mmc/host/sdhci-pci-core.c | 51 ++++++++++++++++++++++++++++++-
> 1 file changed, 50 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mmc/host/sdhci-pci-core.c
> b/drivers/mmc/host/sdhci-pci-core.c
> index 99b0fec2836b..532fbcbd373b 100644
> --- a/drivers/mmc/host/sdhci-pci-core.c
> +++ b/drivers/mmc/host/sdhci-pci-core.c
> @@ -25,6 +25,7 @@
> #include <linux/mmc/mmc.h>
> #include <linux/scatterlist.h>
> #include <linux/io.h>
> +#include <linux/iopoll.h>
> #include <linux/gpio.h>
> #include <linux/pm_runtime.h>
> #include <linux/mmc/slot-gpio.h>
> @@ -1498,11 +1499,59 @@ static int amd_probe(struct sdhci_pci_chip *chip)
> return 0;
> }
>
> +static u32 sdhci_read_present_state(struct sdhci_host *host)
> +{
> + return sdhci_readl(host, SDHCI_PRESENT_STATE);
> +}
> +
> +void amd_sdhci_reset(struct sdhci_host *host, u8 mask)
> +{
> + struct sdhci_pci_slot *slot = sdhci_priv(host);
> + struct pci_dev *pdev = slot->chip->pdev;
> + u32 present_state;
> +
> + /*
> + * SDHC 0x7906 requires a hard reset to clear all internal state.
> + * Otherwise it can get into a bad state where the DATA lines are always
> + * read as zeros.
> + */
> + if (pdev->device == 0x7906 && (mask & SDHCI_RESET_ALL)) {
> + pci_clear_master(pdev);
> +
> + pci_save_state(pdev);
> +
> + pci_set_power_state(pdev, PCI_D3cold);
> + pr_debug("%s: power_state=%u\n", mmc_hostname(host->mmc),
> + pdev->current_state);
> + pci_set_power_state(pdev, PCI_D0);
> +
> + pci_restore_state(pdev);
> +
> + /*
> + * SDHCI_RESET_ALL says the card detect logic should not be
> + * reset, but since we need to reset the entire controller
> + * we should wait until the card detect logic has stabilized.
> + *
> + * This normally takes about 40ms.
> + */
> + readx_poll_timeout(
> + sdhci_read_present_state,
> + host,
> + present_state,
> + present_state & SDHCI_CD_STABLE,
> + 10000,
> + 100000
> + );
> + }
> +
> + return sdhci_reset(host, mask);
> +}
> +
> static const struct sdhci_ops amd_sdhci_pci_ops = {
> .set_clock = sdhci_set_clock,
> .enable_dma = sdhci_pci_enable_dma,
> .set_bus_width = sdhci_set_bus_width,
> - .reset = sdhci_reset,
> + .reset = amd_sdhci_reset,
> .set_uhs_signaling = sdhci_set_uhs_signaling,
> };
>
>
