On Tue, 12 Jun 2012, Laurent Pinchart wrote:
> The tmio_mmc_set_ios() function configures the MMC power, clock and bus
> width. When the mmc core requests the driver to power off the card, we
> inform runtime PM, that the controller can be suspended. This can lead
> to the MSTP clock being turned off.
>
> Writing to any 16-bit hardware registers with the MSTP clock off leads
> to timeouts and errors being printed to the kernel log. This can occur
> both when stopping the MMC clock and when configuring the bus width.
>
> To fix this, stop the MMC clock before calling put_runtime_pm(), and
> skip bus width configuration when power is off.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Acked-by: Guennadi Liakhovetski <g.liakhovetski@xxxxxx>
Thanks
Guennadi
> ---
> drivers/mmc/host/tmio_mmc_pio.c | 18 ++++++++++--------
> 1 files changed, 10 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mmc/host/tmio_mmc_pio.c b/drivers/mmc/host/tmio_mmc_pio.c
> index 9a7996a..53d1de6 100644
> --- a/drivers/mmc/host/tmio_mmc_pio.c
> +++ b/drivers/mmc/host/tmio_mmc_pio.c
> @@ -810,19 +810,21 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
> if (host->set_pwr && ios->power_mode == MMC_POWER_OFF)
> host->set_pwr(host->pdev, 0);
> if (host->power) {
> + tmio_mmc_clk_stop(host);
> host->power = false;
> pm_runtime_put(dev);
> }
> - tmio_mmc_clk_stop(host);
> }
>
> - switch (ios->bus_width) {
> - case MMC_BUS_WIDTH_1:
> - sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, 0x80e0);
> - break;
> - case MMC_BUS_WIDTH_4:
> - sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, 0x00e0);
> - break;
> + if (host->power) {
> + switch (ios->bus_width) {
> + case MMC_BUS_WIDTH_1:
> + sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, 0x80e0);
> + break;
> + case MMC_BUS_WIDTH_4:
> + sd_ctrl_write16(host, CTL_SD_MEM_CARD_OPT, 0x00e0);
> + break;
> + }
> }
>
> /* Let things settle. delay taken from winCE driver */
> --
> Regards,
>
> Laurent Pinchart
>
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer
http://www.open-technology.de/
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