| Message ID | 1586835611-13857-4-git-send-email-yong.mao@mediatek.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [1/3] mmc: core: need do mmc_power_cycle in mmc_sdio_resend_if_cond | expand |
Hi Yong, On Tue, Apr 14, 2020 at 11:40:11AM +0800, Yong Mao wrote: > From: yong mao <yong.mao@mediatek.com> > > If SDIO device is initialized by UHS mode, it will run with 1.8v power. > In this mode, mmc_go_idle may not make SDIO device go idle successfully > in some special SDIO device. And then it can't be re-initialized > successfully. > According to the logic in sdio_reset_comm and mmc_sdio_sw_reset, > invoking mmc_set_clock(host, host->f_min) before mmc_send_io_op_cond > can make this SDIO device back to right state. > The commit message isn't very concise. Suggestion for a better structure: mmc: core: reset clock to minimum speed during card reinit Some buggy (?) SDIO devices don't (consistently?) enter idle mode through mmc_go_idle() when running in UHS mode. [add rationale why setting the clock to minimum speed fixes this] Also the function sdio_reset_comm() mentioned in the commit message doesn't exist in recent kernels. And mmc_sdio_sw_reset() does not invoke mmc_send_io_op_cond(), as the commit message appears to claim. > Signed-off-by: Yong Mao <yong.mao@mediatek.com> > --- > drivers/mmc/core/sdio.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c > index f173cad..dc4dc63 100644 > --- a/drivers/mmc/core/sdio.c > +++ b/drivers/mmc/core/sdio.c > @@ -850,6 +850,7 @@ static int mmc_sdio_reinit_card(struct mmc_host *host) > > sdio_reset(host); > mmc_go_idle(host); > + mmc_set_clock(host, host->f_min); mmc_sdio_sw_reset() - which is mentioned as reference in the commit message - sets the clock speed before sdio_reset(). Should this order be followed here too?
diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c index f173cad..dc4dc63 100644 --- a/drivers/mmc/core/sdio.c +++ b/drivers/mmc/core/sdio.c @@ -850,6 +850,7 @@ static int mmc_sdio_reinit_card(struct mmc_host *host) sdio_reset(host); mmc_go_idle(host); + mmc_set_clock(host, host->f_min); mmc_send_if_cond(host, host->card->ocr); ret = mmc_send_io_op_cond(host, 0, NULL);