| Message ID | 1453354002-28366-4-git-send-email-wens@csie.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 21 January 2016 at 06:26, Chen-Yu Tsai <wens@csie.org> wrote: > Allwinner's mmc controller supports signal voltage switching. This is > supported in code in Allwinner's kernel. However, publicly available > boards all tie it to a fixed 3.0/3.3V regulator, with options to tie > it to 1.8V for eMMC on some. > > Since Allwinner's kernel is an ancient 3.4, it is hard to say whether > adapting it's code to a modern mainline kernel would work. Block signal > voltage switching until someone has proper hardware to implement and > test this. > > This only affects SD UHS-1 modes, as eMMC switches the voltage directly > without any signaling. > > Signed-off-by: Chen-Yu Tsai <wens@csie.org> > --- > drivers/mmc/host/sunxi-mmc.c | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c > index 790f01662b4e..0495ae7da6d6 100644 > --- a/drivers/mmc/host/sunxi-mmc.c > +++ b/drivers/mmc/host/sunxi-mmc.c > @@ -816,6 +816,20 @@ static void sunxi_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq) > } > } > > + /* > + * TODO Support signal voltage switching > + * > + * Compared to Allwinner's kernel, recent updates in the mmc core > + * mean this should be as easy as setting the flags in cmd_val and > + * imask, and waiting for it to finish. However no boards support > + * this so this cannot be tested. Block it for now. > + */ > + if (cmd->opcode == SD_SWITCH_VOLTAGE) { > + mrq->cmd->error = -EPERM; > + mmc_request_done(mmc, mrq); > + return; > + } Unless some of the MMC_CAP_UHS* mode is set, this command shouldn't be sent. So, if you *really* want to protect from this, I think it's better to clear these caps in the ->probe() function, after mmc_of_parse() has been called. > + > if (cmd->opcode == MMC_GO_IDLE_STATE) { > cmd_val |= SDXC_SEND_INIT_SEQUENCE; > imask |= SDXC_COMMAND_DONE; > -- > 2.7.0.rc3 > Kind regards Uffe
On Fri, Jan 29, 2016 at 6:42 PM, Ulf Hansson <ulf.hansson@linaro.org> wrote: > On 21 January 2016 at 06:26, Chen-Yu Tsai <wens@csie.org> wrote: >> Allwinner's mmc controller supports signal voltage switching. This is >> supported in code in Allwinner's kernel. However, publicly available >> boards all tie it to a fixed 3.0/3.3V regulator, with options to tie >> it to 1.8V for eMMC on some. >> >> Since Allwinner's kernel is an ancient 3.4, it is hard to say whether >> adapting it's code to a modern mainline kernel would work. Block signal >> voltage switching until someone has proper hardware to implement and >> test this. >> >> This only affects SD UHS-1 modes, as eMMC switches the voltage directly >> without any signaling. >> >> Signed-off-by: Chen-Yu Tsai <wens@csie.org> >> --- >> drivers/mmc/host/sunxi-mmc.c | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c >> index 790f01662b4e..0495ae7da6d6 100644 >> --- a/drivers/mmc/host/sunxi-mmc.c >> +++ b/drivers/mmc/host/sunxi-mmc.c >> @@ -816,6 +816,20 @@ static void sunxi_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq) >> } >> } >> >> + /* >> + * TODO Support signal voltage switching >> + * >> + * Compared to Allwinner's kernel, recent updates in the mmc core >> + * mean this should be as easy as setting the flags in cmd_val and >> + * imask, and waiting for it to finish. However no boards support >> + * this so this cannot be tested. Block it for now. >> + */ >> + if (cmd->opcode == SD_SWITCH_VOLTAGE) { >> + mrq->cmd->error = -EPERM; >> + mmc_request_done(mmc, mrq); >> + return; >> + } > > Unless some of the MMC_CAP_UHS* mode is set, this command shouldn't be sent. > > So, if you *really* want to protect from this, I think it's better to > clear these caps in the ->probe() function, after mmc_of_parse() has > been called. OK. If we need to block these, then we need to block all the other unsupported caps, which seems excessive and unnecessary. I'll drop this patch. Thanks ChenYu > >> + >> if (cmd->opcode == MMC_GO_IDLE_STATE) { >> cmd_val |= SDXC_SEND_INIT_SEQUENCE; >> imask |= SDXC_COMMAND_DONE; >> -- >> 2.7.0.rc3 >> > > Kind regards > Uffe
diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c index 790f01662b4e..0495ae7da6d6 100644 --- a/drivers/mmc/host/sunxi-mmc.c +++ b/drivers/mmc/host/sunxi-mmc.c @@ -816,6 +816,20 @@ static void sunxi_mmc_request(struct mmc_host *mmc, struct mmc_request *mrq) } } + /* + * TODO Support signal voltage switching + * + * Compared to Allwinner's kernel, recent updates in the mmc core + * mean this should be as easy as setting the flags in cmd_val and + * imask, and waiting for it to finish. However no boards support + * this so this cannot be tested. Block it for now. + */ + if (cmd->opcode == SD_SWITCH_VOLTAGE) { + mrq->cmd->error = -EPERM; + mmc_request_done(mmc, mrq); + return; + } + if (cmd->opcode == MMC_GO_IDLE_STATE) { cmd_val |= SDXC_SEND_INIT_SEQUENCE; imask |= SDXC_COMMAND_DONE;
Allwinner's mmc controller supports signal voltage switching. This is supported in code in Allwinner's kernel. However, publicly available boards all tie it to a fixed 3.0/3.3V regulator, with options to tie it to 1.8V for eMMC on some. Since Allwinner's kernel is an ancient 3.4, it is hard to say whether adapting it's code to a modern mainline kernel would work. Block signal voltage switching until someone has proper hardware to implement and test this. This only affects SD UHS-1 modes, as eMMC switches the voltage directly without any signaling. Signed-off-by: Chen-Yu Tsai <wens@csie.org> --- drivers/mmc/host/sunxi-mmc.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+)