| Message ID | 36180c2b31b154b482892d6c7a3c6d5f386a6a73.1579077085.git.mirq-linux@rere.qmqm.pl (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] mmc: sdhci: fix minimum clock rate for v3 controller | expand |
On 15/01/20 10:32 am, Michał Mirosław wrote: > For SDHCIv3+ with programmable clock mode, minimal clock frequency is > still base clock / max(divider). Minimal programmable clock frequency is > always greater than minimal divided clock frequency. Without this patch, > SDHCI uses out-of-spec initial frequency when multiplier is big enough: > > mmc1: mmc_rescan_try_freq: trying to init card at 468750 Hz > [for 480 MHz source clock divided by 1024] > > The code in sdhci_calc_clk() already chooses a correct SDCLK clock source. source -> mode > > Cc: stable@vger.kernel.org > Fixes: c3ed3877625f ("mmc: sdhci: add support for programmable clock mode") > Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> > --- > v2: extend commitmsg and add comment > --- > drivers/mmc/host/sdhci.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c > index 96609c961465..fde510c55c89 100644 > --- a/drivers/mmc/host/sdhci.c > +++ b/drivers/mmc/host/sdhci.c > @@ -3903,11 +3903,11 @@ int sdhci_setup_host(struct sdhci_host *host) > if (host->ops->get_min_clock) > mmc->f_min = host->ops->get_min_clock(host); > else if (host->version >= SDHCI_SPEC_300) { > - if (host->clk_mul) { > - mmc->f_min = (host->max_clk * host->clk_mul) / 1024; > + if (host->clk_mul) > max_clk = host->max_clk * host->clk_mul; > - } else > - mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300; > + /* minimal divided clock rate is always less than minimal > + * programmable clock rate */ Comment format and let's use the same terminology as the spec. /* * Divided Clock Mode minimum clock rate is always less than * Programmable Clock Mode minimum clock rate. */ > + mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300; > } else > mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_200; > >
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c index 96609c961465..fde510c55c89 100644 --- a/drivers/mmc/host/sdhci.c +++ b/drivers/mmc/host/sdhci.c @@ -3903,11 +3903,11 @@ int sdhci_setup_host(struct sdhci_host *host) if (host->ops->get_min_clock) mmc->f_min = host->ops->get_min_clock(host); else if (host->version >= SDHCI_SPEC_300) { - if (host->clk_mul) { - mmc->f_min = (host->max_clk * host->clk_mul) / 1024; + if (host->clk_mul) max_clk = host->max_clk * host->clk_mul; - } else - mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300; + /* minimal divided clock rate is always less than minimal + * programmable clock rate */ + mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_300; } else mmc->f_min = host->max_clk / SDHCI_MAX_DIV_SPEC_200;
For SDHCIv3+ with programmable clock mode, minimal clock frequency is still base clock / max(divider). Minimal programmable clock frequency is always greater than minimal divided clock frequency. Without this patch, SDHCI uses out-of-spec initial frequency when multiplier is big enough: mmc1: mmc_rescan_try_freq: trying to init card at 468750 Hz [for 480 MHz source clock divided by 1024] The code in sdhci_calc_clk() already chooses a correct SDCLK clock source. Cc: stable@vger.kernel.org Fixes: c3ed3877625f ("mmc: sdhci: add support for programmable clock mode") Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl> --- v2: extend commitmsg and add comment --- drivers/mmc/host/sdhci.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)