| Message ID | 20201210125709.1.Iec3430c7d3c2a29262695edef7b82a14aaa567e5@changeid (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mmc: sdhci-msm: Warn about overclocking SD/MMC | expand |
Quoting Douglas Anderson (2020-12-10 12:57:25) > diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c > index 3451eb325513..dd41f6a4dbfb 100644 > --- a/drivers/mmc/host/sdhci-msm.c > +++ b/drivers/mmc/host/sdhci-msm.c > @@ -353,6 +353,7 @@ static void msm_set_clock_rate_for_bus_mode(struct sdhci_host *host, > struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host); > struct mmc_ios curr_ios = host->mmc->ios; > struct clk *core_clk = msm_host->bulk_clks[0].clk; > + unsigned int achieved_rate; unsigned long? > int rc; > > clock = msm_get_clock_rate_for_bus_mode(host, clock); > @@ -363,6 +364,17 @@ static void msm_set_clock_rate_for_bus_mode(struct sdhci_host *host, > curr_ios.timing); > return; > } > + > + /* > + * Qualcomm clock drivers by default round clock _up_ if they can't > + * make the requested rate. This is not good for SD. Yell if we > + * encounter it. > + */ > + achieved_rate = clk_get_rate(core_clk); > + if (achieved_rate > clock) > + pr_warn("%s: Card appears overclocked; req %u Hz, actual %d Hz\n", Can we use dev_warn? dev_warn(mmc_dev(mmc) dev_warn(&msm_host->pdev->dev ? > + mmc_hostname(host->mmc), clock, achieved_rate); > + > msm_host->clk_rate = clock; > pr_debug("%s: Setting clock at rate %lu at timing %d\n", > mmc_hostname(host->mmc), clk_get_rate(core_clk), This could use achieved_rate now.
Hi, On Thu, Dec 10, 2020 at 1:03 PM Stephen Boyd <swboyd@chromium.org> wrote: > > Quoting Douglas Anderson (2020-12-10 12:57:25) > > diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c > > index 3451eb325513..dd41f6a4dbfb 100644 > > --- a/drivers/mmc/host/sdhci-msm.c > > +++ b/drivers/mmc/host/sdhci-msm.c > > @@ -353,6 +353,7 @@ static void msm_set_clock_rate_for_bus_mode(struct sdhci_host *host, > > struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host); > > struct mmc_ios curr_ios = host->mmc->ios; > > struct clk *core_clk = msm_host->bulk_clks[0].clk; > > + unsigned int achieved_rate; > > unsigned long? I'm matching the type for the parameter. ...but I guess you're right that it's better to match clk_get_rate(). NOTE: I'm _not_ planning to change the parameter because it matches the type in 'struct mmc_ios' and that feels like a much bigger change to tweak. > > int rc; > > > > clock = msm_get_clock_rate_for_bus_mode(host, clock); > > @@ -363,6 +364,17 @@ static void msm_set_clock_rate_for_bus_mode(struct sdhci_host *host, > > curr_ios.timing); > > return; > > } > > + > > + /* > > + * Qualcomm clock drivers by default round clock _up_ if they can't > > + * make the requested rate. This is not good for SD. Yell if we > > + * encounter it. > > + */ > > + achieved_rate = clk_get_rate(core_clk); > > + if (achieved_rate > clock) > > + pr_warn("%s: Card appears overclocked; req %u Hz, actual %d Hz\n", > > Can we use dev_warn? What's here matches other prints including other ones in the same function and in much of the MMC subsystem. mmc_hostname() shows "mmc1" > dev_warn(mmc_dev(mmc) > dev_warn(&msm_host->pdev->dev This show "sdhci_msm 7c4000.sdhci" I'm going to keep with tradition and keep using mmc_hostname(). In some parts of this file they use both (a dev_warn that also includes the mmc_hostname()) but that feels overkill. > ? > > > + mmc_hostname(host->mmc), clock, achieved_rate); > > + > > msm_host->clk_rate = clock; > > pr_debug("%s: Setting clock at rate %lu at timing %d\n", > > mmc_hostname(host->mmc), clk_get_rate(core_clk), > > This could use achieved_rate now. Sure. I sent up a real quick v2 since it seemed like these were small fixes and maybe this was all good otherwise. -Doug
Quoting Doug Anderson (2020-12-10 13:20:03) > On Thu, Dec 10, 2020 at 1:03 PM Stephen Boyd <swboyd@chromium.org> wrote: > > > > > > Can we use dev_warn? > > What's here matches other prints including other ones in the same > function and in much of the MMC subsystem. mmc_hostname() shows > "mmc1" > > > dev_warn(mmc_dev(mmc) > > dev_warn(&msm_host->pdev->dev > > This show "sdhci_msm 7c4000.sdhci" > > I'm going to keep with tradition and keep using mmc_hostname(). In > some parts of this file they use both (a dev_warn that also includes > the mmc_hostname()) but that feels overkill. Ok. This driver should be cleaned up I suppose.
diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c index 3451eb325513..dd41f6a4dbfb 100644 --- a/drivers/mmc/host/sdhci-msm.c +++ b/drivers/mmc/host/sdhci-msm.c @@ -353,6 +353,7 @@ static void msm_set_clock_rate_for_bus_mode(struct sdhci_host *host, struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host); struct mmc_ios curr_ios = host->mmc->ios; struct clk *core_clk = msm_host->bulk_clks[0].clk; + unsigned int achieved_rate; int rc; clock = msm_get_clock_rate_for_bus_mode(host, clock); @@ -363,6 +364,17 @@ static void msm_set_clock_rate_for_bus_mode(struct sdhci_host *host, curr_ios.timing); return; } + + /* + * Qualcomm clock drivers by default round clock _up_ if they can't + * make the requested rate. This is not good for SD. Yell if we + * encounter it. + */ + achieved_rate = clk_get_rate(core_clk); + if (achieved_rate > clock) + pr_warn("%s: Card appears overclocked; req %u Hz, actual %d Hz\n", + mmc_hostname(host->mmc), clock, achieved_rate); + msm_host->clk_rate = clock; pr_debug("%s: Setting clock at rate %lu at timing %d\n", mmc_hostname(host->mmc), clk_get_rate(core_clk),
As talked about in commit 5e4b7e82d497 ("clk: qcom: gcc-sdm845: Use floor ops for sdcc clks"), most clocks handled by the Qualcomm clock drivers are rounded _up_ by default instead of down. We should make sure SD/MMC clocks are always rounded down in the clock drivers. Let's add a warning in the Qualcomm SDHCI driver to help catch the problem. This would have saved a bunch of time [1]. [1] http://lore.kernel.org/r/20201210102234.1.I096779f219625148900fc984dd0084ed1ba87c7f@changeid Suggested-by: Stephen Boyd <swboyd@chromium.org> Signed-off-by: Douglas Anderson <dianders@chromium.org> --- drivers/mmc/host/sdhci-msm.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)