| Message ID | 1420023250-20671-1-git-send-email-thomas.petazzoni@free-electrons.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 31 December 2014 at 11:54, Thomas Petazzoni <thomas.petazzoni@free-electrons.com> wrote: > In commit 5491ce3f79ee ("mmc: sdhci-pxav3: add support for the Armada > 38x SDHCI controller"), the sdhci-pxav3 driver was extended to include > support for the SDHCI controller found in the Armada 38x > processor. This mainly involved adding some MBus window related > configuration. > > However, this configuration is currently done too early in ->probe(): > it is done before clocks are enabled, while this configuration > involves touching the registers of the controller, which will hang the > SoC if the clock is disabled. It wasn't noticed until now because the > bootloader typically leaves gatable clocks enabled, but in situations > where we have a deferred probe (due to a CD GPIO that cannot be taken, > for example), then the probe will be re-tried later, after a clock > disable has been done in the exit path of the failed probe attempt of > the device. This second probe() will hang the system due to the clock > being disabled. > > This can for example be produced on Armada 385 GP, which has a CD GPIO > connected to an I2C PCA9555. If the driver for the PCA9555 is not > compiled into the kernel, then we will have the following sequence of > events: > > 1. The SDHCI probes > 2. It does the MBus configuration (which works, because the clock is > left enabled by the bootloader) > 3. It enables the clock > 4. It tries to get the CD GPIO, which fails due to the driver being > missing, so -EPROBE_DEFER is returned. > 5. Before returning -EPROBE_DEFER, the driver cleans up what was > done, which includes disabling the clock. > 6. Later on, the SDHCI probe is tried again. > 7. It does the MBus configuration, which hangs because the clock is > no longer enabled. > > This commit does the obvious fix of doing the MBus configuration after > the clock has been enabled by the driver. > > Fixes: 5491ce3f79ee ("mmc: sdhci-pxav3: add support for the Armada 38x SDHCI controller") > Cc: <stable@vger.kernel.org> # v3.15+ > Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Thanks! Applied for fixes. Kind regards Uffe > --- > drivers/mmc/host/sdhci-pxav3.c | 15 +++++++-------- > 1 file changed, 7 insertions(+), 8 deletions(-) > > diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c > index 4523887..ca3424e 100644 > --- a/drivers/mmc/host/sdhci-pxav3.c > +++ b/drivers/mmc/host/sdhci-pxav3.c > @@ -300,13 +300,6 @@ static int sdhci_pxav3_probe(struct platform_device *pdev) > if (IS_ERR(host)) > return PTR_ERR(host); > > - if (of_device_is_compatible(np, "marvell,armada-380-sdhci")) { > - ret = mv_conf_mbus_windows(pdev, mv_mbus_dram_info()); > - if (ret < 0) > - goto err_mbus_win; > - } > - > - > pltfm_host = sdhci_priv(host); > pltfm_host->priv = pxa; > > @@ -325,6 +318,12 @@ static int sdhci_pxav3_probe(struct platform_device *pdev) > if (!IS_ERR(pxa->clk_core)) > clk_prepare_enable(pxa->clk_core); > > + if (of_device_is_compatible(np, "marvell,armada-380-sdhci")) { > + ret = mv_conf_mbus_windows(pdev, mv_mbus_dram_info()); > + if (ret < 0) > + goto err_mbus_win; > + } > + > /* enable 1/8V DDR capable */ > host->mmc->caps |= MMC_CAP_1_8V_DDR; > > @@ -396,11 +395,11 @@ err_add_host: > pm_runtime_disable(&pdev->dev); > err_of_parse: > err_cd_req: > +err_mbus_win: > clk_disable_unprepare(pxa->clk_io); > if (!IS_ERR(pxa->clk_core)) > clk_disable_unprepare(pxa->clk_core); > err_clk_get: > -err_mbus_win: > sdhci_pltfm_free(pdev); > return ret; > } > -- > 2.1.0 > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/mmc/host/sdhci-pxav3.c b/drivers/mmc/host/sdhci-pxav3.c index 4523887..ca3424e 100644 --- a/drivers/mmc/host/sdhci-pxav3.c +++ b/drivers/mmc/host/sdhci-pxav3.c @@ -300,13 +300,6 @@ static int sdhci_pxav3_probe(struct platform_device *pdev) if (IS_ERR(host)) return PTR_ERR(host); - if (of_device_is_compatible(np, "marvell,armada-380-sdhci")) { - ret = mv_conf_mbus_windows(pdev, mv_mbus_dram_info()); - if (ret < 0) - goto err_mbus_win; - } - - pltfm_host = sdhci_priv(host); pltfm_host->priv = pxa; @@ -325,6 +318,12 @@ static int sdhci_pxav3_probe(struct platform_device *pdev) if (!IS_ERR(pxa->clk_core)) clk_prepare_enable(pxa->clk_core); + if (of_device_is_compatible(np, "marvell,armada-380-sdhci")) { + ret = mv_conf_mbus_windows(pdev, mv_mbus_dram_info()); + if (ret < 0) + goto err_mbus_win; + } + /* enable 1/8V DDR capable */ host->mmc->caps |= MMC_CAP_1_8V_DDR; @@ -396,11 +395,11 @@ err_add_host: pm_runtime_disable(&pdev->dev); err_of_parse: err_cd_req: +err_mbus_win: clk_disable_unprepare(pxa->clk_io); if (!IS_ERR(pxa->clk_core)) clk_disable_unprepare(pxa->clk_core); err_clk_get: -err_mbus_win: sdhci_pltfm_free(pdev); return ret; }
In commit 5491ce3f79ee ("mmc: sdhci-pxav3: add support for the Armada 38x SDHCI controller"), the sdhci-pxav3 driver was extended to include support for the SDHCI controller found in the Armada 38x processor. This mainly involved adding some MBus window related configuration. However, this configuration is currently done too early in ->probe(): it is done before clocks are enabled, while this configuration involves touching the registers of the controller, which will hang the SoC if the clock is disabled. It wasn't noticed until now because the bootloader typically leaves gatable clocks enabled, but in situations where we have a deferred probe (due to a CD GPIO that cannot be taken, for example), then the probe will be re-tried later, after a clock disable has been done in the exit path of the failed probe attempt of the device. This second probe() will hang the system due to the clock being disabled. This can for example be produced on Armada 385 GP, which has a CD GPIO connected to an I2C PCA9555. If the driver for the PCA9555 is not compiled into the kernel, then we will have the following sequence of events: 1. The SDHCI probes 2. It does the MBus configuration (which works, because the clock is left enabled by the bootloader) 3. It enables the clock 4. It tries to get the CD GPIO, which fails due to the driver being missing, so -EPROBE_DEFER is returned. 5. Before returning -EPROBE_DEFER, the driver cleans up what was done, which includes disabling the clock. 6. Later on, the SDHCI probe is tried again. 7. It does the MBus configuration, which hangs because the clock is no longer enabled. This commit does the obvious fix of doing the MBus configuration after the clock has been enabled by the driver. Fixes: 5491ce3f79ee ("mmc: sdhci-pxav3: add support for the Armada 38x SDHCI controller") Cc: <stable@vger.kernel.org> # v3.15+ Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> --- drivers/mmc/host/sdhci-pxav3.c | 15 +++++++-------- 1 file changed, 7 insertions(+), 8 deletions(-)