| From d4d11449088ee9aca16fd1884b852b8b73a4bda1 Mon Sep 17 00:00:00 2001 |
| From: Stephen Warren <swarren@nvidia.com> |
| Date: Mon, 22 Sep 2014 09:57:42 -0600 |
| Subject: mmc: don't request CD IRQ until mmc_start_host() |
| |
| From: Stephen Warren <swarren@nvidia.com> |
| |
| commit d4d11449088ee9aca16fd1884b852b8b73a4bda1 upstream. |
| |
| As soon as the CD IRQ is requested, it can trigger, since it's an |
| externally controlled event. If it does, delayed_work host->detect will |
| be scheduled. |
| |
| Many host controller probe()s are roughly structured as: |
| |
| *_probe() { |
| host = sdhci_pltfm_init(); |
| mmc_of_parse(host->mmc); |
| rc = sdhci_add_host(host); |
| if (rc) { |
| sdhci_pltfm_free(); |
| return rc; |
| } |
| |
| In 3.17, CD IRQs can are enabled quite early via *_probe() -> |
| mmc_of_parse() -> mmc_gpio_request_cd() -> mmc_gpiod_request_cd_irq(). |
| |
| Note that in linux-next, mmc_of_parse() calls mmc_gpio*d*_request_cd() |
| rather than mmc_gpio_request_cd(), and mmc_gpio*d*_request_cd() doesn't |
| call mmc_gpiod_request_cd_irq(). However, this issue still exists if |
| mmc_gpio_request_cd() is called directly before mmc_start_host(). |
| |
| sdhci_add_host() may fail part way through (e.g. due to deferred |
| probe for a vmmc regulator), and sdhci_pltfm_free() does nothing to |
| unrequest the CD IRQ nor cancel the delayed_work. sdhci_pltfm_free() is |
| coded to assume that if sdhci_add_host() failed, then the delayed_work |
| cannot (or should not) have been triggered. |
| |
| This can lead to the following with CONFIG_DEBUG_OBJECTS_* enabled, when |
| kfree(host) is eventually called inside sdhci_pltfm_free(): |
| |
| WARNING: CPU: 2 PID: 6 at lib/debugobjects.c:263 debug_print_object+0x8c/0xb4() |
| ODEBUG: free active (active state 0) object type: timer_list hint: delayed_work_timer_fn+0x0/0x18 |
| |
| The object being complained about is host->detect. |
| |
| There's no need to request the CD IRQ so early; mmc_start_host() already |
| requests it. For most SDHCI hosts at least, the typical call path that |
| does this is: *_probe() -> sdhci_add_host() -> mmc_add_host() -> |
| mmc_start_host(). Therefore, remove the call to mmc_gpiod_request_cd_irq() |
| from mmc_gpio_request_cd(). This also matches mmc_gpio*d*_request_cd(), |
| which already doesn't call mmc_gpiod_request_cd_irq(). |
| |
| However, some host controller drivers call mmc_gpio_request_cd() after |
| mmc_start_host() has already been called, and assume that this will also |
| call mmc_gpiod_request_cd_irq(). Update those drivers to explicitly call |
| mmc_gpiod_request_cd_irq() themselves. Ideally, these drivers should be |
| modified to move their call to mmc_gpio_request_cd() before their call |
| to mmc_add_host(). However that's too large a change for stable. |
| |
| This solves the problem (eliminates the kernel error message above), |
| since it guarantees that the IRQ can't trigger before mmc_start_host() |
| is called. |
| |
| The critical point here is that once sdhci_add_host() calls |
| mmc_add_host() -> mmc_start_host(), sdhci_add_host() is coded not to |
| fail. In other words, if there's a chance that mmc_start_host() may have |
| been called, and CD IRQs triggered, and the delayed_work scheduled, |
| sdhci_add_host() won't fail, and so cleanup is no longer via |
| sdhci_pltfm_free() (which doesn't free the IRQ or cancel the work queue) |
| but instead must be via sdhci_remove_host(), which calls mmc_remove_host() |
| -> mmc_stop_host(), which does free the IRQ and cancel the work queue. |
| |
| CC: Russell King <linux@arm.linux.org.uk> |
| Cc: Adrian Hunter <adrian.hunter@intel.com> |
| Cc: Alexandre Courbot <acourbot@nvidia.com> |
| Cc: Linus Walleij <linus.walleij@linaro.org> |
| Signed-off-by: Stephen Warren <swarren@nvidia.com> |
| Acked-by: Adrian Hunter <adrian.hunter@intel.com> |
| Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org> |
| Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| |
| --- |
| drivers/mmc/core/slot-gpio.c | 2 -- |
| drivers/mmc/host/mmc_spi.c | 1 + |
| drivers/mmc/host/sdhci-sirf.c | 1 + |
| drivers/mmc/host/tmio_mmc_pio.c | 1 + |
| 4 files changed, 3 insertions(+), 2 deletions(-) |
| |
| --- a/drivers/mmc/core/slot-gpio.c |
| +++ b/drivers/mmc/core/slot-gpio.c |
| @@ -221,8 +221,6 @@ int mmc_gpio_request_cd(struct mmc_host |
| ctx->override_cd_active_level = true; |
| ctx->cd_gpio = gpio_to_desc(gpio); |
| |
| - mmc_gpiod_request_cd_irq(host); |
| - |
| return 0; |
| } |
| EXPORT_SYMBOL(mmc_gpio_request_cd); |
| --- a/drivers/mmc/host/mmc_spi.c |
| +++ b/drivers/mmc/host/mmc_spi.c |
| @@ -1436,6 +1436,7 @@ static int mmc_spi_probe(struct spi_devi |
| host->pdata->cd_debounce); |
| if (status != 0) |
| goto fail_add_host; |
| + mmc_gpiod_request_cd_irq(mmc); |
| } |
| |
| if (host->pdata && host->pdata->flags & MMC_SPI_USE_RO_GPIO) { |
| --- a/drivers/mmc/host/sdhci-sirf.c |
| +++ b/drivers/mmc/host/sdhci-sirf.c |
| @@ -94,6 +94,7 @@ static int sdhci_sirf_probe(struct platf |
| ret); |
| goto err_request_cd; |
| } |
| + mmc_gpiod_request_cd_irq(host->mmc); |
| } |
| |
| return 0; |
| --- a/drivers/mmc/host/tmio_mmc_pio.c |
| +++ b/drivers/mmc/host/tmio_mmc_pio.c |
| @@ -1103,6 +1103,7 @@ int tmio_mmc_host_probe(struct tmio_mmc_ |
| tmio_mmc_host_remove(_host); |
| return ret; |
| } |
| + mmc_gpiod_request_cd_irq(mmc); |
| } |
| |
| *host = _host; |