Skip to content

L
linux
Switch branch/tag
  1. 24 Sep, 2014 2 commits
  3. 23 Sep, 2014 3 commits
    • Stephen Boyd's avatar
      mmc: Consolidate emmc tuning blocks · 48d11e06
      Stephen Boyd authored 
      The same tuning block exists in the dw_mmc h.c and sdhci-msm.c
files. Move these into mmc.c so that they can be shared across
drivers.
Reported-by: default avatarJaehoon Chung <jh80.chung@samsung.com>
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
      48d11e06
    • Stephen Boyd's avatar
      mmc: sdhci-msm: Make tuning block table endian agnostic · ffed1b94
      Stephen Boyd authored 
      If we're tuning on a big-endian CPU we'll never determine we properly
tuned the device because we compare the data we received from the
controller with a table that assumes the CPU is little-endian.
Change the table to be an array of bytes instead of 32-bit words
so we can use memcmp() without needing to byte-swap every word
depending on the endianess of the CPU.

Cc: Asutosh Das <asutoshd@codeaurora.org>
Cc: Venkat Gopalakrishnan <venkatg@codeaurora.org>
Reviewed-by: default avatarGeorgi Djakov <gdjakov@mm-sol.com>
Fixes: 415b5a75 "mmc: sdhci-msm: Add platform_execute_tuning implementation"
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
      ffed1b94
    • Stephen Warren's avatar
      mmc: don't request CD IRQ until mmc_start_host() · d4d11449
      Stephen Warren authored 
      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: default avatarStephen Warren <swarren@nvidia.com>
Acked-by: default avatarAdrian Hunter <adrian.hunter@intel.com>
Cc: <stable@vger.kernel.org> # v3.15+
Signed-off-by: default avatarUlf Hansson <ulf.hansson@linaro.org>
      d4d11449
  5. 19 Sep, 2014 2 commits
  7. 18 Sep, 2014 5 commits
  9. 10 Sep, 2014 3 commits
  11. 09 Sep, 2014 25 commits
GitLab Nexedi Edition | About GitLab | About Nexedi | 沪ICP备2021021310号-2 | 沪ICP备2021021310号-7