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author | Chen-Yu Tsai <wens@csie.org> | 2016-09-09 11:58:18 +0800 |
---|---|---|
committer | Kishon Vijay Abraham I <kishon@ti.com> | 2016-09-10 17:43:38 +0530 |
commit | 919ab2524c52e5f801d8873f09145ce822cdd43a (patch) | |
tree | bd4c5dfb63234437eb363bfe8b7ac0398dfb3bfe /drivers/phy | |
parent | 0f74ab59ce8712e7e2bb1e4517033328e626b27c (diff) | |
download | linux-919ab2524c52e5f801d8873f09145ce822cdd43a.tar.gz linux-919ab2524c52e5f801d8873f09145ce822cdd43a.tar.bz2 linux-919ab2524c52e5f801d8873f09145ce822cdd43a.zip |
phy: sun4i-usb: Use spinlock to guard phyctl register access
The musb driver calls into this phy driver to disable/enable squelch
detection. This function was introduced in 24fe86a617c5 ("phy: sun4i-usb:
Add a sunxi specific function for setting squelch-detect"). This
function in turn calls sun4i_usb_phy_write, which uses a mutex to
guard the common access register. Unfortunately musb does this
in atomic context, which results in the following warning with lock
debugging enabled:
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:97
in_atomic(): 1, irqs_disabled(): 128, pid: 96, name: kworker/0:2
CPU: 0 PID: 96 Comm: kworker/0:2 Not tainted 4.8.0-rc4-00181-gd502f8ad1c3e #13
Hardware name: Allwinner sun8i Family
Workqueue: events musb_deassert_reset
[<c010bc01>] (unwind_backtrace) from [<c0109237>] (show_stack+0xb/0xc)
[<c0109237>] (show_stack) from [<c02a669b>] (dump_stack+0x67/0x74)
[<c02a669b>] (dump_stack) from [<c05d68c9>] (mutex_lock+0x15/0x2c)
[<c05d68c9>] (mutex_lock) from [<c02c3589>] (sun4i_usb_phy_write+0x39/0xec)
[<c02c3589>] (sun4i_usb_phy_write) from [<c03e6327>] (musb_port_reset+0xfb/0x184)
[<c03e6327>] (musb_port_reset) from [<c03e4917>] (musb_deassert_reset+0x1f/0x2c)
[<c03e4917>] (musb_deassert_reset) from [<c012ecb5>] (process_one_work+0x129/0x2b8)
[<c012ecb5>] (process_one_work) from [<c012f5e3>] (worker_thread+0xf3/0x424)
[<c012f5e3>] (worker_thread) from [<c0132dbd>] (kthread+0xa1/0xb8)
[<c0132dbd>] (kthread) from [<c0105f31>] (ret_from_fork+0x11/0x20)
Since the register access is mmio, we can use a spinlock to guard this
specific access, rather than the mutex that guards the entire phy.
Fixes: ba4bdc9e1dc0 ("PHY: sunxi: Add driver for sunxi usb phy")
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Diffstat (limited to 'drivers/phy')
-rw-r--r-- | drivers/phy/phy-sun4i-usb.c | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/drivers/phy/phy-sun4i-usb.c b/drivers/phy/phy-sun4i-usb.c index 03f030b491d6..b9342a2af7b3 100644 --- a/drivers/phy/phy-sun4i-usb.c +++ b/drivers/phy/phy-sun4i-usb.c @@ -40,6 +40,7 @@ #include <linux/power_supply.h> #include <linux/regulator/consumer.h> #include <linux/reset.h> +#include <linux/spinlock.h> #include <linux/usb/of.h> #include <linux/workqueue.h> @@ -114,7 +115,7 @@ struct sun4i_usb_phy_data { void __iomem *base; const struct sun4i_usb_phy_cfg *cfg; enum usb_dr_mode dr_mode; - struct mutex mutex; + spinlock_t reg_lock; /* guard access to phyctl reg */ struct sun4i_usb_phy { struct phy *phy; void __iomem *pmu; @@ -181,9 +182,10 @@ static void sun4i_usb_phy_write(struct sun4i_usb_phy *phy, u32 addr, u32 data, struct sun4i_usb_phy_data *phy_data = to_sun4i_usb_phy_data(phy); u32 temp, usbc_bit = BIT(phy->index * 2); void __iomem *phyctl = phy_data->base + phy_data->cfg->phyctl_offset; + unsigned long flags; int i; - mutex_lock(&phy_data->mutex); + spin_lock_irqsave(&phy_data->reg_lock, flags); if (phy_data->cfg->type == sun8i_a33_phy || phy_data->cfg->type == sun50i_a64_phy) { @@ -221,7 +223,8 @@ static void sun4i_usb_phy_write(struct sun4i_usb_phy *phy, u32 addr, u32 data, data >>= 1; } - mutex_unlock(&phy_data->mutex); + + spin_unlock_irqrestore(&phy_data->reg_lock, flags); } static void sun4i_usb_phy_passby(struct sun4i_usb_phy *phy, int enable) @@ -615,7 +618,7 @@ static int sun4i_usb_phy_probe(struct platform_device *pdev) if (!data) return -ENOMEM; - mutex_init(&data->mutex); + spin_lock_init(&data->reg_lock); INIT_DELAYED_WORK(&data->detect, sun4i_usb_phy0_id_vbus_det_scan); dev_set_drvdata(dev, data); data->cfg = of_device_get_match_data(dev); |