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author | Chen-Yu Tsai <wens@csie.org> | 2016-09-09 11:58:18 +0800 |
---|---|---|
committer | Ben Hutchings <ben@decadent.org.uk> | 2017-02-23 03:53:59 +0000 |
commit | 17fe3f2631a4d15723d11e0f7e5ee204a6282ee0 (patch) | |
tree | 4c0fbbf86efffe2116882aebf16340ad235c2a41 /drivers/phy | |
parent | 67d7d69d4b23bc9bde53b274d6899ea0532ba0f7 (diff) | |
download | linux-stable-17fe3f2631a4d15723d11e0f7e5ee204a6282ee0.tar.gz linux-stable-17fe3f2631a4d15723d11e0f7e5ee204a6282ee0.tar.bz2 linux-stable-17fe3f2631a4d15723d11e0f7e5ee204a6282ee0.zip |
phy: sun4i-usb: Use spinlock to guard phyctl register access
commit 919ab2524c52e5f801d8873f09145ce822cdd43a upstream.
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>
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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
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 115d8d5190d5..6e46a0055887 100644 --- a/drivers/phy/phy-sun4i-usb.c +++ b/drivers/phy/phy-sun4i-usb.c @@ -32,6 +32,7 @@ #include <linux/platform_device.h> #include <linux/regulator/consumer.h> #include <linux/reset.h> +#include <linux/spinlock.h> #define REG_ISCR 0x00 #define REG_PHYCTL 0x04 @@ -62,7 +63,7 @@ struct sun4i_usb_phy_data { void __iomem *base; - struct mutex mutex; + spinlock_t reg_lock; /* guard access to phyctl reg */ int num_phys; u32 disc_thresh; struct sun4i_usb_phy { @@ -83,9 +84,10 @@ 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); + unsigned long flags; int i; - mutex_lock(&phy_data->mutex); + spin_lock_irqsave(&phy_data->reg_lock, flags); for (i = 0; i < len; i++) { temp = readl(phy_data->base + REG_PHYCTL); @@ -117,7 +119,8 @@ 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) @@ -232,7 +235,7 @@ static int sun4i_usb_phy_probe(struct platform_device *pdev) if (!data) return -ENOMEM; - mutex_init(&data->mutex); + spin_lock_init(&data->reg_lock); if (of_device_is_compatible(np, "allwinner,sun5i-a13-usb-phy")) data->num_phys = 2; |