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authorChen-Yu Tsai <wens@csie.org>2016-09-09 06:58:18 +0300
committerKishon Vijay Abraham I <kishon@ti.com>2016-09-10 15:13:38 +0300
commit919ab2524c52e5f801d8873f09145ce822cdd43a (patch)
treebd4c5dfb63234437eb363bfe8b7ac0398dfb3bfe /drivers/phy
parent0f74ab59ce8712e7e2bb1e4517033328e626b27c (diff)
downloadlinux-919ab2524c52e5f801d8873f09145ce822cdd43a.tar.xz
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.c11
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);