misc: cec: Fix bug potentially cause system hang

Remove wait_event_interruptible() from interrupt context
Change init_done to be atomic_t and reset as early as possible

Bug 1395893

Change-Id: Ib0cf423a3405293000b0c0d9aa105da5bba22e53
Signed-off-by: Xia Yang <xiay@nvidia.com>
Reviewed-on: http://git-master/r/304631
(cherry picked from commit ef034436a3c8aaf7a9ce5dd9ebaf8dc90dbcce4b)
Signed-off-by: Xia Yang <xiay@nvidia.com>
Reviewed-on: http://git-master/r/346042
Reviewed-on: http://git-master/r/1164141
(cherry picked from commit 76e681f957b27323227c9990679631636084b6ae)
This commit is contained in:
Xia Yang
2013-10-28 17:51:50 -07:00
committed by Prafull Suryawanshi
parent b38ef51b1a
commit ab709208e8
2 changed files with 13 additions and 9 deletions

View File

@@ -47,7 +47,8 @@ int tegra_cec_open(struct inode *inode, struct file *file)
struct tegra_cec, misc_dev); struct tegra_cec, misc_dev);
dev_dbg(cec->dev, "%s\n", __func__); dev_dbg(cec->dev, "%s\n", __func__);
wait_event_interruptible(cec->init_waitq, cec->init_done == 1); wait_event_interruptible(cec->init_waitq,
atomic_read(&cec->init_done) == 1);
file->private_data = cec; file->private_data = cec;
return 0; return 0;
@@ -70,7 +71,8 @@ ssize_t tegra_cec_write(struct file *file, const char __user *buffer,
count = 4; count = 4;
wait_event_interruptible(cec->init_waitq, cec->init_done == 1); wait_event_interruptible(cec->init_waitq,
atomic_read(&cec->init_done) == 1);
if (copy_from_user(&write_buff, buffer, count)) if (copy_from_user(&write_buff, buffer, count))
return -EFAULT; return -EFAULT;
@@ -106,7 +108,8 @@ ssize_t tegra_cec_read(struct file *file, char __user *buffer,
struct tegra_cec *cec = file->private_data; struct tegra_cec *cec = file->private_data;
count = 2; count = 2;
wait_event_interruptible(cec->init_waitq, cec->init_done == 1); wait_event_interruptible(cec->init_waitq,
atomic_read(&cec->init_done) == 1);
if (cec->rx_wake == 0) if (cec->rx_wake == 0)
if (file->f_flags & O_NONBLOCK) if (file->f_flags & O_NONBLOCK)
@@ -128,8 +131,6 @@ static irqreturn_t tegra_cec_irq_handler(int irq, void *data)
struct tegra_cec *cec = dev_get_drvdata(dev); struct tegra_cec *cec = dev_get_drvdata(dev);
unsigned long status; unsigned long status;
wait_event_interruptible(cec->init_waitq, cec->init_done == 1);
status = readl(cec->cec_base + TEGRA_CEC_INT_STAT); status = readl(cec->cec_base + TEGRA_CEC_INT_STAT);
if (!status) if (!status)
@@ -186,8 +187,6 @@ static void tegra_cec_init(struct tegra_cec *cec)
dev_notice(cec->dev, "%s started\n", __func__); dev_notice(cec->dev, "%s started\n", __func__);
cec->init_done = 0;
writel(0x00, cec->cec_base + TEGRA_CEC_HW_CONTROL); writel(0x00, cec->cec_base + TEGRA_CEC_HW_CONTROL);
writel(0x00, cec->cec_base + TEGRA_CEC_INT_MASK); writel(0x00, cec->cec_base + TEGRA_CEC_INT_MASK);
writel(0xffffffff, cec->cec_base + TEGRA_CEC_INT_STAT); writel(0xffffffff, cec->cec_base + TEGRA_CEC_INT_STAT);
@@ -245,7 +244,7 @@ static void tegra_cec_init(struct tegra_cec *cec)
TEGRA_CEC_INT_MASK_RX_REGISTER_OVERRUN), TEGRA_CEC_INT_MASK_RX_REGISTER_OVERRUN),
cec->cec_base + TEGRA_CEC_INT_MASK); cec->cec_base + TEGRA_CEC_INT_MASK);
cec->init_done = 1; atomic_set(&cec->init_done, 1);
wake_up_interruptible(&cec->init_waitq); wake_up_interruptible(&cec->init_waitq);
dev_notice(cec->dev, "%s Done.\n", __func__); dev_notice(cec->dev, "%s Done.\n", __func__);
@@ -302,6 +301,8 @@ static int tegra_cec_probe(struct platform_device *pdev)
goto cec_error; goto cec_error;
} }
atomic_set(&cec->init_done, 0);
cec->clk = clk_get(&pdev->dev, "cec"); cec->clk = clk_get(&pdev->dev, "cec");
if (IS_ERR_OR_NULL(cec->clk)) { if (IS_ERR_OR_NULL(cec->clk)) {
@@ -379,6 +380,8 @@ static int tegra_cec_suspend(struct platform_device *pdev, pm_message_t state)
/* cancel the work queue */ /* cancel the work queue */
cancel_work_sync(&cec->work); cancel_work_sync(&cec->work);
atomic_set(&cec->init_done, 0);
clk_disable(cec->clk); clk_disable(cec->clk);
dev_notice(&pdev->dev, "suspended\n"); dev_notice(&pdev->dev, "suspended\n");

View File

@@ -17,6 +17,7 @@
*/ */
#include <linux/pm.h> #include <linux/pm.h>
#include <asm/atomic.h>
struct tegra_cec { struct tegra_cec {
@@ -31,7 +32,7 @@ struct tegra_cec {
unsigned int rx_wake; unsigned int rx_wake;
unsigned int tx_wake; unsigned int tx_wake;
unsigned short rx_buffer; unsigned short rx_buffer;
unsigned int init_done; atomic_t init_done;
struct work_struct work; struct work_struct work;
}; };
static int tegra_cec_remove(struct platform_device *pdev); static int tegra_cec_remove(struct platform_device *pdev);