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Diffstat (limited to 'target/linux/brcm2708/patches-3.18/0112-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch')
-rwxr-xr-xtarget/linux/brcm2708/patches-3.18/0112-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch224
1 files changed, 224 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-3.18/0112-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch b/target/linux/brcm2708/patches-3.18/0112-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch
new file mode 100755
index 0000000000..ecd13fad64
--- /dev/null
+++ b/target/linux/brcm2708/patches-3.18/0112-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch
@@ -0,0 +1,224 @@
+From 58ee33ad32d4a00735252718f8bac3f7592af6e7 Mon Sep 17 00:00:00 2001
+From: jeanleflambeur <catalin.vasile@gmail.com>
+Date: Sun, 1 Feb 2015 12:35:38 +0100
+Subject: [PATCH 112/114] Fix grabbing lock from atomic context in i2c driver
+
+2 main changes:
+- check for timeouts in the bcm2708_bsc_setup function as indicated by this comment:
+ /* poll for transfer start bit (should only take 1-20 polls) */
+ This implies that the setup function can now fail so account for this everywhere it's called
+- Removed the clk_get_rate call from inside the setup function as it locks a mutex and that's not ok since we call it from under a spin lock.
+
+removed dead code and update comment
+
+fixed typo in comment
+---
+ drivers/i2c/busses/i2c-bcm2708.c | 90 +++++++++++++++++++++++++++++-----------
+ 1 file changed, 65 insertions(+), 25 deletions(-)
+
+diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c
+index fda59ba..81e9374 100644
+--- a/drivers/i2c/busses/i2c-bcm2708.c
++++ b/drivers/i2c/busses/i2c-bcm2708.c
+@@ -68,6 +68,7 @@
+ #define BSC_S_TA 0x00000001
+
+ #define I2C_TIMEOUT_MS 150
++#define I2C_WAIT_LOOP_COUNT 40
+
+ #define DRV_NAME "bcm2708_i2c"
+
+@@ -86,6 +87,7 @@ struct bcm2708_i2c {
+ void __iomem *base;
+ int irq;
+ struct clk *clk;
++ u32 cdiv;
+
+ struct completion done;
+
+@@ -109,10 +111,10 @@ static void bcm2708_i2c_init_pinmode(int id)
+ int pin;
+ u32 *gpio = ioremap(GPIO_BASE, SZ_16K);
+
+- BUG_ON(id != 0 && id != 1);
++ BUG_ON(id != 0 && id != 1);
+ /* BSC0 is on GPIO 0 & 1, BSC1 is on GPIO 2 & 3 */
+ for (pin = id*2+0; pin <= id*2+1; pin++) {
+-printk("bcm2708_i2c_init_pinmode(%d,%d)\n", id, pin);
++ printk("bcm2708_i2c_init_pinmode(%d,%d)\n", id, pin);
+ INP_GPIO(pin); /* set mode to GPIO input first */
+ SET_GPIO_ALT(pin, 0); /* set mode to ALT 0 */
+ }
+@@ -151,16 +153,16 @@ static inline void bcm2708_bsc_fifo_fill(struct bcm2708_i2c *bi)
+ bcm2708_wr(bi, BSC_FIFO, bi->msg->buf[bi->pos++]);
+ }
+
+-static inline void bcm2708_bsc_setup(struct bcm2708_i2c *bi)
++static inline int bcm2708_bsc_setup(struct bcm2708_i2c *bi)
+ {
+- unsigned long bus_hz;
+ u32 cdiv, s;
+ u32 c = BSC_C_I2CEN | BSC_C_INTD | BSC_C_ST | BSC_C_CLEAR_1;
++ int wait_loops = I2C_WAIT_LOOP_COUNT;
+
+- bus_hz = clk_get_rate(bi->clk);
+- cdiv = bus_hz / baudrate;
+- if (cdiv > 0xffff)
+- cdiv = 0xffff;
++ /* Can't call clk_get_rate as it locks a mutex and here we are spinlocked.
++ * Use the value that we cached in the probe.
++ */
++ cdiv = bi->cdiv;
+
+ if (bi->msg->flags & I2C_M_RD)
+ c |= BSC_C_INTR | BSC_C_READ;
+@@ -177,17 +179,25 @@ static inline void bcm2708_bsc_setup(struct bcm2708_i2c *bi)
+ - Both messages to same slave address
+ - Write message can fit inside FIFO (16 bytes or less) */
+ if ( (bi->nmsgs > 1) &&
+- !(bi->msg[0].flags & I2C_M_RD) && (bi->msg[1].flags & I2C_M_RD) &&
+- (bi->msg[0].addr == bi->msg[1].addr) && (bi->msg[0].len <= 16)) {
++ !(bi->msg[0].flags & I2C_M_RD) && (bi->msg[1].flags & I2C_M_RD) &&
++ (bi->msg[0].addr == bi->msg[1].addr) && (bi->msg[0].len <= 16)) {
+ /* Fill FIFO with entire write message (16 byte FIFO) */
+- while (bi->pos < bi->msg->len)
++ while (bi->pos < bi->msg->len) {
+ bcm2708_wr(bi, BSC_FIFO, bi->msg->buf[bi->pos++]);
++ }
+ /* Start write transfer (no interrupts, don't clear FIFO) */
+ bcm2708_wr(bi, BSC_C, BSC_C_I2CEN | BSC_C_ST);
++
+ /* poll for transfer start bit (should only take 1-20 polls) */
+ do {
+ s = bcm2708_rd(bi, BSC_S);
+- } while (!(s & (BSC_S_TA | BSC_S_ERR | BSC_S_CLKT | BSC_S_DONE)));
++ } while (!(s & (BSC_S_TA | BSC_S_ERR | BSC_S_CLKT | BSC_S_DONE)) && --wait_loops >= 0);
++
++ /* did we time out or some error occured? */
++ if (wait_loops < 0 || (s & (BSC_S_ERR | BSC_S_CLKT))) {
++ return -1;
++ }
++
+ /* Send next read message before the write transfer finishes. */
+ bi->nmsgs--;
+ bi->msg++;
+@@ -197,6 +207,8 @@ static inline void bcm2708_bsc_setup(struct bcm2708_i2c *bi)
+ }
+ }
+ bcm2708_wr(bi, BSC_C, c);
++
++ return 0;
+ }
+
+ static irqreturn_t bcm2708_i2c_interrupt(int irq, void *dev_id)
+@@ -204,13 +216,15 @@ static irqreturn_t bcm2708_i2c_interrupt(int irq, void *dev_id)
+ struct bcm2708_i2c *bi = dev_id;
+ bool handled = true;
+ u32 s;
++ int ret;
+
+ spin_lock(&bi->lock);
+
+ /* we may see camera interrupts on the "other" I2C channel
+- Just return if we've not sent anything */
+- if (!bi->nmsgs || !bi->msg )
++ Just return if we've not sent anything */
++ if (!bi->nmsgs || !bi->msg) {
+ goto early_exit;
++ }
+
+ s = bcm2708_rd(bi, BSC_S);
+
+@@ -218,13 +232,16 @@ static irqreturn_t bcm2708_i2c_interrupt(int irq, void *dev_id)
+ bcm2708_bsc_reset(bi);
+ bi->error = true;
+
++ bi->msg = 0; /* to inform the that all work is done */
++ bi->nmsgs = 0;
+ /* wake up our bh */
+ complete(&bi->done);
+ } else if (s & BSC_S_DONE) {
+ bi->nmsgs--;
+
+- if (bi->msg->flags & I2C_M_RD)
++ if (bi->msg->flags & I2C_M_RD) {
+ bcm2708_bsc_fifo_drain(bi);
++ }
+
+ bcm2708_bsc_reset(bi);
+
+@@ -232,8 +249,19 @@ static irqreturn_t bcm2708_i2c_interrupt(int irq, void *dev_id)
+ /* advance to next message */
+ bi->msg++;
+ bi->pos = 0;
+- bcm2708_bsc_setup(bi);
++ ret = bcm2708_bsc_setup(bi);
++ if (ret < 0) {
++ bcm2708_bsc_reset(bi);
++ bi->error = true;
++ bi->msg = 0; /* to inform the that all work is done */
++ bi->nmsgs = 0;
++ /* wake up our bh */
++ complete(&bi->done);
++ goto early_exit;
++ }
+ } else {
++ bi->msg = 0; /* to inform the that all work is done */
++ bi->nmsgs = 0;
+ /* wake up our bh */
+ complete(&bi->done);
+ }
+@@ -266,22 +294,33 @@ static int bcm2708_i2c_master_xfer(struct i2c_adapter *adap,
+ bi->nmsgs = num;
+ bi->error = false;
+
+- bcm2708_bsc_setup(bi);
++ ret = bcm2708_bsc_setup(bi);
+
+- /* unlockig _after_ the setup to avoid races with the interrupt routine */
+ spin_unlock_irqrestore(&bi->lock, flags);
+
+- ret = wait_for_completion_timeout(&bi->done,
+- msecs_to_jiffies(I2C_TIMEOUT_MS));
++ /* check the result of the setup */
++ if (ret < 0)
++ {
++ dev_err(&adap->dev, "transfer setup timed out\n");
++ goto error_timeout;
++ }
++
++ ret = wait_for_completion_timeout(&bi->done, msecs_to_jiffies(I2C_TIMEOUT_MS));
+ if (ret == 0) {
+ dev_err(&adap->dev, "transfer timed out\n");
+- spin_lock_irqsave(&bi->lock, flags);
+- bcm2708_bsc_reset(bi);
+- spin_unlock_irqrestore(&bi->lock, flags);
+- return -ETIMEDOUT;
++ goto error_timeout;
+ }
+
+- return bi->error ? -EIO : num;
++ ret = bi->error ? -EIO : num;
++ return ret;
++
++error_timeout:
++ spin_lock_irqsave(&bi->lock, flags);
++ bcm2708_bsc_reset(bi);
++ bi->msg = 0; /* to inform the interrupt handler that there's nothing else to be done */
++ bi->nmsgs = 0;
++ spin_unlock_irqrestore(&bi->lock, flags);
++ return -ETIMEDOUT;
+ }
+
+ static u32 bcm2708_i2c_functionality(struct i2c_adapter *adap)
+@@ -406,6 +445,7 @@ static int bcm2708_i2c_probe(struct platform_device *pdev)
+ cdiv = 0xffff;
+ baudrate = bus_hz / cdiv;
+ }
++ bi->cdiv = cdiv;
+
+ dev_info(&pdev->dev, "BSC%d Controller at 0x%08lx (irq %d) (baudrate %d)\n",
+ pdev->id, (unsigned long)regs->start, irq, baudrate);
+--
+1.8.3.2
+
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