diff options
Diffstat (limited to 'recipes-kernel/linux/linux-raspberrypi/0002-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch')
| -rw-r--r-- | recipes-kernel/linux/linux-raspberrypi/0002-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch | 235 |
1 files changed, 235 insertions, 0 deletions
diff --git a/recipes-kernel/linux/linux-raspberrypi/0002-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch b/recipes-kernel/linux/linux-raspberrypi/0002-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch new file mode 100644 index 0000000..907ed7b --- /dev/null +++ b/recipes-kernel/linux/linux-raspberrypi/0002-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch @@ -0,0 +1,235 @@ +From 2c84355bf200f4d19d7078dee2c63011ad715395 Mon Sep 17 00:00:00 2001 +From: jeanleflambeur <catalin.vasile@gmail.com> +Date: Sun, 1 Feb 2015 12:35:38 +0100 +Subject: [PATCH 2/2] Fix grabbing lock from atomic context in i2c driver +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +(cherry-pick from 558d0bfc8fe80ccdccee7f03e881a80965ec987c) + +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 + +Upstream-Status: Pending + +Signed-off-by: Petter Mabäcker <petter@technux.se> + +Conflicts: + drivers/i2c/busses/i2c-bcm2708.c +--- + drivers/i2c/busses/i2c-bcm2708.c | 88 +++++++++++++++++++++++++++++----------- + 1 file changed, 65 insertions(+), 23 deletions(-) + +diff --git a/drivers/i2c/busses/i2c-bcm2708.c b/drivers/i2c/busses/i2c-bcm2708.c +index 05531db..886672c 100644 +--- a/drivers/i2c/busses/i2c-bcm2708.c ++++ b/drivers/i2c/busses/i2c-bcm2708.c +@@ -67,6 +67,7 @@ + #define BSC_S_TA 0x00000001 + + #define I2C_TIMEOUT_MS 150 ++#define I2C_WAIT_LOOP_COUNT 40 + + #define DRV_NAME "bcm2708_i2c" + +@@ -85,6 +86,7 @@ struct bcm2708_i2c { + void __iomem *base; + int irq; + struct clk *clk; ++ u32 cdiv; + + struct completion done; + +@@ -108,10 +110,10 @@ static void bcm2708_i2c_init_pinmode(int id) + int pin; + u32 *gpio = ioremap(0x20200000, 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 */ + } +@@ -150,16 +152,16 @@ 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; +@@ -176,17 +178,25 @@ 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++; +@@ -196,6 +206,8 @@ 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) +@@ -203,13 +215,15 @@ 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); + +@@ -217,13 +231,16 @@ 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); + +@@ -231,8 +248,19 @@ 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); + } +@@ -265,21 +293,34 @@ static int bcm2708_i2c_master_xfer(struct i2c_adapter *adap, + bi->nmsgs = num; + bi->error = false; + ++ ret = bcm2708_bsc_setup(bi); + spin_unlock_irqrestore(&bi->lock, flags); + + bcm2708_bsc_setup(bi); + +- 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) +@@ -382,6 +423,7 @@ 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); +-- +1.9.1 + |