mirror of https://github.com/hak5/openwrt.git
220 lines
6.7 KiB
Diff
220 lines
6.7 KiB
Diff
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(-)
|
|
|
|
--- 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
|
|
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
|
|
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(str
|
|
- 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(str
|
|
}
|
|
}
|
|
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
|
|
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
|
|
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
|
|
/* 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(struc
|
|
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 plat
|
|
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);
|