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meta-raspberrypi/recipes-kernel/linux/linux-raspberrypi/0002-Fix-grabbing-lock-from-atomic-context-in-i2c-driver.patch
Petter Mabäcker e1c5efc658 linux-raspberrypi: Add 3.14 support 
Add basic support for Linux 3.14, cherry-pick changes from 3.18.y in
order to solve some debugfs warnings and get better support
for i2s for BCM2708.

- 3.14 lacks BCM2709 support and will not by default be able to use for
raspberry pi 2.

Below warnings still exists they are harmless and exists due to that
snd_soc_pcm512x is triggered to be loaded twice. The problem is solved
after device tree support for the driver was introduced in 3.18.y and no
easy solution exists to solve this problem on older kernel versions (see
https://github.com/raspberrypi/linux/issues/662 for more info).

   pcm512x 1-004c: Failed to reset device: -5
   pcm512x: probe of 1-004c failed with error

Remove sl030raspberrypii2ckernel.patch since it will not apply anymore
and its content seems to be obsolite after cherry-picking
'558d0bf Fix grabbing lock from atomic context in i2c driver'.

[Support #57]

Signed-off-by: Petter Mabäcker <petter@technux.se>
Signed-off-by: Andrei Gherzan <andrei@gherzan.ro>
2015-05-18 00:48:49 +02:00

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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
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