diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch | 90 |
1 files changed, 0 insertions, 90 deletions
diff --git a/target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch b/target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch deleted file mode 100644 index 899c75e0db..0000000000 --- a/target/linux/brcm2708/patches-4.9/950-0106-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch +++ /dev/null @@ -1,90 +0,0 @@ -From 89b466914a0d49f08d00be25556ba22497b9a284 Mon Sep 17 00:00:00 2001 -From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org> -Date: Sat, 17 Sep 2016 15:07:10 +0200 -Subject: [PATCH] i2c: bcm2835: Fix hang for writing messages larger than 16 - bytes -MIME-Version: 1.0 -Content-Type: text/plain; charset=UTF-8 -Content-Transfer-Encoding: 8bit - -Writing messages larger than the FIFO size results in a hang, rendering -the machine unusable. This is because the RXD status flag is set on the -first interrupt which results in bcm2835_drain_rxfifo() stealing bytes -from the buffer. The controller continues to trigger interrupts waiting -for the missing bytes, but bcm2835_fill_txfifo() has none to give. -In this situation wait_for_completion_timeout() apparently is unable to -stop the madness. - -The BCM2835 ARM Peripherals datasheet has this to say about the flags: - TXD: is set when the FIFO has space for at least one byte of data. - RXD: is set when the FIFO contains at least one byte of data. - TXW: is set during a write transfer and the FIFO is less than full. - RXR: is set during a read transfer and the FIFO is or more full. - -Implementing the logic from the downstream i2c-bcm2708 driver solved -the hang problem. - -Signed-off-by: Noralf Trønnes <noralf@tronnes.org> -Reviewed-by: Eric Anholt <eric@anholt.net> -Reviewed-by: Martin Sperl <kernel@martin.sperl.org> ---- - drivers/i2c/busses/i2c-bcm2835.c | 22 ++++++++++++++-------- - 1 file changed, 14 insertions(+), 8 deletions(-) - ---- a/drivers/i2c/busses/i2c-bcm2835.c -+++ b/drivers/i2c/busses/i2c-bcm2835.c -@@ -64,6 +64,7 @@ struct bcm2835_i2c_dev { - int irq; - struct i2c_adapter adapter; - struct completion completion; -+ struct i2c_msg *curr_msg; - u32 msg_err; - u8 *msg_buf; - size_t msg_buf_remaining; -@@ -126,14 +127,13 @@ static irqreturn_t bcm2835_i2c_isr(int t - return IRQ_HANDLED; - } - -- if (val & BCM2835_I2C_S_RXD) { -- bcm2835_drain_rxfifo(i2c_dev); -- if (!(val & BCM2835_I2C_S_DONE)) -- return IRQ_HANDLED; -- } -- - if (val & BCM2835_I2C_S_DONE) { -- if (i2c_dev->msg_buf_remaining) -+ if (i2c_dev->curr_msg->flags & I2C_M_RD) { -+ bcm2835_drain_rxfifo(i2c_dev); -+ val = bcm2835_i2c_readl(i2c_dev, BCM2835_I2C_S); -+ } -+ -+ if ((val & BCM2835_I2C_S_RXD) || i2c_dev->msg_buf_remaining) - i2c_dev->msg_err = BCM2835_I2C_S_LEN; - else - i2c_dev->msg_err = 0; -@@ -141,11 +141,16 @@ static irqreturn_t bcm2835_i2c_isr(int t - return IRQ_HANDLED; - } - -- if (val & BCM2835_I2C_S_TXD) { -+ if (val & BCM2835_I2C_S_TXW) { - bcm2835_fill_txfifo(i2c_dev); - return IRQ_HANDLED; - } - -+ if (val & BCM2835_I2C_S_RXR) { -+ bcm2835_drain_rxfifo(i2c_dev); -+ return IRQ_HANDLED; -+ } -+ - return IRQ_NONE; - } - -@@ -155,6 +160,7 @@ static int bcm2835_i2c_xfer_msg(struct b - u32 c; - unsigned long time_left; - -+ i2c_dev->curr_msg = msg; - i2c_dev->msg_buf = msg->buf; - i2c_dev->msg_buf_remaining = msg->len; - reinit_completion(&i2c_dev->completion); |