brcm2708: add linux 4.9 support

Patches from Raspberry Pi repo:
https://github.com/raspberrypi/linux/commits/rpi-4.9.y

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>

1 files changed, 90 insertions, 0 deletions

diff --git a/target/linux/brcm2708/patches-4.9/0107-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch b/target/linux/brcm2708/patches-4.9/0107-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch
new file mode 100644
index 0000000000..7692a92467
--- /dev/null
+++ b/target/linux/brcm2708/patches-4.9/0107-i2c-bcm2835-Fix-hang-for-writing-messages-larger-tha.patch
@@ -0,0 +1,90 @@
+From b302b7c9025334ef6680955a906cee579bf3c85c 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);