ar71xx: Add kernel 4.9 support

This add support for kernel 4.9 to the ar71xx target.
It was compile tested with the generic, NAND and mikrotik subtarget.
Multiple members of the community tested it on their boards and did not
report any major problem so far.

Especially the NAND part received some changes to adapt to the new
kernel APIs. The serial driver hack used for the Arduino Yun was not
ported because the kernel changed there a lot.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>

1 files changed, 61 insertions, 0 deletions

diff --git a/target/linux/ar71xx/patches-4.9/521-MIPS-ath79-enable-UART-for-early_serial.patch b/target/linux/ar71xx/patches-4.9/521-MIPS-ath79-enable-UART-for-early_serial.patch
new file mode 100644
index 0000000000..e546ff26fe
--- /dev/null
+++ b/target/linux/ar71xx/patches-4.9/521-MIPS-ath79-enable-UART-for-early_serial.patch
@@ -0,0 +1,61 @@
+--- a/arch/mips/ath79/early_printk.c
++++ b/arch/mips/ath79/early_printk.c
+@@ -58,6 +58,46 @@ static void prom_putchar_dummy(unsigned
+ 	/* nothing to do */
+ }
+ 
++static void prom_enable_uart(u32 id)
++{
++	void __iomem *gpio_base;
++	u32 uart_en;
++	u32 t;
++
++	switch (id) {
++	case REV_ID_MAJOR_AR71XX:
++		uart_en = AR71XX_GPIO_FUNC_UART_EN;
++		break;
++
++	case REV_ID_MAJOR_AR7240:
++	case REV_ID_MAJOR_AR7241:
++	case REV_ID_MAJOR_AR7242:
++		uart_en = AR724X_GPIO_FUNC_UART_EN;
++		break;
++
++	case REV_ID_MAJOR_AR913X:
++		uart_en = AR913X_GPIO_FUNC_UART_EN;
++		break;
++
++	case REV_ID_MAJOR_AR9330:
++	case REV_ID_MAJOR_AR9331:
++		uart_en = AR933X_GPIO_FUNC_UART_EN;
++		break;
++
++	case REV_ID_MAJOR_AR9341:
++	case REV_ID_MAJOR_AR9342:
++	case REV_ID_MAJOR_AR9344:
++		/* TODO */
++	default:
++		return;
++	}
++
++	gpio_base = (void __iomem *)(KSEG1ADDR(AR71XX_GPIO_BASE));
++	t = __raw_readl(gpio_base + AR71XX_GPIO_REG_FUNC);
++	t |= uart_en;
++	__raw_writel(t, gpio_base + AR71XX_GPIO_REG_FUNC);
++}
++
+ static void prom_putchar_init(void)
+ {
+ 	void __iomem *base;
+@@ -88,8 +128,10 @@ static void prom_putchar_init(void)
+ 
+ 	default:
+ 		_prom_putchar = prom_putchar_dummy;
+-		break;
++		return;
+ 	}
++
++	prom_enable_uart(id);
+ }
+ 
+ void prom_putchar(unsigned char ch)