MIPS: ralink: Put the pci bus into reset state before rebooting the SoC

Some pcie cards have problems after a reboot without this.
Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11446/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/ralink/reset.c

@@ -11,6 +11,7 @@
 #include <linux/pm.h>
 #include <linux/io.h>
 #include <linux/of.h>
+#include <linux/delay.h>
 #include <linux/reset-controller.h>
 
 #include <asm/reboot.h>
@@ -19,6 +20,8 @@
 
 /* Reset Control */
 #define SYSC_REG_RESET_CTRL	0x034
+
+#define RSTCTL_RESET_PCI	BIT(26)
 #define RSTCTL_RESET_SYSTEM	BIT(0)
 
 static int ralink_assert_device(struct reset_controller_dev *rcdev,
@@ -83,6 +86,11 @@ void ralink_rst_init(void)
 
 static void ralink_restart(char *command)
 {
+	if (IS_ENABLED(CONFIG_PCI)) {
+		rt_sysc_m32(0, RSTCTL_RESET_PCI, SYSC_REG_RESET_CTRL);
+		mdelay(50);
+	}
+
 	local_irq_disable();
 	rt_sysc_w32(RSTCTL_RESET_SYSTEM, SYSC_REG_RESET_CTRL);
 	unreachable();