[U-Boot] [PATCH 3/4] MIPS: mscc: ocelot: add switch reset support

[Gregory CLEMENT <gregory.clement@bootlin.com>]

On some ocelots platform a workaround is needed in order to be able to
reset the switch without resetting the DDR.

Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
---
 board/mscc/ocelot/ocelot.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/board/mscc/ocelot/ocelot.c b/board/mscc/ocelot/ocelot.c
index 0f7a532158..88f59e8044 100644
--- a/board/mscc/ocelot/ocelot.c
+++ b/board/mscc/ocelot/ocelot.c
@@ -18,6 +18,34 @@ enum {
 	BOARD_TYPE_PCB123,
 };
 
+void mscc_switch_reset(bool enter)
+{
+	u32 reg, count = 0;
+
+	/* Nasty workaround to avoid GPIO19 (DDR!) being reset */
+	mscc_gpio_set_alternate(19, 2);
+
+	printf("applying SwC reset\n");
+
+	writel(ICPU_RESET_CORE_RST_PROTECT, BASE_CFG + ICPU_RESET);
+	writel(PERF_SOFT_RST_SOFT_CHIP_RST, BASE_DEVCPU_GCB + PERF_SOFT_RST);
+
+	do {
+		reg = readl(BASE_DEVCPU_GCB + PERF_SOFT_RST);
+		count++;
+	} while (reg & PERF_SOFT_RST_SOFT_CHIP_RST);
+
+	printf("SwC reset done - reg = 0x%08x, count %u\n", reg, count);
+
+	/*
+	 * Reset GPIO19 mode back as regular GPIO, output, high (DDR
+	 * not reset) (Order is important)
+	 */
+	setbits_le32(BASE_DEVCPU_GCB + PERF_GPIO_OE, BIT(19));
+	writel(BIT(19), BASE_DEVCPU_GCB + PERF_GPIO_OUT_SET);
+	mscc_gpio_set_alternate(19, 0);
+}
+
 void board_debug_uart_init(void)
 {
 	/* too early for the pinctrl driver, so configure the UART pins here */
-- 
2.20.1