ARM: sunxi: Add support for using R_UART as console

The A23 only has UART0 muxed with MMC0. Some of the boards we
encountered expose R_UART as a set of pads.

Add support for R_UART so we can have a console while using mmc.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
diff --git a/arch/arm/cpu/armv7/sunxi/clock_sun6i.c b/arch/arm/cpu/armv7/sunxi/clock_sun6i.c
index 8387b93..1eae976 100644
--- a/arch/arm/cpu/armv7/sunxi/clock_sun6i.c
+++ b/arch/arm/cpu/armv7/sunxi/clock_sun6i.c
@@ -13,6 +13,7 @@
 #include <common.h>
 #include <asm/io.h>
 #include <asm/arch/clock.h>
+#include <asm/arch/prcm.h>
 #include <asm/arch/sys_proto.h>
 
 void clock_init_uart(void)
@@ -20,6 +21,7 @@
 	struct sunxi_ccm_reg *const ccm =
 		(struct sunxi_ccm_reg *)SUNXI_CCM_BASE;
 
+#if CONFIG_CONS_INDEX < 5
 	/* uart clock source is apb2 */
 	writel(APB2_CLK_SRC_OSC24M|
 	       APB2_CLK_RATE_N_1|
@@ -35,6 +37,10 @@
 	setbits_le32(&ccm->apb2_reset_cfg,
 		     1 << (APB2_RESET_UART_SHIFT +
 			   CONFIG_CONS_INDEX - 1));
+#else
+	/* enable R_PIO and R_UART clocks, and de-assert resets */
+	prcm_apb0_enable(PRCM_APB0_GATE_PIO | PRCM_APB0_GATE_UART);
+#endif
 
 	/* Dup with clock_init_safe(), drop once sun6i SPL support lands */
 	writel(PLL6_CFG_DEFAULT, &ccm->pll6_cfg);