rockchip: Add support for chromebook_bob

Bob is a 10-inch chromebook produced by Asus. It has two USB 3.0 type-C
ports, 4GB of SDRAM, WiFi and a 1280x800 display. It uses its USB ports
for both power and external display. It includes a Chrome OS EC
(Cortex-M3) to provide access to the keyboard and battery functions.

Support so far includes only:
- UART
- SDRAM
- MMC, SD card
- Cros EC (but not keyboard)

Not included:
- Keyboard
- Display
- Sound
- USB
- TPM

Bob is quite similar to Kevin, the Samsung Chromebook Plus, but support
for this is not provided in this series.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
diff --git a/arch/arm/mach-rockchip/rk3399-board-spl.c b/arch/arm/mach-rockchip/rk3399-board-spl.c
index 5453b2a..906aaf4 100644
--- a/arch/arm/mach-rockchip/rk3399-board-spl.c
+++ b/arch/arm/mach-rockchip/rk3399-board-spl.c
@@ -9,6 +9,7 @@
 #include <dm.h>
 #include <ram.h>
 #include <spl.h>
+#include <spl_gpio.h>
 #include <syscon.h>
 #include <asm/io.h>
 #include <asm/arch/bootrom.h>
@@ -16,6 +17,7 @@
 #include <asm/arch/grf_rk3399.h>
 #include <asm/arch/hardware.h>
 #include <asm/arch/periph.h>
+#include <asm/arch/sys_proto.h>
 #include <dm/pinctrl.h>
 
 void board_return_to_bootrom(void)
@@ -128,7 +130,13 @@
 void board_debug_uart_init(void)
 {
 #define GRF_BASE	0xff770000
+#define GPIO0_BASE	0xff720000
+#define PMUGRF_BASE	0xff320000
 	struct rk3399_grf_regs * const grf = (void *)GRF_BASE;
+#ifdef CONFIG_TARGET_CHROMEBOOK_BOB
+	struct rk3399_pmugrf_regs * const pmugrf = (void *)PMUGRF_BASE;
+	struct rockchip_gpio_regs * const gpio = (void *)GPIO0_BASE;
+#endif
 
 #if defined(CONFIG_DEBUG_UART_BASE) && (CONFIG_DEBUG_UART_BASE == 0xff180000)
 	/* Enable early UART0 on the RK3399 */
@@ -139,6 +147,20 @@
 		     GRF_GPIO2C1_SEL_MASK,
 		     GRF_UART0BT_SOUT << GRF_GPIO2C1_SEL_SHIFT);
 #else
+# ifdef CONFIG_TARGET_CHROMEBOOK_BOB
+	rk_setreg(&grf->io_vsel, 1 << 0);
+
+	/*
+	 * Let's enable these power rails here, we are already running the SPI
+	 * Flash based code.
+	 */
+	spl_gpio_output(gpio, GPIO(BANK_B, 2), 1);  /* PP1500_EN */
+	spl_gpio_set_pull(&pmugrf->gpio0_p, GPIO(BANK_B, 2), GPIO_PULL_NORMAL);
+
+	spl_gpio_output(gpio, GPIO(BANK_B, 4), 1);  /* PP3000_EN */
+	spl_gpio_set_pull(&pmugrf->gpio0_p, GPIO(BANK_B, 4), GPIO_PULL_NORMAL);
+#endif /* CONFIG_TARGET_CHROMEBOOK_BOB */
+
 	/* Enable early UART2 channel C on the RK3399 */
 	rk_clrsetreg(&grf->gpio4c_iomux,
 		     GRF_GPIO4C3_SEL_MASK,
@@ -163,6 +185,22 @@
 
 #define EARLY_UART
 #ifdef EARLY_UART
+# ifdef CONFIG_TARGET_CHROMEBOOK_BOB
+	int sum, i;
+
+	debug_uart_init();
+
+	/*
+	 * Add a delay and ensure that the compiler does not optimise this out.
+	 * This is needed since the power rails tail a while to turn on, and
+	 * we get garbage serial output otherwise.
+	 */
+	sum = 0;
+	for (i = 0; i < 150000; i++)
+		sum += i;
+	gru_dummy_function(sum);
+#endif /* CONFIG_TARGET_CHROMEBOOK_BOB */
+
 	/*
 	 * Debug UART can be used from here if required:
 	 *
@@ -171,7 +209,6 @@
 	 * printhex8(0x1234);
 	 * printascii("string");
 	 */
-	debug_uart_init();
 	printascii("U-Boot SPL board init\n");
 #endif