[PATCH v4 3/5] rockchip: rk3528: Implement read_brom_bootsource_id()

[Jonas Karlman]

The bootsource ids reported by BootROM of RK3528 for e.g. USB differs
compared to prior SoCs:

- Booting from USB report a new bootsource id 0x81.

Add a RK3528 specific read_brom_bootsource_id() function to help decode
this new bootsource id value to help support booting from USB on RK3528.

Signed-off-by: Jonas Karlman <jonas at kwiboo.se>
---
v4: No change
v3: New patch to map USB bootsource id on RK3528
---
 arch/arm/mach-rockchip/rk3528/rk3528.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch/arm/mach-rockchip/rk3528/rk3528.c b/arch/arm/mach-rockchip/rk3528/rk3528.c
index f9bfc445b857..57ead0006f1f 100644
--- a/arch/arm/mach-rockchip/rk3528/rk3528.c
+++ b/arch/arm/mach-rockchip/rk3528/rk3528.c
@@ -49,6 +49,21 @@ void board_debug_uart_init(void)
 {
 }
 
+u32 read_brom_bootsource_id(void)
+{
+	u32 bootsource_id = readl(BROM_BOOTSOURCE_ID_ADDR);
+
+	/* Re-map the raw value read from reg to an existing BROM_BOOTSOURCE
+	 * enum value to avoid having to create a larger boot_devices table.
+	 */
+	if (bootsource_id == 0x81)
+		return BROM_BOOTSOURCE_USB;
+	else if (bootsource_id > BROM_LAST_BOOTSOURCE)
+		log_debug("Unknown bootsource %x\n", bootsource_id);
+
+	return bootsource_id;
+}
+
 int arch_cpu_init(void)
 {
 	u32 val;
-- 
2.51.0