rockchip: rk3188: add support for usb-uart functionality

Rockchip socs can route the debug uart pins through the d+ and d- pins
of one specific usbphy per soc. Add a config option and implement the
setting on the rk3188.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>
[Fixed up to mark grf as maybe unused:]
Signed-off-by: Philipp Tomsich <philipp.tomsich@theobroma-systems.com>

arch/arm/include/asm/arch-rockchip/grf_rk3188.h

@@ -205,4 +205,46 @@ enum {
 	ATO_AE_SHIFT		= 0,
 	ATO_AE_MASK		= 1,
 };
+
+/* GRF_UOC_CON0 */
+enum {
+	SIDDQ_SHIFT		= 13,
+	SIDDQ_MASK		= 1 << SIDDQ_SHIFT,
+
+	BYPASSSEL_SHIFT		= 9,
+	BYPASSSEL_MASK		= 1 << BYPASSSEL_SHIFT,
+
+	BYPASSDMEN_SHIFT	= 8,
+	BYPASSDMEN_MASK		= 1 << BYPASSDMEN_SHIFT,
+
+	UOC_DISABLE_SHIFT	= 4,
+	UOC_DISABLE_MASK	= 1 << UOC_DISABLE_SHIFT,
+
+	COMMON_ON_N_SHIFT	= 0,
+	COMMON_ON_N_MASK	= 1 << COMMON_ON_N_SHIFT,
+};
+
+/* GRF_UOC_CON2 */
+enum {
+	SOFT_CON_SEL_SHIFT	= 2,
+	SOFT_CON_SEL_MASK	= 1 << SOFT_CON_SEL_SHIFT,
+};
+
+/* GRF_UOC0_CON3 */
+enum {
+	TERMSEL_FULLSPEED_SHIFT	= 5,
+	TERMSEL_FULLSPEED_MASK	= 1 << TERMSEL_FULLSPEED_SHIFT,
+
+	XCVRSELECT_SHIFT	= 3,
+	XCVRSELECT_FSTRANSC	= 1,
+	XCVRSELECT_MASK		= 3 << XCVRSELECT_SHIFT,
+
+	OPMODE_SHIFT		= 1,
+	OPMODE_NODRIVING	= 1,
+	OPMODE_MASK		= 3 << OPMODE_SHIFT,
+
+	SUSPENDN_SHIFT		= 0,
+	SUSPENDN_MASK		= 1 << SUSPENDN_SHIFT,
+};
+
 #endif

arch/arm/mach-rockchip/Kconfig

@@ -156,6 +156,14 @@ config ROCKCHIP_RV1108
 	  The Rockchip RV1108 is a ARM-based SoC with a single-core Cortex-A7
 	  and a DSP.
 
+config ROCKCHIP_USB_UART
+	bool "Route uart output to usb pins"
+	help
+	  Rockchip SoCs have the ability to route the signals of the debug
+	  uart through the d+ and d- pins of a specific usb phy to enable
+	  some form of closed-case debugging. With this option supported
+	  SoCs will enable this routing as a debug measure.
+
 config SPL_ROCKCHIP_BACK_TO_BROM
 	bool "SPL returns to bootrom"
 	default y if ROCKCHIP_RK3036

arch/arm/mach-rockchip/rk3188-board-spl.c

@@ -16,6 +16,7 @@
 #include <asm/io.h>
 #include <asm/arch/bootrom.h>
 #include <asm/arch/clock.h>
+#include <asm/arch/grf_rk3188.h>
 #include <asm/arch/hardware.h>
 #include <asm/arch/periph.h>
 #include <asm/arch/pmu_rk3188.h>
@@ -92,18 +93,17 @@ static int setup_arm_clock(void)
 	return ret;
 }
 
+#define GRF_BASE	0x20008000
+
 void board_init_f(ulong dummy)
 {
+	__maybe_unused struct rk3188_grf * const grf = (void *)GRF_BASE;
 	struct udevice *pinctrl, *dev;
 	int ret;
 
 	/* Example code showing how to enable the debug UART on RK3188 */
 #ifdef EARLY_UART
-#include <asm/arch/grf_rk3188.h>
 	/* Enable early UART on the RK3188 */
-#define GRF_BASE	0x20008000
-	struct rk3188_grf * const grf = (void *)GRF_BASE;
-
 	rk_clrsetreg(&grf->gpio1b_iomux,
 		     GPIO1B1_MASK << GPIO1B1_SHIFT |
 		     GPIO1B0_MASK << GPIO1B0_SHIFT,
@@ -124,6 +124,25 @@ void board_init_f(ulong dummy)
 	printch('\n');
 #endif
 
+#ifdef CONFIG_ROCKCHIP_USB_UART
+	rk_clrsetreg(&grf->uoc0_con[0],
+		     SIDDQ_MASK | UOC_DISABLE_MASK | COMMON_ON_N_MASK,
+		     1 << SIDDQ_SHIFT | 1 << UOC_DISABLE_SHIFT |
+		     1 << COMMON_ON_N_SHIFT);
+	rk_clrsetreg(&grf->uoc0_con[2],
+		     SOFT_CON_SEL_MASK, 1 << SOFT_CON_SEL_SHIFT);
+	rk_clrsetreg(&grf->uoc0_con[3],
+		     OPMODE_MASK | XCVRSELECT_MASK |
+		     TERMSEL_FULLSPEED_MASK | SUSPENDN_MASK,
+		     OPMODE_NODRIVING << OPMODE_SHIFT |
+		     XCVRSELECT_FSTRANSC << XCVRSELECT_SHIFT |
+		     1 << TERMSEL_FULLSPEED_SHIFT |
+		     1 << SUSPENDN_SHIFT);
+	rk_clrsetreg(&grf->uoc0_con[0],
+		     BYPASSSEL_MASK | BYPASSDMEN_MASK,
+		     1 << BYPASSSEL_SHIFT | 1 << BYPASSDMEN_SHIFT);
+#endif
+
 	ret = spl_early_init();
 	if (ret) {
 		debug("spl_early_init() failed: %d\n", ret);