feat(imx8m): detect console base address during runtime

Provide a helper to detect the enabled UART device during runtime. This
lower the integration effort and make it more straight forward for
'simple' use-cases with a single UART enabled. If multiple UARTs are
enabled the first enabled is returned.

The auto-detection is enabled by setting IMX_BOOT_UART_BASE=0 to keep
the backward compatibility. For more advanced use-cases (multiple UARTs
are enabled) the user still has to provide the correct base address.

Signed-off-by: Marco Felsch <m.felsch@pengutronix.de>
Change-Id: I300a167e1a10f9aa991c8d1c3efe2c6b23f56c47
diff --git a/plat/imx/imx8m/imx8m_ccm.c b/plat/imx/imx8m/imx8m_ccm.c
new file mode 100644
index 0000000..10a00c9
--- /dev/null
+++ b/plat/imx/imx8m/imx8m_ccm.c
@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2023, Pengutronix. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <lib/mmio.h>
+#include <platform_def.h>
+
+#define UCR1    		0x80
+#define UCR1_UARTEN		BIT(0)
+#define DOMAIN0_RUNNING(d)	(((d) & 0x3) != 0)
+
+static struct imx_uart {
+	unsigned int ccm_reg;
+	unsigned int uart_base;
+} imx8m_uart_info[] = {
+	{	/* UART 1 */
+		.ccm_reg = 0x4490,
+		.uart_base = 0x30860000,
+	}, {	/* UART 2 */
+		.ccm_reg = 0x44a0,
+		.uart_base = 0x30890000,
+	}, {	/* UART 3 */
+		.ccm_reg = 0x44b0,
+		.uart_base = 0x30880000,
+	}, {	/* UART 4 */
+		.ccm_reg = 0x44c0,
+		.uart_base = 0x30a60000,
+	}
+};
+
+unsigned int imx8m_uart_get_base(void)
+{
+	unsigned int i;
+
+	for (i = 0; i < ARRAY_SIZE(imx8m_uart_info); i++) {
+		uint32_t val;
+
+		/*
+		 * At least check that the clock-gate is ungated before we
+		 * access the UART register.
+		 */
+		val = mmio_read_32(IMX_CCM_BASE + imx8m_uart_info[i].ccm_reg);
+		if (DOMAIN0_RUNNING(val)) {
+			val = mmio_read_32(imx8m_uart_info[i].uart_base + UCR1);
+			if (val & UCR1_UARTEN) {
+				return imx8m_uart_info[i].uart_base;
+			}
+		}
+	}
+
+	/*
+	 * We should return an error and inform the user but we can't do it
+	 * this early.
+	 */
+	return 0;
+}
diff --git a/plat/imx/imx8m/imx8mm/imx8mm_bl31_setup.c b/plat/imx/imx8m/imx8mm/imx8mm_bl31_setup.c
index 67bfd36..8e66361 100644
--- a/plat/imx/imx8m/imx8mm/imx8mm_bl31_setup.c
+++ b/plat/imx/imx8m/imx8mm/imx8mm_bl31_setup.c
@@ -27,6 +27,7 @@
 #include <imx_uart.h>
 #include <imx_rdc.h>
 #include <imx8m_caam.h>
+#include <imx8m_ccm.h>
 #include <imx8m_csu.h>
 #include <plat_imx8.h>
 
@@ -130,6 +131,7 @@
 void bl31_early_platform_setup2(u_register_t arg0, u_register_t arg1,
 		u_register_t arg2, u_register_t arg3)
 {
+	unsigned int console_base = 0U;
 	static console_t console;
 	int i;
 
@@ -144,7 +146,14 @@
 
 	imx_csu_init(csu_cfg);
 
-	console_imx_uart_register(IMX_BOOT_UART_BASE, IMX_BOOT_UART_CLK_IN_HZ,
+#if IMX_BOOT_UART_BASE
+	console_base = IMX_BOOT_UART_BASE;
+#endif
+	if (console_base == 0U) {
+		console_base = imx8m_uart_get_base();
+	}
+
+	console_imx_uart_register(console_base, IMX_BOOT_UART_CLK_IN_HZ,
 		IMX_CONSOLE_BAUDRATE, &console);
 	/* This console is only used for boot stage */
 	console_set_scope(&console, CONSOLE_FLAG_BOOT);
diff --git a/plat/imx/imx8m/imx8mm/platform.mk b/plat/imx/imx8m/imx8mm/platform.mk
index 24582f8..2462517 100644
--- a/plat/imx/imx8m/imx8mm/platform.mk
+++ b/plat/imx/imx8m/imx8mm/platform.mk
@@ -37,6 +37,7 @@
 				plat/imx/imx8m/imx_rdc.c			\
 				plat/imx/imx8m/imx8m_csu.c			\
 				plat/imx/imx8m/imx8m_caam.c			\
+				plat/imx/imx8m/imx8m_ccm.c			\
 				plat/imx/imx8m/imx8m_psci_common.c		\
 				plat/imx/imx8m/imx8mm/imx8mm_bl31_setup.c	\
 				plat/imx/imx8m/imx8mm/imx8mm_psci.c		\
diff --git a/plat/imx/imx8m/imx8mn/imx8mn_bl31_setup.c b/plat/imx/imx8m/imx8mn/imx8mn_bl31_setup.c
index eff198d..aeb1cbf 100644
--- a/plat/imx/imx8m/imx8mn/imx8mn_bl31_setup.c
+++ b/plat/imx/imx8m/imx8mn/imx8mn_bl31_setup.c
@@ -25,6 +25,7 @@
 #include <imx_uart.h>
 #include <imx_rdc.h>
 #include <imx8m_caam.h>
+#include <imx8m_ccm.h>
 #include <imx8m_csu.h>
 #include <platform_def.h>
 #include <plat_imx8.h>
@@ -121,6 +122,7 @@
 void bl31_early_platform_setup2(u_register_t arg0, u_register_t arg1,
 		u_register_t arg2, u_register_t arg3)
 {
+	unsigned int console_base = 0U;
 	static console_t console;
 	unsigned int val;
 	int i;
@@ -141,7 +143,14 @@
 	val = mmio_read_32(IMX_IOMUX_GPR_BASE + 0x2c);
 	mmio_write_32(IMX_IOMUX_GPR_BASE + 0x2c, val | 0x3DFF0000);
 
-	console_imx_uart_register(IMX_BOOT_UART_BASE, IMX_BOOT_UART_CLK_IN_HZ,
+#if IMX_BOOT_UART_BASE
+	console_base = IMX_BOOT_UART_BASE;
+#endif
+	if (console_base == 0U) {
+		console_base = imx8m_uart_get_base();
+	}
+
+	console_imx_uart_register(console_base, IMX_BOOT_UART_CLK_IN_HZ,
 		IMX_CONSOLE_BAUDRATE, &console);
 	/* This console is only used for boot stage */
 	console_set_scope(&console, CONSOLE_FLAG_BOOT);
diff --git a/plat/imx/imx8m/imx8mn/platform.mk b/plat/imx/imx8m/imx8mn/platform.mk
index 1c0ad4f..4651610 100644
--- a/plat/imx/imx8m/imx8mn/platform.mk
+++ b/plat/imx/imx8m/imx8mn/platform.mk
@@ -31,6 +31,7 @@
 				plat/imx/imx8m/imx_aipstz.c			\
 				plat/imx/imx8m/imx_rdc.c			\
 				plat/imx/imx8m/imx8m_caam.c			\
+				plat/imx/imx8m/imx8m_ccm.c			\
 				plat/imx/imx8m/imx8m_csu.c			\
 				plat/imx/imx8m/imx8m_psci_common.c		\
 				plat/imx/imx8m/imx8mn/imx8mn_bl31_setup.c	\
diff --git a/plat/imx/imx8m/imx8mp/imx8mp_bl31_setup.c b/plat/imx/imx8m/imx8mp/imx8mp_bl31_setup.c
index 4c31fa2..e25668b 100644
--- a/plat/imx/imx8m/imx8mp/imx8mp_bl31_setup.c
+++ b/plat/imx/imx8m/imx8mp/imx8mp_bl31_setup.c
@@ -25,6 +25,7 @@
 #include <imx_uart.h>
 #include <imx_rdc.h>
 #include <imx8m_caam.h>
+#include <imx8m_ccm.h>
 #include <imx8m_csu.h>
 #include <platform_def.h>
 #include <plat_imx8.h>
@@ -117,6 +118,7 @@
 void bl31_early_platform_setup2(u_register_t arg0, u_register_t arg1,
 		u_register_t arg2, u_register_t arg3)
 {
+	unsigned int console_base = 0U;
 	static console_t console;
 	unsigned int val;
 	unsigned int i;
@@ -137,7 +139,14 @@
 	val = mmio_read_32(IMX_IOMUX_GPR_BASE + 0x2c);
 	mmio_write_32(IMX_IOMUX_GPR_BASE + 0x2c, val | 0x3DFF0000);
 
-	console_imx_uart_register(IMX_BOOT_UART_BASE, IMX_BOOT_UART_CLK_IN_HZ,
+#if IMX_BOOT_UART_BASE
+	console_base = IMX_BOOT_UART_BASE;
+#endif
+	if (console_base == 0U) {
+		console_base = imx8m_uart_get_base();
+	}
+
+	console_imx_uart_register(console_base, IMX_BOOT_UART_CLK_IN_HZ,
 		IMX_CONSOLE_BAUDRATE, &console);
 	/* This console is only used for boot stage */
 	console_set_scope(&console, CONSOLE_FLAG_BOOT);
diff --git a/plat/imx/imx8m/imx8mp/platform.mk b/plat/imx/imx8m/imx8mp/platform.mk
index 1102316..21836d9 100644
--- a/plat/imx/imx8m/imx8mp/platform.mk
+++ b/plat/imx/imx8m/imx8mp/platform.mk
@@ -32,6 +32,7 @@
 				plat/imx/imx8m/imx_aipstz.c			\
 				plat/imx/imx8m/imx_rdc.c			\
 				plat/imx/imx8m/imx8m_caam.c			\
+				plat/imx/imx8m/imx8m_ccm.c			\
 				plat/imx/imx8m/imx8m_csu.c			\
 				plat/imx/imx8m/imx8m_psci_common.c		\
 				plat/imx/imx8m/imx8mp/imx8mp_bl31_setup.c	\
diff --git a/plat/imx/imx8m/include/imx8m_ccm.h b/plat/imx/imx8m/include/imx8m_ccm.h
new file mode 100644
index 0000000..acbd135
--- /dev/null
+++ b/plat/imx/imx8m/include/imx8m_ccm.h
@@ -0,0 +1,12 @@
+/*
+ * Copyright (c) 2023, Pengutronix. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef IMX8M_CCM_H
+#define IMX8M_CCM_H
+
+unsigned int imx8m_uart_get_base(void);
+
+#endif /* IMX8M_CCM_H */