nmhw: add support for late console initialization

- backport from nrsw to support COMIO shield

board/nm/nrhw24/board.c

@@ -1,7 +1,7 @@
 /*
  * board.c
  *
- * Board functions for Netmodule nmhw24 board, based on AM335x EVB
+ * Board functions for Netmodule NRHW 24, based on AM335x EVB
  *
  * Copyright (C) 2018-2019 NetModule AG - http://www.netmodule.com/
  * Copyright (C) 2011, Texas Instruments, Incorporated - http://www.ti.com/
@@ -234,23 +234,29 @@ static inline int __maybe_unused read_eeprom(void)
 
 /*
  * Selects console for SPL.
- * U-Boot console is defined by CONFIG_CONS_INDEX (via menuconfig)
+ * U-Boot console is selected in set_console()
  */
 struct serial_device *default_serial_console(void)
 {
+	/* Mux pins for selected UART properly. 
+	 * Note: uart indexes start at 0 while 
+	 * eserial indexes start at 1. 
+	 */
+
 	/* Provide UART on UART2 regardless of boot mode */
 	enable_uart1_pin_mux();
 	return &eserial2_device;
 
 #if 0	/* TODO: Check whether really required */
-	if (spl_boot_device() == BOOT_DEVICE_UART) {
+	if ((spl_boot_device() == BOOT_DEVICE_UART) || 
+		(spl_boot_device() == BOOT_DEVICE_JTAG)) {
 		enable_uart0_pin_mux();
 		return &eserial1_device;
-	}
-	else {
+	} else {
+		/* Use internal uart, if no output shall be seen. */
 		enable_uart1_pin_mux();
 		return &eserial2_device;
-    }
+	}
 #endif
 }
 
@@ -344,7 +350,7 @@ void am33xx_spl_board_init(void)
 	/* Set CORE Frequencies to OPP100 (600MHz) */
 	do_setup_dpll(&dpll_core_regs, &dpll_core_opp100);
 
-	/* Configure I2C busses */
+	/* Configure both I2C buses used */
 	init_i2c();
 
 	/* Setup PMIC */
@@ -374,7 +380,6 @@ const struct dpll_params *get_dpll_ddr_params(void)
 
 void set_uart_mux_conf(void)
 {
-	/* TODO: Set depending on boot mode (SPL/UBoot, eMMC/UART) */
 	enable_uart0_pin_mux();
 	enable_uart1_pin_mux();
 }
@@ -453,7 +458,7 @@ static void init_ethernet(void)
 static void init_sim_mux(void)
 {
 	/*
-	 * Switch onboard SIM to onboard modem (Mux = 1)
+	 * Switch pluggable micro SIM to onboard modem (mux = 0)
 	 */
 	REQUEST_AND_CLEAR_GPIO(GPIO_SIM_SEL);
 }
@@ -533,7 +538,7 @@ int board_init(void)
 
 	gd->bd->bi_boot_params = CONFIG_SYS_SDRAM_BASE + 0x100;
 
-	/* Configure I2C busses */
+	/* Configure both I2C buses used */
 	init_i2c();
 
 	da9063_init(CONFIG_PMIC_I2C_BUS);
@@ -550,28 +555,60 @@ int board_init(void)
 
 #if !defined(CONFIG_SPL_BUILD)
 
+/* TODO: Move to top of file or place into header file */
+extern int console_init_f(void);
+extern void serial_set_console_index(int index);
+
+/*
+ * Set Linux console based on
+ * - Selection in /root/boot/consoledev
+ * - Available tty interfaces
+ *   - ttyS1: standard console (default, internal only)
+ *   - ttyS0: COMIO shield (or used as console by kernel, 
+ *            when no other console available)
+ *   - ttyNull0: Dummy device if no real UART is available
+ */
 void set_console(void)
 {
 	const char *defaultconsole = getenv("defaultconsole");
 
-	if (defaultconsole == 0) {
-		/* Use the default console */
-		setenv("defaultconsole", "ttyS1");
-	}
-
-#if 0
-	const char *defaultconsole = getenv("defaultconsole");
-	char buf[8];
-
 	/* Set default console to ttyS1 if not yet defined in env */
 	if (defaultconsole == 0) {
 		setenv("defaultconsole", "ttyS1");
 	}
 
+	/* Always use internal console for u-boot
+		as comio shield is not ready at that time.
+		(Needs to be initialized first using the
+		shieldcmd that is run by bootcmd.) */
+	serial_set_console_index(1);
+
+#if defined(CONFIG_PRE_CONSOLE_BUFFER)
+	serial_init(); /* serial communications setup */
+	console_init_f(); /* stage 1 init of console */
+#endif
+
+#if 0
+	if (shield_id != SHIELD_COM_IO) {
+		/* Don't allow changing to ttyS0 for the kernel console, because
+		 * ttyS0 is not available if no comio shield is populated. */
+		return;
+	}
+
+	/* With comio shield the defaultconsole for the kernel should
+	be ttyS0 and not ttyS1 */
+	setenv("defaultconsole", "ttyS0");
+
 	/* If consoledev file is present, take the tty defined in it as console */
-	if (read_file("/root/boot/consoledev",buf, 5) == 5) {
+	if (read_file("/root/boot/consoledev",buf, sizeof(buf)) > 3) {
 		if (strstr(buf, "tty") == buf) {
-			buf[5] = 0;
+			buf[sizeof(buf)-1] = 0;
+			for (i=0; i<sizeof(buf); i++) {
+				if (buf[i]<=' ') {
+					buf[i] = 0;
+					break;
+				}
+			}
 			setenv("defaultconsole", buf);
 		}
 	}
@@ -674,6 +711,7 @@ static void check_fct(void)
 	i2c_set_bus_num(old_bus);
 }
 
+
 struct shield_command {
 	int shield_id;
 	const char *name;
@@ -752,7 +790,6 @@ static void shield_init(void)
 	shield_config();
 }
 
-
 static bool get_button_state(void)
 {
 	uint8_t state = 0x00;

common/board_f.c

@@ -888,8 +888,10 @@ static init_fnc_t init_sequence_f[] = {
 	init_timebase,
 #endif
 	init_baud_rate,		/* initialze baudrate settings */
+#if !defined(CONFIG_PRE_CONSOLE_BUFFER)
 	serial_init,		/* serial communications setup */
 	console_init_f,		/* stage 1 init of console */
+#endif
 #ifdef CONFIG_SANDBOX
 	sandbox_early_getopt_check,
 #endif

common/console.c

@@ -414,7 +414,7 @@ int tstc(void)
 #define PRE_CONSOLE_FLUSHPOINT2_EVERYTHING_BUT_SERIAL	1
 
 #ifdef CONFIG_PRE_CONSOLE_BUFFER
-#define CIRC_BUF_IDX(idx) ((idx) % (unsigned long)CONFIG_PRE_CON_BUF_SZ)
+#define CIRC_BUF_IDX(idx) ((idx) % (unsigned long)(CONFIG_PRE_CON_BUF_SZ))
 
 static void pre_console_putc(const char c)
 {

drivers/serial/serial-uclass.c

@@ -27,6 +27,20 @@ static const unsigned long baudrate_table[] = CONFIG_SYS_BAUDRATE_TABLE;
 #error "Serial is required before relocation - define CONFIG_SYS_MALLOC_F_LEN to make this work"
 #endif
 
+#ifdef CONFIG_CONS_INDEX
+static int console_index = CONFIG_CONS_INDEX - 1;
+#else
+static int console_index = 0;
+#endif
+
+/* TODO: Rename CONSOLE_INDEX to console_index, to make clear it
+ * is a variable now
+ */
+void serial_set_console_index(int index)
+{
+	console_index = index;
+}
+
 static void serial_find_console_or_panic(void)
 {
 	const void *blob = gd->fdt_blob;
@@ -84,18 +98,12 @@ static void serial_find_console_or_panic(void)
 		 * extremis just the first serial device we can find. But we
 		 * insist on having a console (even if it is silent).
 		 */
-#ifdef CONFIG_CONS_INDEX
-#define INDEX (CONFIG_CONS_INDEX - 1)
-#else
-#define INDEX 0
-#endif
-		if (!uclass_get_device_by_seq(UCLASS_SERIAL, INDEX, &dev) ||
-		    !uclass_get_device(UCLASS_SERIAL, INDEX, &dev) ||
+		if (!uclass_get_device_by_seq(UCLASS_SERIAL, console_index, &dev) ||
+		    !uclass_get_device(UCLASS_SERIAL, console_index, &dev) ||
 		    (!uclass_first_device(UCLASS_SERIAL, &dev) && dev)) {
 			gd->cur_serial_dev = dev;
 			return;
 		}
-#undef INDEX
 	}
 
 #ifdef CONFIG_REQUIRE_SERIAL_CONSOLE
@@ -115,7 +123,9 @@ int serial_init(void)
 /* Called after relocation */
 void serial_initialize(void)
 {
+#if !defined(CONFIG_PRE_CONSOLE_BUFFER)
 	serial_init();
+#endif
 }
 
 static void _serial_putc(struct udevice *dev, char ch)

include/configs/am335x_nrhw24.h

@@ -36,6 +36,10 @@
 #define CONFIG_MACH_TYPE		MACH_TYPE_TIAM335EVM
 #define CONFIG_BOARD_LATE_INIT
 
+#define CONFIG_PRE_CONSOLE_BUFFER
+#define CONFIG_PRE_CON_BUF_ADDR   0x80000000
+#define CONFIG_PRE_CON_BUF_SZ     64*1024
+
 /* Clock Defines */
 #define V_OSCK				0 /* 0 means detect from sysboot1 config */
 #define V_SCLK				(V_OSCK)