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Diffstat (limited to 'arch/mips/pic32/pic32mzda/early_console.c')
-rw-r--r--arch/mips/pic32/pic32mzda/early_console.c171
1 files changed, 171 insertions, 0 deletions
diff --git a/arch/mips/pic32/pic32mzda/early_console.c b/arch/mips/pic32/pic32mzda/early_console.c
new file mode 100644
index 000000000000..d7b783463fac
--- /dev/null
+++ b/arch/mips/pic32/pic32mzda/early_console.c
@@ -0,0 +1,171 @@
+/*
+ * Joshua Henderson <joshua.henderson@microchip.com>
+ * Copyright (C) 2015 Microchip Technology Inc. All rights reserved.
+ *
+ * This program is free software; you can distribute it and/or modify it
+ * under the terms of the GNU General Public License (Version 2) as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
+ * for more details.
+ */
+#include <asm/mach-pic32/pic32.h>
+#include <asm/fw/fw.h>
+
+#include "pic32mzda.h"
+#include "early_pin.h"
+
+/* Default early console parameters */
+#define EARLY_CONSOLE_PORT 1
+#define EARLY_CONSOLE_BAUDRATE 115200
+
+#define UART_ENABLE BIT(15)
+#define UART_ENABLE_RX BIT(12)
+#define UART_ENABLE_TX BIT(10)
+#define UART_TX_FULL BIT(9)
+
+/* UART1(x == 0) - UART6(x == 5) */
+#define UART_BASE(x) ((x) * 0x0200)
+#define U_MODE(x) UART_BASE(x)
+#define U_STA(x) (UART_BASE(x) + 0x10)
+#define U_TXR(x) (UART_BASE(x) + 0x20)
+#define U_BRG(x) (UART_BASE(x) + 0x40)
+
+static void __iomem *uart_base;
+static char console_port = -1;
+
+static int __init configure_uart_pins(int port)
+{
+ switch (port) {
+ case 1:
+ pic32_pps_input(IN_FUNC_U2RX, IN_RPB0);
+ pic32_pps_output(OUT_FUNC_U2TX, OUT_RPG9);
+ break;
+ case 5:
+ pic32_pps_input(IN_FUNC_U6RX, IN_RPD0);
+ pic32_pps_output(OUT_FUNC_U6TX, OUT_RPB8);
+ break;
+ default:
+ return -1;
+ }
+
+ return 0;
+}
+
+static void __init configure_uart(char port, int baud)
+{
+ u32 pbclk;
+
+ pbclk = pic32_get_pbclk(2);
+
+ __raw_writel(0, uart_base + U_MODE(port));
+ __raw_writel(((pbclk / baud) / 16) - 1, uart_base + U_BRG(port));
+ __raw_writel(UART_ENABLE, uart_base + U_MODE(port));
+ __raw_writel(UART_ENABLE_TX | UART_ENABLE_RX,
+ uart_base + PIC32_SET(U_STA(port)));
+}
+
+static void __init setup_early_console(char port, int baud)
+{
+ if (configure_uart_pins(port))
+ return;
+
+ console_port = port;
+ configure_uart(console_port, baud);
+}
+
+static char * __init pic32_getcmdline(void)
+{
+ /*
+ * arch_mem_init() has not been called yet, so we don't have a real
+ * command line setup if using CONFIG_CMDLINE_BOOL.
+ */
+#ifdef CONFIG_CMDLINE_OVERRIDE
+ return CONFIG_CMDLINE;
+#else
+ return fw_getcmdline();
+#endif
+}
+
+static int __init get_port_from_cmdline(char *arch_cmdline)
+{
+ char *s;
+ int port = -1;
+
+ if (!arch_cmdline || *arch_cmdline == '\0')
+ goto _out;
+
+ s = strstr(arch_cmdline, "earlyprintk=");
+ if (s) {
+ s = strstr(s, "ttyS");
+ if (s)
+ s += 4;
+ else
+ goto _out;
+
+ port = (*s) - '0';
+ }
+
+_out:
+ return port;
+}
+
+static int __init get_baud_from_cmdline(char *arch_cmdline)
+{
+ char *s;
+ int baud = -1;
+
+ if (!arch_cmdline || *arch_cmdline == '\0')
+ goto _out;
+
+ s = strstr(arch_cmdline, "earlyprintk=");
+ if (s) {
+ s = strstr(s, "ttyS");
+ if (s)
+ s += 6;
+ else
+ goto _out;
+
+ baud = 0;
+ while (*s >= '0' && *s <= '9')
+ baud = baud * 10 + *s++ - '0';
+ }
+
+_out:
+ return baud;
+}
+
+void __init fw_init_early_console(char port)
+{
+ char *arch_cmdline = pic32_getcmdline();
+ int baud = -1;
+
+ uart_base = ioremap_nocache(PIC32_BASE_UART, 0xc00);
+
+ baud = get_baud_from_cmdline(arch_cmdline);
+ if (port == -1)
+ port = get_port_from_cmdline(arch_cmdline);
+
+ if (port == -1)
+ port = EARLY_CONSOLE_PORT;
+
+ if (baud == -1)
+ baud = EARLY_CONSOLE_BAUDRATE;
+
+ setup_early_console(port, baud);
+}
+
+int prom_putchar(char c)
+{
+ if (console_port >= 0) {
+ while (__raw_readl(
+ uart_base + U_STA(console_port)) & UART_TX_FULL)
+ ;
+
+ __raw_writel(c, uart_base + U_TXR(console_port));
+ }
+
+ return 1;
+}