Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus

[linux-drm-fsl-dcu.git] / arch / mips / pic32 / pic32mzda / early_console.c

diff --git a/arch/mips/pic32/pic32mzda/early_console.c b/arch/mips/pic32/pic32mzda/early_console.c
new file mode 100644 (file)
index 0000000..d7b7834
--- /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;
+}