1 files changed, 161 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 000000000..3cd1b408f
--- /dev/null
+++ b/arch/mips/pic32/pic32mzda/early_console.c
@@ -0,0 +1,161 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Joshua Henderson <joshua.henderson@microchip.com>
+ * Copyright (C) 2015 Microchip Technology Inc.  All rights reserved.
+ */
+#include <asm/mach-pic32/pic32.h>
+#include <asm/fw/fw.h>
+#include <asm/setup.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 int 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(int 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(int 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(void)
+{
+        char *arch_cmdline = pic32_getcmdline();
+        int baud, port;
+
+        uart_base = ioremap(PIC32_BASE_UART, 0xc00);
+
+        baud = get_baud_from_cmdline(arch_cmdline);
+        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);
+}
+
+void 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));
+        }
+}