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