From 676a154ec4ea3b8836a61b279ca08dc9e4eb761d Mon Sep 17 00:00:00 2001 From: Georgi Djakov Date: Fri, 6 Feb 2015 13:08:50 +0200 Subject: Revert "arm64: remove arch specific earlyprintk" This reverts commit 8ef0ed95ee040a5cd25325dddcb8292c34bec33e. Conflicts: arch/arm64/kernel/Makefile Signed-off-by: Georgi Djakov --- arch/arm64/Kconfig.debug | 9 +++ arch/arm64/kernel/Makefile | 1 + arch/arm64/kernel/early_printk.c | 158 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 168 insertions(+) create mode 100644 arch/arm64/kernel/early_printk.c diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug index 4a8741073c9..d6ba752e8d1 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -32,6 +32,15 @@ config STRICT_DEVMEM If in doubt, say Y. +config EARLY_PRINTK + bool "Early printk support" + default y + help + Say Y here if you want to have an early console using the + earlyprintk=[,][,] kernel parameter. It + is assumed that the early console device has been initialised + by the boot loader prior to starting the Linux kernel. + config PID_IN_CONTEXTIDR bool "Write the current PID to the CONTEXTIDR register" help diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index bef04afd603..169c429e63e 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -29,6 +29,7 @@ arm64-obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT) += hw_breakpoint.o arm64-obj-$(CONFIG_CPU_PM) += sleep.o suspend.o arm64-obj-$(CONFIG_CPU_IDLE) += cpuidle.o +arm64-obj-$(CONFIG_EARLY_PRINTK) += early_printk.o arm64-obj-$(CONFIG_JUMP_LABEL) += jump_label.o arm64-obj-$(CONFIG_KGDB) += kgdb.o arm64-obj-$(CONFIG_EFI) += efi.o efi-stub.o efi-entry.o diff --git a/arch/arm64/kernel/early_printk.c b/arch/arm64/kernel/early_printk.c new file mode 100644 index 00000000000..ffbbdde7aba --- /dev/null +++ b/arch/arm64/kernel/early_printk.c @@ -0,0 +1,158 @@ +/* + * Earlyprintk support. + * + * Copyright (C) 2012 ARM Ltd. + * Author: Catalin Marinas + * + * This program is free software: you can redistribute 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 that 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. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see . + */ +#include +#include +#include +#include +#include +#include + +#include +#include + +#include + +static void __iomem *early_base; +static void (*printch)(char ch); + +/* + * PL011 single character TX. + */ +static void pl011_printch(char ch) +{ + while (readl_relaxed(early_base + UART01x_FR) & UART01x_FR_TXFF) + ; + writeb_relaxed(ch, early_base + UART01x_DR); + while (readl_relaxed(early_base + UART01x_FR) & UART01x_FR_BUSY) + ; +} + +/* + * Semihosting-based debug console + */ +static void smh_printch(char ch) +{ + asm volatile("mov x1, %0\n" + "mov x0, #3\n" + "hlt 0xf000\n" + : : "r" (&ch) : "x0", "x1", "memory"); +} + +/* + * 8250/16550 (8-bit aligned registers) single character TX. + */ +static void uart8250_8bit_printch(char ch) +{ + while (!(readb_relaxed(early_base + UART_LSR) & UART_LSR_THRE)) + ; + writeb_relaxed(ch, early_base + UART_TX); +} + +/* + * 8250/16550 (32-bit aligned registers) single character TX. + */ +static void uart8250_32bit_printch(char ch) +{ + while (!(readl_relaxed(early_base + (UART_LSR << 2)) & UART_LSR_THRE)) + ; + writel_relaxed(ch, early_base + (UART_TX << 2)); +} + +struct earlycon_match { + const char *name; + void (*printch)(char ch); +}; + +static const struct earlycon_match earlycon_match[] __initconst = { + { .name = "pl011", .printch = pl011_printch, }, + { .name = "smh", .printch = smh_printch, }, + { .name = "uart8250-8bit", .printch = uart8250_8bit_printch, }, + { .name = "uart8250-32bit", .printch = uart8250_32bit_printch, }, + {} +}; + +static void early_write(struct console *con, const char *s, unsigned n) +{ + while (n-- > 0) { + if (*s == '\n') + printch('\r'); + printch(*s); + s++; + } +} + +static struct console early_console_dev = { + .name = "earlycon", + .write = early_write, + .flags = CON_PRINTBUFFER | CON_BOOT, + .index = -1, +}; + +/* + * Parse earlyprintk=... parameter in the format: + * + * [,][,] + * + * and register the early console. It is assumed that the UART has been + * initialised by the bootloader already. + */ +static int __init setup_early_printk(char *buf) +{ + const struct earlycon_match *match = earlycon_match; + phys_addr_t paddr = 0; + + if (!buf) { + pr_warning("No earlyprintk arguments passed.\n"); + return 0; + } + + while (match->name) { + size_t len = strlen(match->name); + if (!strncmp(buf, match->name, len)) { + buf += len; + break; + } + match++; + } + if (!match->name) { + pr_warning("Unknown earlyprintk arguments: %s\n", buf); + return 0; + } + + /* I/O address */ + if (!strncmp(buf, ",0x", 3)) { + char *e; + paddr = simple_strtoul(buf + 1, &e, 16); + buf = e; + } + /* no options parsing yet */ + + if (paddr) { + set_fixmap_io(FIX_EARLYCON_MEM_BASE, paddr); + early_base = (void __iomem *)fix_to_virt(FIX_EARLYCON_MEM_BASE); + } + + printch = match->printch; + early_console = &early_console_dev; + register_console(&early_console_dev); + + return 0; +} + +early_param("earlyprintk", setup_early_printk); -- cgit v1.2.3