From: Robin Getz Date: Tue, 9 Oct 2007 09:24:49 +0000 (+0800) Subject: Blackfin arch: Initial patch to add earlyprintk support X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=0ae53640b54f2c30e52044f7102ba08915b988a7;p=linux-2.6 Blackfin arch: Initial patch to add earlyprintk support This allows debugging of problems which happen eary in the kernel boot process (after bootargs are parsed, but before serial subsystem is fully initialized) Signed-off-by: Robin Getz Signed-off-by: Bryan Wu --- diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 4d175c7512..a57c1f216b 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -35,6 +35,7 @@ parameter is applicable: APIC APIC support is enabled. APM Advanced Power Management support is enabled. AX25 Appropriate AX.25 support is enabled. + BLACKFIN Blackfin architecture is enabled. DRM Direct Rendering Management support is enabled. EDD BIOS Enhanced Disk Drive Services (EDD) is enabled EFI EFI Partitioning (GPT) is enabled @@ -550,7 +551,7 @@ and is between 256 and 4096 characters. It is defined in the file dtc3181e= [HW,SCSI] - earlyprintk= [X86-32,X86-64,SH] + earlyprintk= [X86-32,X86-64,SH,BLACKFIN] earlyprintk=vga earlyprintk=serial[,ttySn[,baudrate]] diff --git a/arch/blackfin/Kconfig b/arch/blackfin/Kconfig index 26ebb0e8c4..cc789b988f 100644 --- a/arch/blackfin/Kconfig +++ b/arch/blackfin/Kconfig @@ -1164,6 +1164,20 @@ config DEBUG_BFIN_NO_KERN_HWTRACE Say Y here to disable hardware tracing in some known "jumpy" pieces of code so that the trace buffer will extend further back. +config EARLY_PRINTK + bool "Early printk" + default n + help + This option enables special console drivers which allow the kernel + to print messages very early in the bootup process. + + This is useful for kernel debugging when your machine crashes very + early before the console code is initialized. After enabling this + feature, you must add "earlyprintk=serial,uart0,57600" to the + command line (bootargs). It is safe to say Y here in all cases, as + all of this lives in the init section and is thrown away after the + kernel boots completely. + config DUAL_CORE_TEST_MODULE tristate "Dual Core Test Module" depends on (BF561) diff --git a/arch/blackfin/kernel/Makefile b/arch/blackfin/kernel/Makefile index 243883ec6d..8aeb6066b1 100644 --- a/arch/blackfin/kernel/Makefile +++ b/arch/blackfin/kernel/Makefile @@ -13,3 +13,4 @@ obj-$(CONFIG_MODULES) += module.o obj-$(CONFIG_BFIN_DMA_5XX) += bfin_dma_5xx.o obj-$(CONFIG_DUAL_CORE_TEST_MODULE) += dualcore_test.o obj-$(CONFIG_KGDB) += kgdb.o +obj-$(CONFIG_EARLY_PRINTK) += early_printk.o diff --git a/arch/blackfin/kernel/early_printk.c b/arch/blackfin/kernel/early_printk.c new file mode 100644 index 0000000000..9bf6170669 --- /dev/null +++ b/arch/blackfin/kernel/early_printk.c @@ -0,0 +1,161 @@ +/* + * File: arch/blackfin/kernel/early_printk.c + * Based on: arch/x86_64/kernel/early_printk.c + * Author: Robin Getz +#include +#include +#include +#include +#include +#include +#include + +#ifdef CONFIG_SERIAL_BFIN +extern struct console *bfin_earlyserial_init(unsigned int port, + unsigned int cflag); +#endif + +static struct console *early_console; + +/* Default console + * Port n == ttyBFn + * cflags == UART output modes + */ +#define DEFAULT_PORT 0 +#define DEFAULT_CFLAG CS8|B57600 + +#ifdef CONFIG_SERIAL_CORE +/* What should get here is "0,57600" */ +static struct console * __init earlyserial_init(char *buf) +{ + int baud, bit; + char parity; + unsigned int serial_port = DEFAULT_PORT; + unsigned int cflag = DEFAULT_CFLAG; + + serial_port = simple_strtoul(buf, &buf, 10); + buf++; + + cflag = 0; + baud = simple_strtoul(buf, &buf, 10); + switch (baud) { + case 1200: + cflag |= B1200; + break; + case 2400: + cflag |= B2400; + break; + case 4800: + cflag |= B4800; + break; + case 9600: + cflag |= B9600; + break; + case 19200: + cflag |= B19200; + break; + case 38400: + cflag |= B38400; + break; + case 115200: + cflag |= B115200; + break; + default: + cflag |= B57600; + } + + parity = buf[0]; + buf++; + switch (parity) { + case 'e': + cflag |= PARENB; + break; + case 'o': + cflag |= PARODD; + break; + } + + bit = simple_strtoul(buf, &buf, 10); + switch (bit) { + case 5: + cflag |= CS5; + break; + case 6: + cflag |= CS5; + break; + case 7: + cflag |= CS5; + break; + default: + cflag |= CS8; + } + +#ifdef CONFIG_SERIAL_BFIN + return bfin_earlyserial_init(serial_port, cflag); +#else + return NULL; +#endif + +} +#endif + +int __init setup_early_printk(char *buf) +{ + + /* Crashing in here would be really bad, so check both the var + and the pointer before we start using it + */ + if (!buf) + return 0; + + if (!*buf) + return 0; + + if (early_console != NULL) + return 0; + +#ifdef CONFIG_SERIAL_BFIN + /* Check for Blackfin Serial */ + if (!strncmp(buf, "serial,uart", 11)) { + buf += 11; + early_console = earlyserial_init(buf); + } +#endif +#ifdef CONFIG_FB + /* TODO: add framebuffer console support */ +#endif + + if (likely(early_console)) { + early_console->flags |= CON_BOOT; + + register_console(early_console); + printk(KERN_INFO "early printk enabled on %s%d\n", + early_console->name, + early_console->index); + } + + return 0; +} + +early_param("earlyprintk", setup_early_printk); diff --git a/drivers/serial/bfin_5xx.c b/drivers/serial/bfin_5xx.c index 1e79ee605d..5039e2675a 100644 --- a/drivers/serial/bfin_5xx.c +++ b/drivers/serial/bfin_5xx.c @@ -962,30 +962,6 @@ static void __init bfin_serial_init_ports(void) } #ifdef CONFIG_SERIAL_BFIN_CONSOLE -static void bfin_serial_console_putchar(struct uart_port *port, int ch) -{ - struct bfin_serial_port *uart = (struct bfin_serial_port *)port; - while (!(UART_GET_LSR(uart) & THRE)) - barrier(); - UART_PUT_CHAR(uart, ch); - SSYNC(); -} - -/* - * Interrupts are disabled on entering - */ -static void -bfin_serial_console_write(struct console *co, const char *s, unsigned int count) -{ - struct bfin_serial_port *uart = &bfin_serial_ports[co->index]; - int flags = 0; - - spin_lock_irqsave(&uart->port.lock, flags); - uart_console_write(&uart->port, s, count, bfin_serial_console_putchar); - spin_unlock_irqrestore(&uart->port.lock, flags); - -} - /* * If the port was already initialised (eg, by a boot loader), * try to determine the current setup. @@ -1038,19 +1014,25 @@ bfin_serial_console_get_options(struct bfin_serial_port *uart, int *baud, } pr_debug("%s:baud = %d, parity = %c, bits= %d\n", __FUNCTION__, *baud, *parity, *bits); } +#endif + +#if defined(CONFIG_SERIAL_BFIN_CONSOLE) || defined(CONFIG_EARLY_PRINTK) +static struct uart_driver bfin_serial_reg; static int __init bfin_serial_console_setup(struct console *co, char *options) { struct bfin_serial_port *uart; +# ifdef CONFIG_SERIAL_BFIN_CONSOLE int baud = 57600; int bits = 8; int parity = 'n'; -#ifdef CONFIG_SERIAL_BFIN_CTSRTS +# ifdef CONFIG_SERIAL_BFIN_CTSRTS int flow = 'r'; -#else +# else int flow = 'n'; -#endif +# endif +# endif /* * Check whether an invalid uart number has been specified, and @@ -1061,15 +1043,45 @@ bfin_serial_console_setup(struct console *co, char *options) co->index = 0; uart = &bfin_serial_ports[co->index]; +# ifdef CONFIG_SERIAL_BFIN_CONSOLE if (options) uart_parse_options(options, &baud, &parity, &bits, &flow); else bfin_serial_console_get_options(uart, &baud, &parity, &bits); return uart_set_options(&uart->port, co, baud, parity, bits, flow); +# else + return 0; +# endif +} +#endif /* defined (CONFIG_SERIAL_BFIN_CONSOLE) || + defined (CONFIG_EARLY_PRINTK) */ + +#ifdef CONFIG_SERIAL_BFIN_CONSOLE +static void bfin_serial_console_putchar(struct uart_port *port, int ch) +{ + struct bfin_serial_port *uart = (struct bfin_serial_port *)port; + while (!(UART_GET_LSR(uart) & THRE)) + barrier(); + UART_PUT_CHAR(uart, ch); + SSYNC(); +} + +/* + * Interrupts are disabled on entering + */ +static void +bfin_serial_console_write(struct console *co, const char *s, unsigned int count) +{ + struct bfin_serial_port *uart = &bfin_serial_ports[co->index]; + int flags = 0; + + spin_lock_irqsave(&uart->port.lock, flags); + uart_console_write(&uart->port, s, count, bfin_serial_console_putchar); + spin_unlock_irqrestore(&uart->port.lock, flags); + } -static struct uart_driver bfin_serial_reg; static struct console bfin_serial_console = { .name = BFIN_SERIAL_NAME, .write = bfin_serial_console_write, @@ -1095,7 +1107,68 @@ console_initcall(bfin_serial_rs_console_init); #define BFIN_SERIAL_CONSOLE &bfin_serial_console #else #define BFIN_SERIAL_CONSOLE NULL +#endif /* CONFIG_SERIAL_BFIN_CONSOLE */ + + +#ifdef CONFIG_EARLY_PRINTK +static __init void early_serial_putc(struct uart_port *port, int ch) +{ + unsigned timeout = 0xffff; + struct bfin_serial_port *uart = (struct bfin_serial_port *)port; + + while ((!(UART_GET_LSR(uart) & THRE)) && --timeout) + cpu_relax(); + UART_PUT_CHAR(uart, ch); +} + +static __init void early_serial_write(struct console *con, const char *s, + unsigned int n) +{ + struct bfin_serial_port *uart = &bfin_serial_ports[con->index]; + unsigned int i; + + for (i = 0; i < n; i++, s++) { + if (*s == '\n') + early_serial_putc(&uart->port, '\r'); + early_serial_putc(&uart->port, *s); + } +} + +static struct __init console bfin_early_serial_console = { + .name = "early_BFuart", + .write = early_serial_write, + .device = uart_console_device, + .flags = CON_PRINTBUFFER, + .setup = bfin_serial_console_setup, + .index = -1, + .data = &bfin_serial_reg, +}; + +struct console __init *bfin_earlyserial_init(unsigned int port, + unsigned int cflag) +{ + struct bfin_serial_port *uart; + struct ktermios t; + + if (port == -1 || port >= nr_ports) + port = 0; + bfin_serial_init_ports(); + bfin_early_serial_console.index = port; +#ifdef CONFIG_KGDB_UART + kgdb_entry_state = 0; + init_kgdb_uart(); #endif + uart = &bfin_serial_ports[port]; + t.c_cflag = cflag; + t.c_iflag = 0; + t.c_oflag = 0; + t.c_lflag = ICANON; + t.c_line = port; + bfin_serial_set_termios(&uart->port, &t, &t); + return &bfin_early_serial_console; +} + +#endif /* CONFIG_SERIAL_BFIN_CONSOLE */ static struct uart_driver bfin_serial_reg = { .owner = THIS_MODULE, diff --git a/include/asm-blackfin/early_printk.h b/include/asm-blackfin/early_printk.h new file mode 100644 index 0000000000..110f1c1f84 --- /dev/null +++ b/include/asm-blackfin/early_printk.h @@ -0,0 +1,28 @@ +/* + * File: include/asm-blackfin/early_printk.h + * Author: Robin Getz