From b69b9aadc91047ecb0320df414b86ed02ba3f717 Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Tue, 5 May 2015 13:13:36 +0200 Subject: [PATCH] console: Fix pre-console flushing via cfb_console being very slow On my A10 OlinuxIno Lime I noticed a huge (5+ seconds) delay coming from console_init_r. This turns out to be caused by the preconsole buffer flushing to the cfb_console. The Lime only has a 16 bit memory bus and that is already heavy used to scan out the 1920x1080 framebuffer. The problem is that print_pre_console_buffer() was printing the buffer once character at a time and the cfb_console code then ends up doing a cache-flush for touched display lines for each character. This commit fixes this by first building a 0 terminated buffer and then printing it in one puts() call, avoiding unnecessary cache flushes. This changes the time for the flush from 5+ seconds to not noticable. The downside of this approach is that the pre-console buffer needs to fit on the stack, this is not that much to ask since we are talking about plain text here. This commit also adjusts the sunxi CONFIG_PRE_CON_BUF_SZ to actually fit on the stack. Sunxi currently is the only user of the pre-console code so no other boards need to be adjusted. Signed-off-by: Hans de Goede Reviewed-by: Tom Rini --- README | 3 +++ common/console.c | 40 +++++++++++++++++++--------------- include/configs/sunxi-common.h | 2 +- 3 files changed, 26 insertions(+), 19 deletions(-) diff --git a/README b/README index d0869a8b55..c56001cdec 100644 --- a/README +++ b/README @@ -1058,6 +1058,9 @@ The following options need to be configured: bytes are output before the console is initialised, the earlier bytes are discarded. + Note that when printing the buffer a copy is made on the + stack so CONFIG_PRE_CON_BUF_SZ must fit on the stack. + 'Sane' compilers will generate smaller code if CONFIG_PRE_CON_BUF_SZ is a power of 2 diff --git a/common/console.c b/common/console.c index 3f25e76fe7..00582224d4 100644 --- a/common/console.c +++ b/common/console.c @@ -200,15 +200,15 @@ static void console_putc(int file, const char c) } #ifdef CONFIG_PRE_CONSOLE_BUFFER -static void console_putc_noserial(int file, const char c) +static void console_puts_noserial(int file, const char *s) { int i; struct stdio_dev *dev; for (i = 0; i < cd_count[file]; i++) { dev = console_devices[file][i]; - if (dev->putc != NULL && strcmp(dev->name, "serial") != 0) - dev->putc(dev, c); + if (dev->puts != NULL && strcmp(dev->name, "serial") != 0) + dev->puts(dev, s); } } #endif @@ -251,10 +251,10 @@ static inline void console_putc(int file, const char c) } #ifdef CONFIG_PRE_CONSOLE_BUFFER -static inline void console_putc_noserial(int file, const char c) +static inline void console_puts_noserial(int file, const char *s) { if (strcmp(stdio_devices[file]->name, "serial") != 0) - stdio_devices[file]->putc(stdio_devices[file], c); + stdio_devices[file]->puts(stdio_devices[file], s); } #endif @@ -425,22 +425,26 @@ static void pre_console_puts(const char *s) static void print_pre_console_buffer(int flushpoint) { - unsigned long i = 0; - char *buffer = (char *)CONFIG_PRE_CON_BUF_ADDR; + unsigned long in = 0, out = 0; + char *buf_in = (char *)CONFIG_PRE_CON_BUF_ADDR; + char buf_out[CONFIG_PRE_CON_BUF_SZ + 1]; if (gd->precon_buf_idx > CONFIG_PRE_CON_BUF_SZ) - i = gd->precon_buf_idx - CONFIG_PRE_CON_BUF_SZ; + in = gd->precon_buf_idx - CONFIG_PRE_CON_BUF_SZ; - while (i < gd->precon_buf_idx) - switch (flushpoint) { - case PRE_CONSOLE_FLUSHPOINT1_SERIAL: - putc(buffer[CIRC_BUF_IDX(i++)]); - break; - case PRE_CONSOLE_FLUSHPOINT2_EVERYTHING_BUT_SERIAL: - console_putc_noserial(stdout, - buffer[CIRC_BUF_IDX(i++)]); - break; - } + while (in < gd->precon_buf_idx) + buf_out[out++] = buf_in[CIRC_BUF_IDX(in++)]; + + buf_out[out] = 0; + + switch (flushpoint) { + case PRE_CONSOLE_FLUSHPOINT1_SERIAL: + puts(buf_out); + break; + case PRE_CONSOLE_FLUSHPOINT2_EVERYTHING_BUT_SERIAL: + console_puts_noserial(stdout, buf_out); + break; + } } #else static inline void pre_console_putc(const char c) {} diff --git a/include/configs/sunxi-common.h b/include/configs/sunxi-common.h index 723067ea74..0495dc3b8c 100644 --- a/include/configs/sunxi-common.h +++ b/include/configs/sunxi-common.h @@ -336,7 +336,7 @@ extern int soft_i2c_gpio_scl; /* Enable pre-console buffer to get complete log on the VGA console */ #define CONFIG_PRE_CONSOLE_BUFFER -#define CONFIG_PRE_CON_BUF_SZ (1024 * 1024) +#define CONFIG_PRE_CON_BUF_SZ 4096 /* Aprox 2 80*25 screens */ /* Use the room between the end of bootm_size and the framebuffer */ #define CONFIG_PRE_CON_BUF_ADDR 0x4f000000 -- 2.39.2