x86: Add CBMEM console driver for coreboot

This patch builds upon the recently introduced CBMEM console
feature of coreboot.

CBMEM console uses a memry area allocated by coreboot to store
the console output. The memory area has a certain structure,
which allows to determine where the buffer is, the buffer size
and the location of the pointer in the buffer. This allows
different phases of the firmware (rom based coreboot, ram based
coreboot, u-boot after relocation with this change) to keep
adding text to the same buffer.

Note that this patch introduces a new console driver and adds the
driver to the list of drivers to be used for console output, i.e.
it engages only after u-boot relocates. Usiong CBMEM console for
capturing the pre-relocation console output will be done under a
separate change.

>From Linux, run the cbmem.py utility (which is a part of the coreboot
package) to see the output, e.g.:

vvvvvvvvvvvvvvvvv
SCSI:  AHCI 0001.0300 32 slots 6 ports ? Gbps 0xf impl SATA mode
flags: 64bit ilck stag led pmp pio
...
Magic signature found
Kernel command line: "cros_secure  quiet loglevel=1 console=tty2...
^^^^^^^^^^^^^^^^^

Note that the entire u-boot output fits into the buffer only if
the coreboot log level is reduced from the most verbose. Ether
the buffer size will have to be increased, or the coreboot
verbosity permanently reduced.

Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Signed-off-by: Simon Glass <sjg@chromium.org>

diff --git a/common/stdio.c b/common/stdio.c
index 605ff3fde3ea30e1f631043ea5003557360689c0..9f48e5f5034da70cda786d8569a7287780868c9c 100644 (file)
--- a/common/stdio.c
+++ b/common/stdio.c
@@ -237,6 +237,8 @@ int stdio_init (void)
 #ifdef CONFIG_JTAG_CONSOLE
        drv_jtag_console_init ();
 #endif
-
+#ifdef CONFIG_CBMEM_CONSOLE
+       cbmemc_init();
+#endif
        return (0);
 }

diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index 1f035e6d12ba3c036946a4208a8bd1a6160cf5b8..8cdc3b649ca34a963efe314da8731642914a684b 100644 (file)
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -27,6 +27,7 @@ LIB   := $(obj)libmisc.o
 
 COBJS-$(CONFIG_ALI152X) += ali512x.o
 COBJS-$(CONFIG_DS4510)  += ds4510.o
+COBJS-$(CONFIG_CBMEM_CONSOLE) += cbmem_console.o
 COBJS-$(CONFIG_GPIO_LED) += gpio_led.o
 COBJS-$(CONFIG_FSL_MC9SDZ60) += mc9sdz60.o
 COBJS-$(CONFIG_NS87308) += ns87308.o

diff --git a/include/stdio_dev.h b/include/stdio_dev.h
index 23e0ee15f280d1dba02fbe99e61915606d97866b..932d093345e59ade1c175b13fe677dfdcee935dc 100644 (file)
--- a/include/stdio_dev.h
+++ b/include/stdio_dev.h
@@ -120,5 +120,8 @@ int drv_nc_init (void);
 #ifdef CONFIG_JTAG_CONSOLE
 int drv_jtag_console_init (void);
 #endif
+#ifdef CONFIG_CBMEM_CONSOLE
+int cbmemc_init(void);
+#endif
 
 #endif