Patchwork [U-Boot,3/5] x86: Add CBMEM console driver for coreboot

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Submitter Simon Glass
Date Oct. 13, 2012, 4:48 a.m.
Message ID <1350103729-15913-3-git-send-email-sjg@chromium.org>
Download mbox | patch
Permalink /patch/191276/
State Accepted, archived
Delegated to: Simon Glass
Headers show

Comments

Simon Glass - Oct. 13, 2012, 4:48 a.m.
From: Vadim Bendebury <vbendeb@chromium.org>

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>
---
 common/stdio.c               |    4 ++-
 drivers/misc/Makefile        |    1 +
 drivers/misc/cbmem_console.c |   67 ++++++++++++++++++++++++++++++++++++++++++
 include/stdio_dev.h          |    3 ++
 4 files changed, 74 insertions(+), 1 deletions(-)
 create mode 100644 drivers/misc/cbmem_console.c

Patch

diff --git a/common/stdio.c b/common/stdio.c
index 605ff3f..9f48e5f 100644
--- 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 271463c..a77db3d 100644
--- 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_FSL_LAW) += fsl_law.o
 COBJS-$(CONFIG_GPIO_LED) += gpio_led.o
 COBJS-$(CONFIG_FSL_MC9SDZ60) += mc9sdz60.o
diff --git a/drivers/misc/cbmem_console.c b/drivers/misc/cbmem_console.c
new file mode 100644
index 0000000..80a84fd
--- /dev/null
+++ b/drivers/misc/cbmem_console.c
@@ -0,0 +1,67 @@ 
+/*
+ * Copyright (C) 2011 The ChromiumOS Authors.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * 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, write to the Free Software
+ * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA, 02110-1301 USA
+ */
+
+#include <common.h>
+
+#ifndef CONFIG_SYS_COREBOOT
+#error This driver requires coreboot
+#endif
+
+#include <asm/arch/sysinfo.h>
+
+struct cbmem_console {
+	u32 buffer_size;
+	u32 buffer_cursor;
+	u8  buffer_body[0];
+}  __attribute__ ((__packed__));
+
+static struct cbmem_console *cbmem_console_p;
+
+void cbmemc_putc(char data)
+{
+	int cursor;
+
+	cursor = cbmem_console_p->buffer_cursor++;
+	if (cursor < cbmem_console_p->buffer_size)
+		cbmem_console_p->buffer_body[cursor] = data;
+}
+
+void cbmemc_puts(const char *str)
+{
+	char c;
+
+	while ((c = *str++) != 0)
+		cbmemc_putc(c);
+}
+
+int cbmemc_init(void)
+{
+	int rc;
+	struct stdio_dev cons_dev;
+	cbmem_console_p = lib_sysinfo.cbmem_cons;
+
+	memset(&cons_dev, 0, sizeof(cons_dev));
+
+	strcpy(cons_dev.name, "cbmem");
+	cons_dev.flags = DEV_FLAGS_OUTPUT; /* Output only */
+	cons_dev.putc  = cbmemc_putc;
+	cons_dev.puts  = cbmemc_puts;
+
+	rc = stdio_register(&cons_dev);
+
+	return (rc == 0) ? 1 : rc;
+}
diff --git a/include/stdio_dev.h b/include/stdio_dev.h
index 23e0ee1..932d093 100644
--- 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