OMAP: Support for Android RAM console

Android's RAMCONSOLE framework is handy framework which allows
saving the kernel printk messages to a buffer in RAM, so that
after a kernel panic they can be viewed in the next kernel
invocation, by accessing /proc/last_kmsg.

This obviously needs DDR to be in selfrefresh mode. Board files
which have relevant support need to enable CONFIG_OMAP_RAM_CONSOLE
and call omap_ram_console_init with relevant parameters for this
to function.

Change-Id: I2dd5ad55a0a3af5a5dcb9a9b8a797e1371af39bc
Signed-off-by: Huzefa Kankroliwala <huzefank@ti.com>
Signed-off-by: Akash Choudhari <akashc@ti.com>
Signed-off-by: Ameya Palande <ameya.palande@ti.com>
Signed-off-by: Nishanth Menon <nm@ti.com>

4 files changed, 132 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
index 5d83504..eac405e 100755
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -394,6 +394,16 @@ config OMAP_REBOOT_REASON
 	depends on ARCH_OMAP4
 	bool
 
+config OMAP_RAM_CONSOLE
+        bool "Enable OMAP support for Android RAM console"
+        depends on ANDROID_RAM_CONSOLE
+        help
+          Select this option to enable Android RAM console support on OMAP.
+          This allows saving the kernel printk messages to a buffer in RAM, so
+          that after a kernel panic they can be viewed in the next kernel
+          invocation, by accessing /proc/last_kmsg
+          NOTE: Board file needs to invoke relevant api to enable the support
+
 endmenu
 
 endif
diff --git a/arch/arm/mach-omap2/Makefile b/arch/arm/mach-omap2/Makefile
index 359c22f..61799c9 100644
--- a/arch/arm/mach-omap2/Makefile
+++ b/arch/arm/mach-omap2/Makefile
@@ -316,3 +316,5 @@ obj-$(CONFIG_OMAP_FIQ_DEBUGGER)		+= omap_fiq_debugger.o
 ifeq ($(CONFIG_OMAP_REBOOT_REASON),y)
 obj-$(CONFIG_ARCH_OMAP4)		+= omap4-reboot-reason.o
 endif
+
+obj-$(CONFIG_OMAP_RAM_CONSOLE)		+= omap_ram_console.o
diff --git a/arch/arm/mach-omap2/omap_ram_console.c b/arch/arm/mach-omap2/omap_ram_console.c
new file mode 100644
index 0000000..cf84c64
--- /dev/null
+++ b/arch/arm/mach-omap2/omap_ram_console.c
@@ -0,0 +1,87 @@
+/*
+ * OMAP ram console support
+ *
+ * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
+ * Author: Huzefa Kankroliwala <huzefank@ti.com>
+ *
+ * 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 "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <linux/platform_device.h>
+#include <linux/platform_data/ram_console.h>
+#include <linux/memblock.h>
+#include <plat/cpu.h>
+#include "resetreason.h"
+#include "omap_ram_console.h"
+
+static struct resource ram_console_resources[] = {
+	{
+		.flags  = IORESOURCE_MEM,
+		.start  = OMAP_RAM_CONSOLE_START_DEFAULT,
+		.end    = OMAP_RAM_CONSOLE_START_DEFAULT +
+			  OMAP_RAM_CONSOLE_SIZE_DEFAULT - 1,
+	},
+};
+
+static struct ram_console_platform_data ram_console_pdata;
+
+static struct platform_device ram_console_device = {
+	.name		= "ram_console",
+	.id		= -1,
+	.num_resources	= ARRAY_SIZE(ram_console_resources),
+	.resource	= ram_console_resources,
+	.dev		= {
+	.platform_data	= &ram_console_pdata,
+	},
+};
+
+/**
+ * omap_ram_console_init() - setup the ram console device for OMAP
+ * @phy_addr:	physical address of the start of ram console buffer
+ * @size:	ram console buffer size
+ *
+ * Board files call this as part of the memory reservation routine
+ * Depending on the choice of memory geometry and desired size,
+ * provide appropriate parameters.
+ *
+ * IMPORTANT: board files need to ensure that the DDR configurations
+ * enable self refresh mode for this to function properly.
+ */
+
+int __init omap_ram_console_init(phys_addr_t phy_addr, size_t size)
+{
+	int ret;
+
+	/* Remove the ram console region from kernel's map */
+	ret = memblock_remove(phy_addr, size);
+	if (ret) {
+		pr_err("%s: unable to remove memory for ram console:"
+			"start=0x%08x, size=0x%08x, ret=%d\n",
+			__func__, (u32)phy_addr, (u32)size, ret);
+		return ret;
+	}
+
+	/* Update reset reason for platforms that have support for it */
+	if (cpu_is_omap44xx())
+		ram_console_pdata.bootinfo = omap4_get_resetreason();
+
+	ram_console_resources[0].start = phy_addr;
+	ram_console_resources[0].end = phy_addr + size - 1;
+
+	ret = platform_device_register(&ram_console_device);
+	if (ret) {
+		pr_err("%s: unable to register ram console device:"
+			"start=0x%08x, size=0x%08x, ret=%d\n",
+			__func__, (u32)phy_addr, (u32)size, ret);
+		memblock_add(phy_addr, size);
+	}
+
+	return ret;
+}
diff --git a/arch/arm/mach-omap2/omap_ram_console.h b/arch/arm/mach-omap2/omap_ram_console.h
new file mode 100644
index 0000000..edd75e8
--- /dev/null
+++ b/arch/arm/mach-omap2/omap_ram_console.h
@@ -0,0 +1,33 @@
+/*
+ * OMAP ram console support
+ *
+ * Copyright (C) 2011 Texas Instruments Incorporated - http://www.ti.com/
+ * Author: Huzefa Kankroliwala <huzefank@ti.com>
+ *
+ * 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 "as is" WITHOUT ANY WARRANTY of any
+ * kind, whether express or implied; without even the implied warranty
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __OMAP_RAM_CONSOLE_H
+#define __OMAP_RAM_CONSOLE_H
+
+/* Board files use the following if they are ok with 512M size defaults */
+#define OMAP_RAM_CONSOLE_START_DEFAULT	(PLAT_PHYS_OFFSET + SZ_512M)
+#define OMAP_RAM_CONSOLE_SIZE_DEFAULT	SZ_2M
+
+#ifdef CONFIG_OMAP_RAM_CONSOLE
+extern int omap_ram_console_init(phys_addr_t phy_addr, size_t size);
+#else
+static inline int omap_ram_console_init(phys_addr_t phy_addr, size_t size)
+{
+	return 0;
+}
+#endif /* CONFIG_OMAP_RAM_CONSOLE */
+
+#endif