cmd: bootvx: Pass E820 information to an x86 VxWorks kernel

E820 is critical to the kernel as it provides system memory map
information. Pass it to an x86 VxWorks kernel.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Tom Rini <trini@konsulko.com>
Tested-by: Jian Luo <jian.luo4@boschrexroth.de>

common/cmd_elf.c

@@ -18,6 +18,9 @@
 #include <elf.h>
 #include <net.h>
 #include <vxworks.h>
+#ifdef CONFIG_X86
+#include <asm/e820.h>
+#endif
 
 /*
  * A very simple elf loader, assumes the image is valid, returns the
@@ -214,6 +217,10 @@ int do_bootvx(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	char *tmp; /* Temporary char pointer */
 	char build_buf[128]; /* Buffer for building the bootline */
 	int ptr = 0;
+#ifdef CONFIG_X86
+	struct e820info *info;
+	struct e820entry *data;
+#endif
 
 	/*
 	 * Check the loadaddr variable.
@@ -336,6 +343,29 @@ int do_bootvx(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 		       (char *)bootaddr);
 	}
 
+#ifdef CONFIG_X86
+	/*
+	 * Since E820 information is critical to the kernel, if we don't
+	 * specify these in the environments, use a default one.
+	 */
+	tmp = getenv("e820data");
+	if (tmp)
+		data = (struct e820entry *)simple_strtoul(tmp, NULL, 16);
+	else
+		data = (struct e820entry *)VXWORKS_E820_DATA_ADDR;
+	tmp = getenv("e820info");
+	if (tmp)
+		info = (struct e820info *)simple_strtoul(tmp, NULL, 16);
+	else
+		info = (struct e820info *)VXWORKS_E820_INFO_ADDR;
+
+	memset(info, 0, sizeof(struct e820info));
+	info->sign = E820_SIGNATURE;
+	info->entries = install_e820_map(E820MAX, data);
+	info->addr = (info->entries - 1) * sizeof(struct e820entry) +
+		     VXWORKS_E820_DATA_ADDR;
+#endif
+
 	/*
 	 * If the data at the load address is an elf image, then
 	 * treat it like an elf image. Otherwise, assume that it is a

include/vxworks.h

@@ -8,6 +8,35 @@
 #ifndef _VXWORKS_H_
 #define _VXWORKS_H_
 
+/*
+ * VxWorks x86 E820 related stuff
+ *
+ * VxWorks on x86 gets E820 information from pre-defined address @
+ * 0x4a00 and 0x4000. At 0x4a00 it's an information table defined
+ * by VxWorks and the actual E820 table entries starts from 0x4000.
+ * As defined by the BIOS E820 spec, the maximum number of E820 table
+ * entries is 128 and each entry occupies 20 bytes, so it's 128 * 20
+ * = 2560 (0xa00) bytes in total. That's where VxWorks stores some
+ * information that is retrieved from the BIOS E820 call and saved
+ * later for sanity test during the kernel boot-up.
+ */
+#define VXWORKS_E820_DATA_ADDR	0x4000
+#define VXWORKS_E820_INFO_ADDR	0x4a00
+
+/* E820 info signatiure "SMAP" - System MAP */
+#define E820_SIGNATURE	0x534d4150
+
+struct e820info {
+	u32 sign;	/* "SMAP" signature */
+	u32 x0;		/* don't care, used by VxWorks */
+	u32 x1;		/* don't care, used by VxWorks */
+	u32 x2;		/* don't care, used by VxWorks */
+	u32 addr;	/* last e820 table entry addr */
+	u32 x3;		/* don't care, used by VxWorks */
+	u32 entries;	/* e820 table entry count */
+	u32 error;	/* must be zero */
+};
+
 int do_bootvx(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]);
 void boot_prep_vxworks(bootm_headers_t *images);
 void boot_jump_vxworks(bootm_headers_t *images);