[U-Boot] [PATCH 2/3] bootvx: Prepare e820 related stuff from the given kernel memory base address

[Bin Meng]

At present two environment variables 'e820data'/'e820info' are required
to boot a VxWorks x86 kernel, but this is superfluous. The offset of
these two tables are actually at a fixed offset from the kernel memory
base address and we can provide the kernel memory base address to U-Boot
via only one variable 'vx_phys_mem_base'.

Note as it name indicates, the physical address should be provided.

Signed-off-by: Bin Meng <bmeng.cn at gmail.com>
---

 cmd/elf.c          | 21 ++++++++-------------
 doc/README.vxworks | 18 +++++++-----------
 include/vxworks.h  | 12 +++++++++---
 3 files changed, 24 insertions(+), 27 deletions(-)

diff --git a/cmd/elf.c b/cmd/elf.c
index f874073..eec9f14 100644
--- a/cmd/elf.c
+++ b/cmd/elf.c
@@ -333,26 +333,21 @@ int do_bootvx(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
 	}
 
 #ifdef CONFIG_X86
+	ulong base;
+
 	/*
-	 * Since E820 information is critical to the kernel, if we don't
-	 * specify these in the environments, use a default one.
+	 * Get VxWorks's physical memory base address from environment,
+	 * if we don't specify it in the environment, use a default one.
 	 */
-	tmp = env_get("e820data");
-	if (tmp)
-		data = (struct e820entry *)simple_strtoul(tmp, NULL, 16);
-	else
-		data = (struct e820entry *)VXWORKS_E820_DATA_ADDR;
-	tmp = env_get("e820info");
-	if (tmp)
-		info = (struct e820info *)simple_strtoul(tmp, NULL, 16);
-	else
-		info = (struct e820info *)VXWORKS_E820_INFO_ADDR;
+	base = env_get_hex("vx_phys_mem_base", VXWORKS_PHYS_MEM_BASE);
+	data = (struct e820entry *)(base + E820_DATA_OFFSET);
+	info = (struct e820info *)(base + E820_INFO_OFFSET);
 
 	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;
+		     E820_DATA_OFFSET;
 #endif
 
 	/*
diff --git a/doc/README.vxworks b/doc/README.vxworks
index eb1f458..b95a516 100644
--- a/doc/README.vxworks
+++ b/doc/README.vxworks
@@ -67,17 +67,13 @@ look like VxWorks hangs somewhere as nothing outputs on the serial console.
 
 x86-specific information
 ------------------------
-Before loading an x86 kernel, two additional environment variables need to be
-provided. They are "e820data" and "e820info", which represent the address of
-E820 table and E820 information (defined by VxWorks) in system memory.
-
-Check VxWorks kernel configuration to look for BIOS_E820_DATA_START and
-BIOS_E820_INFO_START, and assign their values to "e820data" and "e820info"
-accordingly. If neither of these two are supplied, U-Boot assumes a default
-location at 0x4000 for "e820data" and 0x4a00 for "e820info". Typical values
-for "e820data" and "e820info" are 0x104000 and 0x104a00. But there is one
-exception on Intel Galileo, where "e820data" and "e820info" should be left
-unset, which assume the default location for VxWorks.
+Before loading an x86 kernel, one additional environment variable need to be
+provided. This is "vx_phys_mem_base", which represent the physical memory
+base address of VxWorks.
+
+Check VxWorks kernel configuration to look for LOCAL_MEM_LOCAL_ADRS. For
+VxWorks 7, this is normally a virtual address and you need find out its
+corresponding physical address and assign its value to "vx_phys_mem_base".
 
 For boards on which ACPI is not supported by U-Boot yet, VxWorks kernel must
 be configured to use MP table and virtual wire interrupt mode. This requires
diff --git a/include/vxworks.h b/include/vxworks.h
index f69b008..f600dfa 100644
--- a/include/vxworks.h
+++ b/include/vxworks.h
@@ -9,9 +9,15 @@
 #define _VXWORKS_H_
 
 /*
+ * Physical address of memory base for VxWorks x86
+ * This is LOCAL_MEM_LOCAL_ADRS in the VxWorks kernel configuration.
+ */
+#define VXWORKS_PHYS_MEM_BASE	0x100000
+
+/*
  * VxWorks x86 E820 related stuff
  *
- * VxWorks on x86 gets E820 information from pre-defined address @
+ * VxWorks on x86 gets E820 information from pre-defined offset @
  * 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
@@ -20,8 +26,8 @@
  * 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
+#define E820_DATA_OFFSET	0x4000
+#define E820_INFO_OFFSET	0x4a00
 
 /* E820 info signatiure "SMAP" - System MAP */
 #define E820_SIGNATURE	0x534d4150
-- 
2.7.4