[PATCH -v2.6.32] ibft: Finding IBFT ACPI table on UEFI

commit 935a9fee51c945b8942be2d7b4bae069167b4886 upstream.

Found one system with UEFI/iBFT, kernel does not detect the iBFT during
iscsi_ibft module loading.

So users will need to input iscsi info during RHEL 6.x installation.

We can add checking in ibft_init for acpi.

At that time ACPI iBFT already get permanent mapped with ioremap.

For legacy one, print the found address early.


Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 drivers/firmware/iscsi_ibft.c |   42 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

Index: linux-2.6/drivers/firmware/iscsi_ibft.c
===================================================================
--- linux-2.6.orig/drivers/firmware/iscsi_ibft.c
+++ linux-2.6/drivers/firmware/iscsi_ibft.c
@@ -926,6 +926,37 @@ static int __init ibft_register_attribut
 	return rc;
 }
 
+#ifdef CONFIG_ACPI
+static const struct {
+	char *sign;
+} ibft_signs[] = {
+	/*
+	 * One spec says "IBFT", the other says "iBFT". We have to check
+	 * for both.
+	 */
+	{ ACPI_SIG_IBFT },
+	{ "iBFT" },
+};
+
+static void __init acpi_find_ibft_region(void)
+{
+	int i;
+	struct acpi_table_header *table = NULL;
+
+	if (acpi_disabled)
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(ibft_signs) && !ibft_addr; i++) {
+		acpi_get_table(ibft_signs[i].sign, 0, &table);
+		ibft_addr = (struct acpi_table_ibft *)table;
+	}
+}
+#else
+static void __init acpi_find_ibft_region(void)
+{
+}
+#endif
+
 /*
  * ibft_init() - creates sysfs tree entries for the iBFT data.
  */
@@ -937,9 +968,16 @@ static int __init ibft_init(void)
 	if (!ibft_kset)
 		return -ENOMEM;
 
+	/*
+	   As on UEFI systems the setup_arch()/find_ibft_region()
+	   is called before ACPI tables are parsed and it only does
+	   legacy finding.
+	*/
+	if (!ibft_addr)
+		acpi_find_ibft_region();
+
 	if (ibft_addr) {
-		printk(KERN_INFO "iBFT detected at 0x%llx.\n",
-		       (u64)isa_virt_to_bus(ibft_addr));
+		pr_info("iBFT detected.\n");
 
 		rc = ibft_check_device();
 		if (rc)