[PATCH] add some EFI device smarts

Bjorn Helgaas
2004-04-20T22:00:26Z

This patch against current 2.6 BK adds efi_get_variable() and
efi_uart_console_only().

The first thing I want to use this for is smarter console detection.
In the absence of a "console=" argument, we currently always default
to a VGA console. But if the EFI ConOut variable includes only UART
devices, we ought to take advantage of that and use a serial console
instead.

This is based on previous work by Khalid Aziz and Alex Williamson.

(Like much of the EFI stuff, this really isn't ia64-specific. Maybe
it's time to move some of it under drivers/efi? If there's interest,
I can look at doing that.)

=== arch/ia64/kernel/efi.c 1.31 vs edited ==--- 1.31/arch/ia64/kernel/efi.c Mon Apr 12 04:21:11 2004
+++ edited/arch/ia64/kernel/efi.c Tue Apr 20 14:46:28 2004
@@ -747,6 +747,71 @@
return 0;
}

+int
+efi_get_variable(char *name, unsigned char *data, unsigned long *size)
+{
+ efi_status_t status;
+ efi_guid_t vendor_guid;
+ efi_char16_t name_unicode[128];
+ char name_utf8[ARRAY_SIZE(name_unicode) + 1];
+ unsigned long name_size;
+ int i;
+
+ memset(name_unicode, 0, sizeof(name_unicode));
+ for (;;) {
+ name_size = sizeof(name_unicode);
+ status = efi.get_next_variable(&name_size, name_unicode,
+ &vendor_guid);
+ if (status != EFI_SUCCESS)
+ return -EINVAL;
+
+ /* Convert Unicode to normal chars */
+ for (i = 0; i < (name_size/sizeof(name_unicode[0])); i++)
+ name_utf8[i] = name_unicode[i] & 0xff;
+ name_utf8[i] = 0;
+
+ if (strcmp(name_utf8, name))
+ continue;
+
+ status = efi.get_variable(name_unicode, &vendor_guid, NULL,
+ size, data);
+ if (status != EFI_SUCCESS)
+ return -EINVAL;
+
+ return 0;
+ }
+}
+
+int __init
+efi_uart_console_only(void)
+{
+ unsigned char data[1024];
+ unsigned long size = sizeof(data);
+ efi_generic_dev_path_t *hdr, *end_addr;
+ int uart = 0;
+
+ if (efi_get_variable("ConOut", data, &size) < 0)
+ return 0;
+
+ hdr = (efi_generic_dev_path_t *) data;
+ end_addr = (efi_generic_dev_path_t *) ((u8 *) data + size);
+ while (hdr < end_addr) {
+ if (hdr->type = EFI_DEV_MSG &&
+ hdr->sub_type = EFI_DEV_MSG_UART)
+ uart = 1;
+ else if (hdr->type = EFI_DEV_END_PATH ||
+ hdr->type = EFI_DEV_END_PATH2) {
+ if (!uart)
+ return 0;
+ if (hdr->sub_type = EFI_DEV_END_ENTIRE)
+ return 1;
+ uart = 0;
+ }
+ hdr = (efi_generic_dev_path_t *) ((u8 *) hdr + hdr->length);
+ }
+ return 0; /* malformed path (no end) */
+}
+
static void __exit
efivars_exit (void)
{
=== include/linux/efi.h 1.7 vs edited ==--- 1.7/include/linux/efi.h Tue Feb 3 22:29:14 2004
+++ edited/include/linux/efi.h Tue Apr 20 14:47:46 2004
@@ -294,6 +294,8 @@
extern u64 efi_get_iobase (void);
extern u32 efi_mem_type (unsigned long phys_addr);
extern u64 efi_mem_attributes (unsigned long phys_addr);
+extern int efi_get_variable (char *name, unsigned char *data, unsigned long *size);
+extern int __init efi_uart_console_only (void);
extern void efi_initialize_iomem_resources(struct resource *code_resource,
struct resource *data_resource);
extern efi_status_t phys_efi_get_time(efi_time_t *tm, efi_time_cap_t *tc);
@@ -322,6 +324,49 @@
#define EFI_VARIABLE_BOOTSERVICE_ACCESS 0x0000000000000002
#define EFI_VARIABLE_RUNTIME_ACCESS 0x0000000000000004

+/*
+ * EFI Device Path information
+ */
+#define EFI_DEV_HW 0x01
+#define EFI_DEV_PCI 1
+#define EFI_DEV_PCCARD 2
+#define EFI_DEV_MEM_MAPPED 3
+#define EFI_DEV_VENDOR 4
+#define EFI_DEV_CONTROLLER 5
+#define EFI_DEV_ACPI 0x02
+#define EFI_DEV_BASIC_ACPI 1
+#define EFI_DEV_EXPANDED_ACPI 2
+#define EFI_DEV_MSG 0x03
+#define EFI_DEV_MSG_ATAPI 1
+#define EFI_DEV_MSG_SCSI 2
+#define EFI_DEV_MSG_FC 3
+#define EFI_DEV_MSG_1394 4
+#define EFI_DEV_MSG_USB 5
+#define EFI_DEV_MSG_USB_CLASS 15
+#define EFI_DEV_MSG_I20 6
+#define EFI_DEV_MSG_MAC 11
+#define EFI_DEV_MSG_IPV4 12
+#define EFI_DEV_MSG_IPV6 13
+#define EFI_DEV_MSG_INFINIBAND 9
+#define EFI_DEV_MSG_UART 14
+#define EFI_DEV_MSG_VENDOR 10
+#define EFI_DEV_MEDIA 0x04
+#define EFI_DEV_MEDIA_HARD_DRIVE 1
+#define EFI_DEV_MEDIA_CDROM 2
+#define EFI_DEV_MEDIA_VENDOR 3
+#define EFI_DEV_MEDIA_FILE 4
+#define EFI_DEV_MEDIA_PROTOCOL 5
+#define EFI_DEV_BIOS_BOOT 0x05
+#define EFI_DEV_END_PATH 0x7F
+#define EFI_DEV_END_PATH2 0xFF
+#define EFI_DEV_END_INSTANCE 0x01
+#define EFI_DEV_END_ENTIRE 0xFF
+
+typedef struct {
+ u8 type;
+ u8 sub_type;
+ u16 length;
+} efi_generic_dev_path_t;

/*
* efi_dir is allocated in arch/ia64/kernel/efi.c.