[PATCH] add some EFI device smarts

[PATCH] add some EFI device smarts

[Bjorn Helgaas]

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.

Re: [PATCH] add some EFI device smarts

[Matt Domsch]

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On Tue, Apr 20, 2004 at 04:00:26PM -0600, Bjorn Helgaas wrote:
> (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.)

Matt T. had done the work to move it under drivers/efi, though now
that there's a drivers/firmware, that's more appropraite.  It also
converted it to use sysfs instead of proc.  There was a bug in
efivars_exit() where it was removing stuff (which could sleep) while
holding a spinlock which wasn't good, but that was about the only
issue anyone had with it.

> +		/* 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;

I've never had a clear understanding of this.  It's not really UTF8
(else straight ASCII text could be used), but more like UCS2.  (Yeah,
I'm sure I named it wrong myself too in the rest of the file...)  

> +
> +		if (strcmp(name_utf8, name))
> +			continue;

This ignores the fact that someone could create a variable with the
same name but a different vendor GUID, and it would return the first
one found.  Unfortunately, you need to request both pieces
specifically - 

+int
+efi_get_variable(char *name, efi_variable_t *guid, unsigned char *data, unsigned long *size)

and do a guidcmp() on them as well as the strcmp() on the name.

> +int __init
> +efi_uart_console_only(void)

So to be useful, efivars can't be build modular anymore, right?  Then
Kconfig needs to change as well.  It's module_init(), is that early
enough to be used?  Where is efi_uart_console_only() called from?
It's not in this patch.

> +typedef struct {
> +	u8 type;
> +	u8 sub_type;
> +	u16 length;
> +} efi_generic_dev_path_t;

No typedefs, just struct efi_generic_dev_path, and
__attribute__((packed)) please just to be safe.


Thanks,
Matt

-- 
Matt Domsch
Sr. Software Engineer, Lead Engineer
Dell Linux Solutions linux.dell.com & www.dell.com/linux
Linux on Dell mailing lists @ http://lists.us.dell.com

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RE: [PATCH] add some EFI device smarts

[Tolentino, Matthew E]

> On Tue, Apr 20, 2004 at 04:00:26PM -0600, Bjorn Helgaas wrote:
> > (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.)
> 
> Matt T. had done the work to move it under drivers/efi, though now
> that there's a drivers/firmware, that's more appropraite.  It also
> converted it to use sysfs instead of proc.  There was a bug in
> efivars_exit() where it was removing stuff (which could sleep) while
> holding a spinlock which wasn't good, but that was about the only
> issue anyone had with it.

Indeed.  I fixed that and one other small issue Greg pointed out
a while ago.  I'll resend updated efivars driver patches in a separate
mail shortly.   

> +int
> +efi_get_variable(char *name, efi_variable_t *guid, unsigned 
> char *data, unsigned long *size)
> 
> and do a guidcmp() on them as well as the strcmp() on the name.
> 
> > +int __init
> > +efi_uart_console_only(void)
> 
> So to be useful, efivars can't be build modular anymore, right?  Then
> Kconfig needs to change as well.  It's module_init(), is that early
> enough to be used?  Where is efi_uart_console_only() called from?
> It's not in this patch.

This part isn't clear to me.  It looks like you are including a 
duplicate efi_get_variable function in efi.c in order to have 
access to EFI variable services (and perform the checks) very early 
before console initialization and/or efivars is available ... is 
that correct?    

thanks,
matt

Re: [PATCH] add some EFI device smarts

[Bjorn Helgaas]

On Tuesday 20 April 2004 5:50 pm, Matt Domsch wrote:
> Matt T. had done the work to move it under drivers/efi, though now
> that there's a drivers/firmware, that's more appropraite.

Sounds good.  I'll let Matt T. worry about that for now.

> > +		/* 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;
> 
> I've never had a clear understanding of this.  It's not really UTF8
> (else straight ASCII text could be used), but more like UCS2.

I don't understand Unicode either.  Maybe the attached is a little
closer?  The EFI spec (1.10, table 2-2) says strings are stored in
UTF-16, and I think that UTF-16 is the same as ASCII for
(0 < c <= 0x7f).

I also stuck in the GUID stuff and removed the typedef (I prefer
the plain structs myself, but was just following the existing style ;-)).

Oh, BTW, my changes are in efi.c, not efivars.c, so no Kconfig
or modular build implications. 

I'll try to post the patch that calls efi_uart_console_only() today.
I just didn't want these EFI changes to get buried in the rest of
that.  Thanks a lot for the feedback!

Bjorn

=== 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	Wed Apr 21 06:31:33 2004
@@ -747,6 +747,72 @@
 	return 0;
 }
 
+int
+efi_get_variable(char *name, efi_guid_t guid, unsigned char *data,
+	unsigned long *size, u32 *attributes)
+{
+	efi_status_t status;
+	efi_guid_t vendor_guid;
+	efi_char16_t name_utf16[128];
+	char name_ascii[ARRAY_SIZE(name_utf16) + 1];
+	unsigned long name_size;
+	int i;
+
+	memset(name_utf16, 0, sizeof(name_utf16));
+	for (;;) {
+		name_size = sizeof(name_utf16);
+		status = efi.get_next_variable(&name_size, name_utf16,
+			&vendor_guid);
+		if (status != EFI_SUCCESS)
+			return -EINVAL;
+
+		/* Convert UTF-16 to ASCII */
+		for (i = 0; i < (name_size/sizeof(name_utf16[0])); i++)
+			name_ascii[i] = name_utf16[i] & 0x7f;
+		name_ascii[i] = 0;
+
+		if (strcmp(name_ascii, name) || efi_guidcmp(guid, vendor_guid))
+			continue;
+
+		status = efi.get_variable(name_utf16, &guid, attributes,
+			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);
+	struct efi_generic_dev_path *hdr, *end_addr;
+	int uart = 0;
+
+	if (efi_get_variable("ConOut", EFI_GLOBAL_VARIABLE_GUID, data, &size, NULL) < 0)
+		return 0;
+
+	hdr = (struct efi_generic_dev_path *) data;
+	end_addr = (struct efi_generic_dev_path *) ((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 = (struct efi_generic_dev_path *) ((u8 *) hdr + hdr->length);
+	}
+	return 0;	/* malformed path (no end) */
+}
+
 static void __exit
 efivars_exit (void)
 {
=== arch/ia64/kernel/efivars.c 1.15 vs edited ==--- 1.15/arch/ia64/kernel/efivars.c	Tue Feb 10 19:51:27 2004
+++ edited/arch/ia64/kernel/efivars.c	Wed Apr 21 06:41:25 2004
@@ -191,10 +191,9 @@
 	       variable_name_size);
 	memcpy(&(new_efivar->var.VendorGuid), vendor_guid, sizeof(efi_guid_t));
 
-	/* Convert Unicode to normal chars (assume top bits are 0),
-	   ala UTF-8 */
+	/* Convert UTF-16 to ASCII (assume top bits are 0) */
 	for (i=0; i< (int) (variable_name_size / sizeof(efi_char16_t)); i++) {
-		short_name[i] = variable_name[i] & 0xFF;
+		short_name[i] = variable_name[i] & 0x7F;
 	}
 
 	/* This is ugly, but necessary to separate one vendor's
=== 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	Wed Apr 21 06:25:22 2004
@@ -212,6 +212,9 @@
 #define UGA_IO_PROTOCOL_GUID \
     EFI_GUID(  0x61a4d49e, 0x6f68, 0x4f1b, 0xb9, 0x22, 0xa8, 0x6e, 0xed, 0xb, 0x7, 0xa2 )
 
+#define EFI_GLOBAL_VARIABLE_GUID \
+    EFI_GUID(  0x8be4df61, 0x93ca, 0x11d2, 0xaa, 0x0d, 0x00, 0xe0, 0x98, 0x03, 0x2b, 0x8c )
+
 typedef struct {
 	efi_guid_t guid;
 	unsigned long table;
@@ -294,6 +297,8 @@
 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, efi_guid_t guid, unsigned char *data, unsigned long *size, u32 *attributes);
+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 +327,49 @@
 #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
+
+struct efi_generic_dev_path {
+	u8 type;
+	u8 sub_type;
+	u16 length;
+} __attribute ((packed));
 
 /*
  * efi_dir is allocated in arch/ia64/kernel/efi.c.

Re: [PATCH] add some EFI device smarts

[Matthew Wilcox]

On Wed, Apr 21, 2004 at 06:59:22AM -0600, Bjorn Helgaas wrote:
> > > +		/* 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;
> > 
> > I've never had a clear understanding of this.  It's not really UTF8
> > (else straight ASCII text could be used), but more like UCS2.
> 
> I don't understand Unicode either.  Maybe the attached is a little
> closer?  The EFI spec (1.10, table 2-2) says strings are stored in
> UTF-16, and I think that UTF-16 is the same as ASCII for
> (0 < c <= 0x7f).

Ah, I know this one ...

UTF-16 is like UCS-2 except that it has escapes to let you use past the
first plane of Unicode.  That is, by and large it's 2-bytes long, but
sometimes it can be 4 or more bytes long.  How to convert?  Let's see ...

	for (i = 0, j = 0; i < (name_size/sizeof(name_unicode[0])); i++) {
		unsigned int rune = name_unicode[i];
		if (0xD7FF < rune && rune < 0xE000) {
			rune = (rune & 0x7ff) << 10;
			rune |= name_unicode[++i] & 0x3ff;
		}
		if (rune < 0x80) {
			name_utf8[j++] = rune;
		} else if (rune < 0x800) {
			name_utf8[j++] = 0xc0 | (rune >> 6);
			name_utf8[j++] = 0x80 | (rune & 0x3f);
		} else if (rune < 0x10000) {
			name_utf8[j++] = 0xe0 | (rune >> 12);
			name_utf8[j++] = 0x80 | ((rune >> 6) & 0x3f);
			name_utf8[j++] = 0x80 | (rune & 0x3f);
		} else {
			name_utf8[j++] = 0xf0 | (rune >> 18);
			name_utf8[j++] = 0x80 | ((rune >> 12) & 0x3f);
			name_utf8[j++] = 0x80 | ((rune >> 6) & 0x3f);
			name_utf8[j++] = 0x80 | (rune & 0x3f);
		}
	}

ftp://ftp.rfc-editor.org/in-notes/rfc2279.txt
ftp://ftp.rfc-editor.org/in-notes/rfc2781.txt

Haven't even tried to compile it ...

-- 
"Next the statesmen will invent cheap lies, putting the blame upon 
the nation that is attacked, and every man will be glad of those
conscience-soothing falsities, and will diligently study them, and refuse
to examine any refutations of them; and thus he will by and by convince 
himself that the war is just, and will thank God for the better sleep 
he enjoys after this process of grotesque self-deception." -- Mark Twain