[flashrom] [commit] r1170 - trunk

[repository service]

Author: hailfinger
Date: Wed Sep 15 02:13:02 2010
New Revision: 1170
URL: http://flashrom.org/trac/flashrom/changeset/1170

Log:
Honor ICH SPI address window for reads.

ICH SPI has the ability to restrict SPI read/write accesses to a given
address range. The low end of the range is configurable by the BIOS (and
by flashrom if the BIOS didn't lock down the flash interface), the high
end of the range is 0xffffff (2^24-1).
This patch checks for an address range restriction and uses the low end
of the allowed range as base for SPI reads. A similar workaround for
REMS/RES opcodes has been committed in r500.

This fixes read on the Intel D945GCLF mainboard where the stock BIOS
enforces a restricted address range.
Please note that writes need the same fix, but for architectural reasons
that fix will be merged once partial write is available.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>

Tested by David Hendricks on the Intel D945GCLF mainboard, results at
http://paste.flashrom.org/view.php?id=79

Acked-by: David Hendricks <dhendrix at google.com>

Modified:
   trunk/spi.c

Modified: trunk/spi.c
==============================================================================
--- trunk/spi.c	Wed Sep 15 02:03:53 2010	(r1169)
+++ trunk/spi.c	Wed Sep 15 02:13:02 2010	(r1170)
@@ -22,6 +22,7 @@
  * Contains the generic SPI framework
  */
 
+#include <string.h>
 #include "flash.h"
 #include "flashchips.h"
 #include "chipdrivers.h"
@@ -207,6 +208,7 @@
 
 int spi_chip_read(struct flashchip *flash, uint8_t *buf, int start, int len)
 {
+	int addrbase = 0;
 	if (!spi_programmer[spi_controller].read) {
 		msg_perr("%s called, but SPI read is unsupported on this "
 			 "hardware. Please report a bug at "
@@ -214,7 +216,26 @@
 		return 1;
 	}
 
-	return spi_programmer[spi_controller].read(flash, buf, start, len);
+	/* Check if the chip fits between lowest valid and highest possible
+	 * address. Highest possible address with the current SPI implementation
+	 * means 0xffffff, the highest unsigned 24bit number.
+	 */
+	addrbase = spi_get_valid_read_addr();
+	if (addrbase + flash->total_size * 1024 > (1 << 24)) {
+		msg_perr("Flash chip size exceeds the allowed access window. ");
+		msg_perr("Read will probably fail.\n");
+		/* Try to get the best alignment subject to constraints. */
+		addrbase = (1 << 24) - flash->total_size * 1024;
+	}
+	/* Check if alignment is native (at least the largest power of two which
+	 * is a factor of the mapped size of the chip).
+	 */
+	if (ffs(flash->total_size * 1024) > (ffs(addrbase) ? : 33)) {
+		msg_perr("Flash chip is not aligned natively in the allowed "
+			 "access window.\n");
+		msg_perr("Read will probably return garbage.\n");
+	}
+	return spi_programmer[spi_controller].read(flash, buf, addrbase + start, len);
 }
 
 /*