Edward O'Callaghan has uploaded this change for review.

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Add support for continuous SPI reads

Forward port the original patch from Duncan Laurie <dlaurie@chromium.org>
in commit 06ffd5263892061c5ebf46e52b7878786cf2cece so that it fits for
upstream consumption.

This patch adds support for "unbounded reads" which are for continous
reads to a SPI flash chip instead of reading in page size blocks.

This speeds up the flash process over FTDI by quite a bit, testing
the read of a 16MB part it goes from 2m11s to 0m15s.

Change-Id: I804545aeb1b827ffdd41b21024fd618475e8263a
Signed-off-by: Edward O'Callaghan <quasisec@chromium.org>
---
M chipdrivers.h
M flash.h
M spi.c
M spi25.c
4 files changed, 40 insertions(+), 1 deletion(-)

git pull ssh://review.coreboot.org:29418/flashrom refs/changes/84/34584/1

diff --git a/chipdrivers.h b/chipdrivers.h
index e380878..77e1943 100644
--- a/chipdrivers.h
+++ b/chipdrivers.h
@@ -55,6 +55,7 @@
 int spi_chip_write_1(struct flashctx *flash, const uint8_t *buf, unsigned int start, unsigned int len);
 int spi_nbyte_read(struct flashctx *flash, unsigned int addr, uint8_t *bytes, unsigned int len);
 int spi_read_chunked(struct flashctx *flash, uint8_t *buf, unsigned int start, unsigned int len, unsigned int chunksize);
+int spi_read_unbound(struct flashchip *flash, uint8_t *buf, unsigned int start, unsigned int len, unsigned int chunksize);
 int spi_write_chunked(struct flashctx *flash, const uint8_t *buf, unsigned int start, unsigned int len, unsigned int chunksize);
 int spi_enter_4ba(struct flashctx *flash);
 int spi_exit_4ba(struct flashctx *flash);
diff --git a/flash.h b/flash.h
index b60a980..981f88b 100644
--- a/flash.h
+++ b/flash.h
@@ -143,6 +143,8 @@
 
 #define ERASED_VALUE(flash)	(((flash)->chip->feature_bits & FEATURE_ERASED_ZERO) ? 0x00 : 0xff)
 
+#define FEATURE_UNBOUND_READ   (1 << 19)
+
 enum test_state {
 	OK = 0,
 	NT = 1,	/* Not tested */
diff --git a/spi.c b/spi.c
index 489baf3..23f4cfe 100644
--- a/spi.c
+++ b/spi.c
@@ -75,13 +75,18 @@
 		     unsigned int len)
 {
 	unsigned int max_data = flash->mst->spi.max_data_read;
+       int rc;
 	if (max_data == MAX_DATA_UNSPECIFIED) {
 		msg_perr("%s called, but SPI read chunk size not defined "
 			 "on this hardware. Please report a bug at "
 			 "flashrom@flashrom.org\n", __func__);
 		return 1;
 	}
-	return spi_read_chunked(flash, buf, start, len, max_data);
+       if (flash->feature_bits & FEATURE_UNBOUND_READ)
+               rc = spi_read_unbound(flash, buf, start, len, max_data);
+       else
+               rc = spi_read_chunked(flash, buf, start, len, max_data);
+       return rc;
 }
 
 int default_spi_write_256(struct flashctx *flash, const uint8_t *buf, unsigned int start, unsigned int len)
diff --git a/spi25.c b/spi25.c
index 2a1d492..3327110 100644
--- a/spi25.c
+++ b/spi25.c
@@ -659,6 +659,37 @@
 }
 
 /*
+ * Read a part of the flash chip.
+ * Ignore pages and read the data continuously, the only bound is the chunksize.
+ */
+int spi_read_unbound(struct flashctx *flash, uint8_t *buf, unsigned int start, unsigned int len, unsigned int chunksize)
+{
+	int rc = 0;
+	unsigned int i;
+
+	for (i = start; i < (start + len); i += chunksize) {
+		int chunk_status = 0;
+		unsigned int toread = min(chunksize, start + len - i);
+
+		chunk_status = spi_nbyte_read(flash, i, buf + (i - start), toread);
+		if (chunk_status) {
+			if (ignore_error(chunk_status)) {
+				/* fill this chunk with 0xff bytes and
+				   let caller know about the error */
+				memset(buf + (i - start), 0xff, toread);
+				rc = chunk_status;
+				continue;
+			} else {
+				rc = chunk_status;
+				break;
+			}
+		}
+	}
+
+	return rc;
+}
+
+/*
  * Write a part of the flash chip.
  * FIXME: Use the chunk code from Michael Karcher instead.
  * Each page is written separately in chunks with a maximum size of chunksize.

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