[flashrom] [PATCH] SPI bitbanging core fixups

[Carl-Daniel Hailfinger]

Change the SPI bitbanging core to fix a few subtle bugs (which had no
effect so far) and to make integration of the RayeR SPIPGM and Nvidia
MCP6x/MCP7x SPI patches easier.

A big thank you to Johannes Sjölund for testing the code as part of the
Nvidia MCP6x/MCP7x SPI bitbanging patch.

This is the common part of the RayeR/Nvidia SPI patch. Tested on a dozen
machines, works fine.

Signed-off-by: Carl-Daniel Hailfinger

Index: flashrom-bitbang_spi_fixup/flash.h
===================================================================
--- flashrom-bitbang_spi_fixup/flash.h	(Revision 1082)
+++ flashrom-bitbang_spi_fixup/flash.h	(Arbeitskopie)
@@ -133,8 +133,6 @@

extern const int bitbang_spi_master_count;

-extern enum bitbang_spi_master bitbang_spi_master;
-
 struct bitbang_spi_master_entry {
    void (*set_cs) (int val);
    void (*set_sck) (int val);
@@ -535,7 +533,7 @@
 /* bitbang_spi.c */
 extern int bitbang_spi_half_period;
 extern const struct bitbang_spi_master_entry bitbang_spi_master_table[];
-int bitbang_spi_init(void);
+int bitbang_spi_init(enum bitbang_spi_master master);
 int bitbang_spi_send_command(unsigned int writecnt, unsigned int readcnt, const unsigned char *writearr, unsigned char *readarr);
 int bitbang_spi_read(struct flashchip *flash, uint8_t *buf, int start, int len);
 int bitbang_spi_write_256(struct flashchip *flash, uint8_t *buf, int start, int len);
Index: flashrom-bitbang_spi_fixup/hwaccess.h
===================================================================
--- flashrom-bitbang_spi_fixup/hwaccess.h	(Revision 1082)
+++ flashrom-bitbang_spi_fixup/hwaccess.h	(Arbeitskopie)
@@ -176,6 +176,10 @@
 #define __DARWIN__
 #endif

+/* Clarification about OUTB/OUTW/OUTL argument order:
+ * OUT[BWL](val, port)
+ */
+
 #if defined(__FreeBSD__) || defined(__DragonFly__)
   #include <machine/cpufunc.h>
   #define off64_t off_t
Index: flashrom-bitbang_spi_fixup/bitbang_spi.c
===================================================================
--- flashrom-bitbang_spi_fixup/bitbang_spi.c	(Revision 1082)
+++ flashrom-bitbang_spi_fixup/bitbang_spi.c	(Arbeitskopie)
@@ -26,8 +26,8 @@
 #include "chipdrivers.h"
 #include "spi.h"

-/* Length of half a clock period in usecs */
-int bitbang_spi_half_period = 0;
+/* Length of half a clock period in usecs. Default to 1 (500 kHz). */
+int bitbang_spi_half_period = 1;

enum bitbang_spi_master bitbang_spi_master = BITBANG_SPI_INVALID;

@@ -37,6 +37,7 @@

const int bitbang_spi_master_count = ARRAY_SIZE(bitbang_spi_master_table);

+/* Note that CS# is active low, so val=0 means the chip is active. */
 void bitbang_spi_set_cs(int val)
 {
    bitbang_spi_master_table[bitbang_spi_master].set_cs(val);
@@ -57,10 +58,18 @@
    return bitbang_spi_master_table[bitbang_spi_master].get_miso();
 }

-int bitbang_spi_init(void)
+int bitbang_spi_init(enum bitbang_spi_master master)
 {
+	bitbang_spi_master = master;
+
+	if (bitbang_spi_master == BITBANG_SPI_INVALID) {
+		msg_perr("Invalid bitbang SPI master. \n"
+			 "Please report a bug at [e-mail]\n");
+		return 1;
+	}
    bitbang_spi_set_cs(1);
    bitbang_spi_set_sck(0);
+	bitbang_spi_set_mosi(0);
    buses_supported = CHIP_BUSTYPE_SPI;
    return 0;
 }
@@ -87,6 +96,7 @@
 {
    static unsigned char *bufout = NULL;
    static unsigned char *bufin = NULL;
+	unsigned char *tmp;
    static int oldbufsize = 0;
    int bufsize;
    int i;
@@ -98,20 +108,34 @@
    bufsize = max(writecnt + readcnt, 260);
    /* Never shrink. realloc() calls are expensive. */
    if (bufsize > oldbufsize) {
-		bufout = realloc(bufout, bufsize);
-		if (!bufout) {
+		tmp = realloc(bufout, bufsize);
+		if (!tmp) {
    		msg_perr("Out of memory!\n");
+			if (bufout)
+				free(bufout);
+			bufout = NULL;
    		if (bufin)
    			free(bufin);
+			bufin = NULL;
+			oldbufsize = 0;
    		exit(1);
-		}
-		bufin = realloc(bufout, bufsize);
-		if (!bufin) {
+		} else
+			bufout = tmp;
+
+		tmp = realloc(bufin, bufsize);
+		if (!tmp) {
    		msg_perr("Out of memory!\n");
+			if (bufin)
+				free(bufin);
+			bufin = NULL;
    		if (bufout)
    			free(bufout);
+			bufout = NULL;
+			oldbufsize = 0;
    		exit(1);
-		}
+		} else
+			bufin = tmp;
+
    	oldbufsize = bufsize;
    }
    	
@@ -135,8 +159,13 @@

int bitbang_spi_read(struct flashchip *flash, uint8_t *buf, int start, int len)
 {
-	/* Maximum read length is unlimited, use 64k bytes. */
-	return spi_read_chunked(flash, buf, start, len, 64 * 1024);
+	/* Maximum read length is unlimited in theory.
+	 * The current implementation can handle reads of up to 65536 bytes.
+	 * Please note that you need two buffers of 2n+4 bytes each for a read
+	 * of n bytes, resulting in a total memory requirement of 4n+8 bytes.
+	 * To conserve memory, read in chunks of 256 bytes.
+	 */
+	return spi_read_chunked(flash, buf, start, len, 256);
 }

int bitbang_spi_write_256(struct flashchip *flash, uint8_t *buf, int start, int len)