Added easier to read chip_select/reset functions.

Just calling a gpio function with two numbers was not very self
explanatory. The functions now refer to the actual indended action, chip
(de)select for flash, reset and chip (de)select for sram. Reading the
code and understanding what steps are taken should be easier now.

1 files changed, 60 insertions, 26 deletions

diff --git a/iceprog/iceprog.c b/iceprog/iceprog.c
index 5a29733..c0a1406 100644
--- a/iceprog/iceprog.c
+++ b/iceprog/iceprog.c
@@ -287,14 +287,48 @@ static int get_cdone()
 // FLASH function implementations
 // ---------------------------------------------------------
 
+// the FPGA reset is released so also FLASH chip select should be deasserted
+static void flash_release_reset()
+{
+	set_gpio(1, 1);
+}
+
+// FLASH chip select assert/deassert
+// should only happen while FPGA reset is asserted
+static void flash_chip_select(bool assert)
+{
+	if(assert)
+		set_gpio(0, 0);
+	else
+		set_gpio(1, 0);
+}
+
+// SRAM reset is pretty much the same as flash_chip_select(true)
+// For ease of code reading we use this function instead
+static void sram_reset()
+{
+	// Asserting chip select and reset lines
+	set_gpio(0, 0);
+}
+
+// When accessing FPGA SRAM the reset should be released
+static void sram_chip_select(bool assert)
+{
+	if(assert)
+		set_gpio(0, 1);
+	else
+		set_gpio(1, 1);
+}
+
 static void flash_read_id()
 {
 	// fprintf(stderr, "read flash ID..\n");
 
 	uint8_t data[21] = { FC_JEDECID };
-	set_gpio(0, 0);
+
+	flash_chip_select(true);
 	xfer_spi(data, 21);
-	set_gpio(1, 0);
+	flash_chip_select(false);
 
 	fprintf(stderr, "flash ID:");
 	for (int i = 1; i < 21; i++)
@@ -305,17 +339,17 @@ static void flash_read_id()
 static void flash_power_up()
 {
 	uint8_t data[1] = { FC_RPD };
-	set_gpio(0, 0);
+	flash_chip_select(true);
 	xfer_spi(data, 1);
-	set_gpio(1, 0);
+	flash_chip_select(false);
 }
 
 static void flash_power_down()
 {
 	uint8_t data[1] = { FC_PD };
-	set_gpio(0, 0);
+	flash_chip_select(true);
 	xfer_spi(data, 1);
-	set_gpio(1, 0);
+	flash_chip_select(false);
 }
 
 static void flash_write_enable()
@@ -324,9 +358,9 @@ static void flash_write_enable()
 		fprintf(stderr, "write enable..\n");
 
 	uint8_t data[1] = { FC_WE };
-	set_gpio(0, 0);
+	flash_chip_select(true);
 	xfer_spi(data, 1);
-	set_gpio(1, 0);
+	flash_chip_select(false);
 }
 
 static void flash_bulk_erase()
@@ -334,9 +368,9 @@ static void flash_bulk_erase()
 	fprintf(stderr, "bulk erase..\n");
 
 	uint8_t data[1] = { FC_CE };
-	set_gpio(0, 0);
+	flash_chip_select(true);
 	xfer_spi(data, 1);
-	set_gpio(1, 0);
+	flash_chip_select(false);
 }
 
 static void flash_64kB_sector_erase(int addr)
@@ -345,9 +379,9 @@ static void flash_64kB_sector_erase(int addr)
 
 	uint8_t command[4] = { FC_BE64, (uint8_t)(addr >> 16), (uint8_t)(addr >> 8), (uint8_t)addr };
 
-	set_gpio(0, 0);
+	flash_chip_select(true);
 	send_spi(command, 4);
-	set_gpio(1, 0);
+	flash_chip_select(false);
 }
 
 static void flash_prog(int addr, uint8_t *data, int n)
@@ -357,10 +391,10 @@ static void flash_prog(int addr, uint8_t *data, int n)
 
 	uint8_t command[4] = { FC_PP, (uint8_t)(addr >> 16), (uint8_t)(addr >> 8), (uint8_t)addr };
 
-	set_gpio(0, 0);
+	flash_chip_select(true);
 	send_spi(command, 4);
 	send_spi(data, n);
-	set_gpio(1, 0);
+	flash_chip_select(false);
 
 	if (verbose)
 		for (int i = 0; i < n; i++)
@@ -374,11 +408,11 @@ static void flash_read(int addr, uint8_t *data, int n)
 
 	uint8_t command[4] = { FC_RD, (uint8_t)(addr >> 16), (uint8_t)(addr >> 8), (uint8_t)addr };
 
-	set_gpio(0, 0);
+	flash_chip_select(true);
 	send_spi(command, 4);
 	memset(data, 0, n);
 	xfer_spi(data, n);
-	set_gpio(1, 0);
+	flash_chip_select(false);
 
 	if (verbose)
 		for (int i = 0; i < n; i++)
@@ -418,18 +452,18 @@ static void flash_disable_protection()
 
 	//WRSR 0x00
 	uint8_t data[2] = { 0x01, 0x00 };
-	set_gpio(0, 0);
+	flash_chip_select(true);
 	xfer_spi(data, 2);
-	set_gpio(1, 0);
+	flash_chip_select(false);
 	
 	flash_wait();
 	
 	//RDSR
 	data[0] = 0x5;
 
-	set_gpio(0, 0);\
+	flash_chip_select(true);
 	xfer_spi(data, 2);
-	set_gpio(1, 0);
+	flash_chip_select(false);
 
 	if(data[1] != 0x00)
 		fprintf(stderr, "failed to disable protection, SR now equal to 0x%02x (expected 0x00)\n", data[1]);
@@ -833,7 +867,7 @@ int main(int argc, char **argv)
 
 	fprintf(stderr, "cdone: %s\n", get_cdone() ? "high" : "low");
 
-	set_gpio(1, 1);
+	flash_release_reset();
 	usleep(100000);
 
 
@@ -841,7 +875,7 @@ int main(int argc, char **argv)
 	{
 		fprintf(stderr, "reset..\n");
 
-		set_gpio(1, 0);
+		flash_chip_select(false);
 		usleep(250000);
 
 		fprintf(stderr, "cdone: %s\n", get_cdone() ? "high" : "low");
@@ -852,7 +886,7 @@ int main(int argc, char **argv)
 
 		flash_power_down();
 
-		set_gpio(1, 1);
+		flash_release_reset();
 		usleep(250000);
 
 		fprintf(stderr, "cdone: %s\n", get_cdone() ? "high" : "low");
@@ -865,10 +899,10 @@ int main(int argc, char **argv)
 
 		fprintf(stderr, "reset..\n");
 
-		set_gpio(0, 0);
+		sram_reset();
 		usleep(100);
 
-		set_gpio(0, 1);
+		sram_chip_select(true);
 		usleep(2000);
 
 		fprintf(stderr, "cdone: %s\n", get_cdone() ? "high" : "low");
@@ -908,7 +942,7 @@ int main(int argc, char **argv)
 
 		fprintf(stderr, "reset..\n");
 
-		set_gpio(1, 0);
+		flash_chip_select(false);
 		usleep(250000);
 
 		fprintf(stderr, "cdone: %s\n", get_cdone() ? "high" : "low");