serprog: Add support for setting the SPI frequency

Introduce a new opcode (0x14) that sends the requested frequency as a 32b
long value in Hertz to the programmer and receives the frequency eventually
chosen by the programmer. The user can specify this with the programmer
parameter "spispeed" (named after the similar parameter for the buspirate)
including an optional suffix of 'M' or 'k' for specifying megahertz or kilohertz
respectively (lowercase suffixes are also accepted).

Thanks to Idwer and Uwe (and maybe others) for their feedback especially
regarding the unit of frequency to use.

Corresponding to flashrom svn r1571.

Signed-off-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>
Acked-by: Stefan Tauner <stefan.tauner@alumni.tuwien.ac.at>

1 files changed, 47 insertions, 0 deletions

diff --git a/serprog.c b/serprog.c
index 3529127..e418c3e 100644
--- a/serprog.c
+++ b/serprog.c
@@ -69,6 +69,7 @@ static int serprog_shutdown(void *data);
 #define S_CMD_Q_RDNMAXLEN	0x11	/* Query read-n maximum length			*/
 #define S_CMD_S_BUSTYPE		0x12	/* Set used bustype(s).				*/
 #define S_CMD_O_SPIOP		0x13	/* Perform SPI operation.			*/
+#define S_CMD_S_SPI_FREQ	0x14	/* Set SPI clock frequency			*/
 
 static uint16_t sp_device_serbuf_size = 16;
 static uint16_t sp_device_opbuf_size = 300;
@@ -482,6 +483,7 @@ int serprog_init(void)
 	/* Check for the minimum operational set of commands. */
 	if (serprog_buses_supported & BUS_SPI) {
 		uint8_t bt = BUS_SPI;
+		char *spispeed;
 		if (sp_check_commandavail(S_CMD_O_SPIOP) == 0) {
 			msg_perr("Error: SPI operation not supported while the "
 				 "bustype is SPI\n");
@@ -513,6 +515,51 @@ int serprog_init(void)
 			spi_programmer_serprog.max_data_read = v;
 			msg_pdbg(MSGHEADER "Maximum read-n length is %d\n", v);
 		}
+		spispeed = extract_programmer_param("spispeed");
+		if (spispeed && strlen(spispeed)) {
+			uint32_t f_spi_req, f_spi;
+			uint8_t buf[4];
+			char *f_spi_suffix;
+
+			errno = 0;
+			f_spi_req = strtol(spispeed, &f_spi_suffix, 0);
+			if (errno != 0 || spispeed == f_spi_suffix) {
+				msg_perr("Error: Could not convert 'spispeed'.\n");
+				return 1;
+			}
+			if (strlen(f_spi_suffix) == 1) {
+				if (!strcasecmp(f_spi_suffix, "M"))
+					f_spi_req *= 1000000;
+				else if (!strcasecmp(f_spi_suffix, "k"))
+					f_spi_req *= 1000;
+				else {
+					msg_perr("Error: Garbage following 'spispeed' value.\n");
+					return 1;
+				}
+			} else if (strlen(f_spi_suffix) > 1) {
+				msg_perr("Error: Garbage following 'spispeed' value.\n");
+				return 1;
+			}
+
+			buf[0] = (f_spi_req >> (0 * 8)) & 0xFF;
+			buf[1] = (f_spi_req >> (1 * 8)) & 0xFF;
+			buf[2] = (f_spi_req >> (2 * 8)) & 0xFF;
+			buf[3] = (f_spi_req >> (3 * 8)) & 0xFF;
+
+			if (sp_check_commandavail(S_CMD_S_SPI_FREQ) == 0)
+				msg_perr(MSGHEADER "Warning: Setting the SPI clock rate is not supported!\n");
+			else if (sp_docommand(S_CMD_S_SPI_FREQ, 4, buf, 4, buf)
+				 == 0) {
+				f_spi = buf[0];
+				f_spi |= buf[1] << (1 * 8);
+				f_spi |= buf[2] << (2 * 8);
+				f_spi |= buf[3] << (3 * 8);
+				msg_pdbg(MSGHEADER "Requested to set SPI clock frequency to %u Hz. "
+					 "It was actually set to %u Hz\n", f_spi_req, f_spi);
+			} else
+				msg_pdbg(MSGHEADER "Setting SPI clock rate to %u Hz failed!\n", f_spi_req);
+		}
+		free(spispeed);
 		bt = serprog_buses_supported;
 		if (sp_docommand(S_CMD_S_BUSTYPE, 1, &bt, 0, NULL))
 			return 1;