Re: [flashrom] [PATCH] Add Linux SPI support

[Sven Schnelle]

Hi Uwe,

Uwe Hermann  writes:
> > > +int linux_spi_init(void)
> > > +{
> > > char *p, *endp, *dev;
> > > int speed = 0;
> >
> > int speed, but later you use strtoul which fills an unsigned long.
>
> Fixed in the attached patch.
> > >    dev = extract_programmer_param("dev");
> > >    if (!dev || !strlen(dev)) {
> >
> > strlen(dev) can happen if the user specified no device name:
> > -p linux_spi:dev=
> > Please handle that case separately (error message, abort).

How can that happen? The NULL pointer and zero length cases are handled
correctly. With the current trunk i get:

# ./flashrom -r test.bin -p linux_spi:dev=
flashrom v0.9.4-r1427 on Linux 2.6.38+ (avr32), built with GCC
4.2.4-atmel.1.1.3.avr32linux.1, big endian
flashrom is free software, get the source code at
http://www.flashrom.org

Calibrating delay loop... OK.
No SPI device given. Use flashrom -p linux_spi:dev=/dev/spidevX.Y
Error: Programmer initialization failed.

Which looks ok for me.
> > >            msg_perr("No spi device given. Use flashrom -p "
> > > 	 "linux_spi:dev=/dev/spidevX.Y\n");
> > >            return 1;
> > >    }   
> >
> > Maybe add a msg_dbg or msg_spew about the device name specified by the user.
>
> Done.
> > >    p = extract_programmer_param("speed");
> > >    if (p && strlen(p)) {
> >
> > Please handle the same problem for speed=
>
> Same question here :)
> > >    }   
> > > if ((fd = open(dev, O_RDWR)) == -1) {
> > > msg_perr("%s: failed to open %s: %s\n", __func__,
> > > 	 dev, strerror(errno));
> > > return 1;
> > > }
> > > if (speed > 0 && ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) == -1) {
> >
> > Are you 100% sure that this ioctl wants a signed int?
> > http://www.kernel.org/doc/Documentation/spi/spidev says something about
> > an u32.
>
> Fixed.
> > Not sure if Linux SPI masters use the right CPOL/CPHA and bit ordering
> > and bits per word by default, so setting SPI_IOC_WR_MODE and
> > SPI_IOC_WR_LSB_FIRST and SPI_IOC_WR_BITS_PER_WORD would probably be a
> > very good idea.

The spi_board_info structure in the board specific linux kernel code
specify the default values. Such a structure has to exist for every
single SPI device that sits on the Board, so we have correct default
values set in the Kernel. As a feature we might still make that
configurable later.

Signed-off-by: Sven Schnelle

Index: linux_spi.c
===================================================================
--- linux_spi.c	(revision 1427)
+++ linux_spi.c	(working copy)
@@ -54,7 +54,7 @@
 int linux_spi_init(void)
 {
    char *p, *endp, *dev;
-	int speed = 0;
+	uint32_t speed = 0;

dev = extract_programmer_param("dev");
    if (!dev || !strlen(dev)) {
@@ -65,31 +65,35 @@

p = extract_programmer_param("speed");
    if (p && strlen(p)) {
-		speed = strtoul(p, &endp, 10) * 1024;
+		speed = (uint32_t)strtoul(p, &endp, 10) * 1024;
    	if (p == endp) {
    		msg_perr("%s: invalid clock: %s kHz\n", __func__, p);
    		return 1;
    	}
    }

+	msg_pdbg("Using device %s\n", dev);
    if ((fd = open(dev, O_RDWR)) == -1) {
    	msg_perr("%s: failed to open %s: %s\n", __func__,
    		 dev, strerror(errno));
    	return 1;
    }

-	if (speed > 0 && ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) == -1) {
-		msg_perr("%s: failed to set speed %dHz: %s\n",
-			 __func__, speed, strerror(errno));
-		close(fd);
-		return 1;
-	}
+	if (speed > 0) {
+		if (ioctl(fd, SPI_IOC_WR_MAX_SPEED_HZ, &speed) == -1) {
+			msg_perr("%s: failed to set speed %dHz: %s\n",
+				 __func__, speed, strerror(errno));
+			close(fd);
+			return 1;
+		}

+		msg_pdbg("Using %d KHz clock\n", speed);
+        }
+
    if (register_shutdown(linux_spi_shutdown, NULL))
    	return 1;

register_spi_programmer(&spi_programmer_linux);
-
    return 0;
 }