[flashrom] [PATCH] Add Linux SPI support

[Sven Schnelle]

Uwe Hermann <uwe at hermann-uwe.de> writes:

> On Wed, Mar 02, 2011 at 11:56:43PM +0100, Carl-Daniel Hailfinger wrote:
>> > Signed-off-by: Sven Schnelle <svens at stackframe.org>
>
> Thanks, committed as r1427 with a few changes as proposed below, and
> with more changes due to forward-porting to current flashrom trunk.

Thanks! I must admit that i actually forgot about that patch (but using
it for about half a year now ;-)

>> > +int linux_spi_send_command(unsigned int writecnt, unsigned int readcnt,
>> > +		const unsigned char *txbuf, unsigned char *rxbuf)
>> > +{
>> > +	struct spi_ioc_transfer msg[2] = {
>> > +		{ .tx_buf = (unsigned long)txbuf, .len = writecnt },
>> > +		{ .rx_buf = (unsigned long)rxbuf, .len = readcnt }
>> >   
>> 
>> Really unsigned long casts for txbuf and rxbuf?
>
> Required it seems, as otherwise:
>
>   linux_spi.c:111:4: error: initialization makes integer from pointer without a cast [-Werror]
>   linux_spi.c:111:4: error: (near initialization for ‘msg[0].tx_buf’) [-Werror]
>   etc.
>
> This is due to .tx_buf/.rx_buf being defined as __u64 in linux/spi/spidev.h:
>
>   struct spi_ioc_transfer {
>           __u64           tx_buf;
>           __u64           rx_buf;
>   	...
>   }
>
> I changed "unsigned long" to "uint64_t", though.

That breaks compilation on 32bit for me (AVR32 is 32bit):

linux_spi.c:110: warning: cast from pointer to integer of different size
linux_spi.c:114: warning: cast from pointer to integer of different size

I've changed the code to:

Index: linux_spi.c
===================================================================
--- linux_spi.c	(revision 1427)
+++ linux_spi.c	(working copy)
@@ -107,11 +107,11 @@
 {
 	struct spi_ioc_transfer msg[2] = {
 		{
-			.tx_buf = (uint64_t)txbuf,
+			.tx_buf = (uint64_t)(ptrdiff_t)txbuf,
 			.len = writecnt,
 		},
 		{
-			.rx_buf = (uint64_t)rxbuf,
+			.rx_buf = (uint64_t)(ptrdiff_t)rxbuf,
 			.len = readcnt,
 		},
 	};

> Sven, can you please check if trunk works for you, and/or fix it if I
> broke stuff? Also, do you plan to work on addressing the other TODOs?
> I guess I have some board where I can test this driver too, but it will
> take a while to setup etc.

I've did a short test with the patch above, and flashrom works fine on
linux-2.6.38. Will respond to the other TODOs in a seperate Mail.

Sven.