Hello Jan,
On Tue, Aug 28, 2007 at 05:17:07PM +0200, Jan Andersson wrote:
> When the spi_mpc83xx driver receives a tx_buf pointer which is NULL, it
> only writes one zero filled word to the transmit register. If the driver
> expects to receive more than one word it will wait forever for a second
> receive interrupt.
Confirmed here, mpc8323e using spidev_test with tx_buf == NULL.
> With this patch the controller will shift out zeroes
> until all bytes have been transferred. Applies to 2.6.23-rc4.
Ditto, patch seem to fix issue.
> This patch has not been tested with a MPC83xx device.
>
> Signed-off-by: Jan Andersson <[EMAIL PROTECTED]>
Tested-by: Anton Vorontsov <[EMAIL PROTECTED]>
> --
> I discovered this while working with a port of the mpc83xx driver from
> 2.6.21.1. It looks like the issue remains in 2.6.23-rc4. When performing a
> read from a M25P80 device the driver waits forever for a receive (Not
> Empty) interrupt that never occurs since the transmit register is not
> written when the first NE IRQ is handled. Please test or comment.
>
> I do not own a MPC83xx device and can not test this with the original
> hardware.
> --- linux-2.6/drivers/spi/spi_mpc83xx.orig 2007-08-28 16:01:59.000000000
> +0200
> +++ linux-2.6/drivers/spi/spi_mpc83xx.c 2007-08-28 16:04:35.000000000
> +0200
> @@ -384,11 +384,8 @@ irqreturn_t mpc83xx_spi_irq(s32 irq, voi
>
> mpc83xx_spi->count -= 1;
> if (mpc83xx_spi->count) {
> - if (mpc83xx_spi->tx) {
> - u32 word = mpc83xx_spi->get_tx(mpc83xx_spi);
> - mpc83xx_spi_write_reg(&mpc83xx_spi->base->transmit,
> - word);
> - }
> + u32 word = mpc83xx_spi->get_tx(mpc83xx_spi);
> + mpc83xx_spi_write_reg(&mpc83xx_spi->base->transmit, word);
> } else {
> complete(&mpc83xx_spi->done);
> }
Thanks,
--
Anton Vorontsov
email: [EMAIL PROTECTED]
backup email: [EMAIL PROTECTED]
irc://irc.freenode.net/bd2
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