spi/spi_mpc8xxx: fix potential memory corruption.

tx_dma/rx_dma are already set to a dummy buffer when no
tx/rx buffer and t->tx_dma/t->rx_dma does not contain a dma
address, but NULL.
This may lead to corruption of kernel memory. Fix this by
leaving tx_dma/rx_dma alone.

Do not INIT_TX_RX while controller is enabled, this is bad according
to the MPC8321 manual.

Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Acked-by: Anton Vorontsov <cbouatmailru@gmail.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
This commit is contained in:
Joakim Tjernlund 2010-05-22 02:18:02 -06:00 committed by Grant Likely
parent e40152ee1e
commit f9218c2a60

View File

@ -241,7 +241,6 @@ static void mpc8xxx_spi_change_mode(struct spi_device *spi)
/* Turn off SPI unit prior changing mode */
mpc8xxx_spi_write_reg(mode, cs->hw_mode & ~SPMODE_ENABLE);
mpc8xxx_spi_write_reg(mode, cs->hw_mode);
/* When in CPM mode, we need to reinit tx and rx. */
if (mspi->flags & SPI_CPM_MODE) {
@ -258,7 +257,7 @@ static void mpc8xxx_spi_change_mode(struct spi_device *spi)
}
}
}
mpc8xxx_spi_write_reg(mode, cs->hw_mode);
local_irq_restore(flags);
}
@ -438,7 +437,7 @@ static int mpc8xxx_spi_cpm_bufs(struct mpc8xxx_spi *mspi,
dev_err(dev, "unable to map tx dma\n");
return -ENOMEM;
}
} else {
} else if (t->tx_buf) {
mspi->tx_dma = t->tx_dma;
}
@ -449,7 +448,7 @@ static int mpc8xxx_spi_cpm_bufs(struct mpc8xxx_spi *mspi,
dev_err(dev, "unable to map rx dma\n");
goto err_rx_dma;
}
} else {
} else if (t->rx_buf) {
mspi->rx_dma = t->rx_dma;
}