Sorry, made a bit of a mess with the last e-mail :(. Trying again :)
This patch fix's the possible priority inversion that vitaly pointed out and allows the driver to
be built as a module.
David, please can you test this patch. Can you also submit a patch which adds the module author,
description and license please, thanks. Kconfig | 2 +-
spi.c | 23 ++++++++++++++++++-----
2 files changed, 19 insertions(+), 6 deletions(-)
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diff -uprN spi-org/Kconfig spi/Kconfig
--- spi-org/Kconfig 2005-12-05 19:49:52.000000000 +0000
+++ spi/Kconfig 2005-12-05 18:38:06.000000000 +0000
@@ -22,7 +22,7 @@ config SPI_ARCH_HAS_SLAVE
default y if ARCH_PXA
config SPI
- bool "SPI support"
+ tristate "SPI support"
depends on SPI_ARCH_HAS_MASTER || SPI_ARCH_HAS_SLAVE
help
The "Serial Peripheral Interface" is a low level synchronous
diff -uprN spi-org/spi.c spi/spi.c
--- spi-org/spi.c 2005-12-05 19:49:52.000000000 +0000
+++ spi/spi.c 2005-12-05 19:06:05.000000000 +0000
@@ -232,6 +232,8 @@ EXPORT_SYMBOL_GPL(spi_new_device);
* The board info passed can safely be __initdata ... but be careful of
* any embedded pointers (platform_data, etc), they're copied as-is.
*/
+
+#ifdef CONFIG_SPI
int __init
spi_register_board_info(struct spi_board_info const *info, unsigned n)
{
@@ -249,6 +251,7 @@ spi_register_board_info(struct spi_board
return 0;
}
EXPORT_SYMBOL_GPL(spi_register_board_info);
+#endif
/* FIXME someone should add support for a __setup("spi", ...) that
* creates board info from kernel command lines
@@ -505,6 +508,7 @@ int spi_write_then_read(struct spi_devic
int status;
struct spi_message message;
struct spi_transfer x[2];
+ u8 *local_buf;
/* Use preallocated DMA-safe buffer. We can't avoid copying here,
* (as a pure convenience thing), but we can keep heap costs
@@ -513,14 +517,19 @@ int spi_write_then_read(struct spi_devic
if ((n_tx + n_rx) > SPI_BUFSIZ)
return -EINVAL;
- down(&lock);
+ if (down_trylock(&lock))
+ /* Someone else is using the main buffer, kalloc a new one */
+ local_buf = kmalloc(SPI_BUFSIZ, GFP_ATOMIC);
+ else
+ local_buf = buf;
+
memset(x, 0, sizeof x);
- memcpy(buf, txbuf, n_tx);
- x[0].tx_buf = buf;
+ memcpy(local_buf, txbuf, n_tx);
+ x[0].tx_buf = local_buf;
x[0].len = n_tx;
- x[1].rx_buf = buf + n_tx;
+ x[1].rx_buf = local_buf + n_tx;
x[1].len = n_rx;
/* do the i/o */
@@ -532,7 +541,11 @@ int spi_write_then_read(struct spi_devic
status = message.status;
}
- up(&lock);
+ if (x[0].tx_buf == buf)
+ up(&lock);
+ else
+ kfree(local_buf);
+
return status;
}
EXPORT_SYMBOL_GPL(spi_write_then_read);
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