diff options
| author | Solomon Peachy <pizza@shaftnet.org> | 2013-08-27 20:29:46 -0400 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2013-09-09 14:40:53 -0400 |
| commit | aec8e88c947b7017e2b4bbcb68a4bfc4a1f8ad35 (patch) | |
| tree | 584e2a99402483e16d6145bdf1d29416a1a0abce /drivers/net/wireless/cw1200/hwio.c | |
| parent | e7d33bb5ea82922e6ddcfc6b28a630b1a4ced071 (diff) | |
cw1200: Don't perform SPI transfers in interrupt context
When we get an interrupt from the hardware, the first thing the driver does
is tell the device to mask off the interrupt line. Unfortunately this
involves a SPI transaction in interrupt context. Some (most?) SPI
controllers perform the transfer asynchronously and try to sleep.
This is bad, and triggers a BUG().
So, work around this by using adding a hwbus hook for the cw1200 driver
core to call. The cw1200_spi driver translates this into
irq_disable()/irq_enable() calls instead, which can safely be called in
interrupt context.
Apparently the platforms I used to develop the cw1200_spi driver used
synchronous spi_sync() implementations, which is why this didn't surface
until now.
Many thanks to Dave Sizeburns for the inital bug report and his services
as a tester.
Signed-off-by: Solomon Peachy <pizza@shaftnet.org>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'drivers/net/wireless/cw1200/hwio.c')
| -rw-r--r-- | drivers/net/wireless/cw1200/hwio.c | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/drivers/net/wireless/cw1200/hwio.c b/drivers/net/wireless/cw1200/hwio.c index ff230b7aeedd..41bd7615ccaa 100644 --- a/drivers/net/wireless/cw1200/hwio.c +++ b/drivers/net/wireless/cw1200/hwio.c @@ -273,6 +273,21 @@ int __cw1200_irq_enable(struct cw1200_common *priv, int enable) u16 val16; int ret; + /* We need to do this hack because the SPI layer can sleep on I/O + and the general path involves I/O to the device in interrupt + context. + + However, the initial enable call needs to go to the hardware. + + We don't worry about shutdown because we do a full reset which + clears the interrupt enabled bits. + */ + if (priv->hwbus_ops->irq_enable) { + ret = priv->hwbus_ops->irq_enable(priv->hwbus_priv, enable); + if (ret || enable < 2) + return ret; + } + if (HIF_8601_SILICON == priv->hw_type) { ret = __cw1200_reg_read_32(priv, ST90TDS_CONFIG_REG_ID, &val32); if (ret < 0) { |