| Message ID | 1377649787-2817-1-git-send-email-pizza@shaftnet.org (mailing list archive) |
|---|---|
| State | Not Applicable, archived |
| Headers | show |
On Tue, Aug 27, 2013 at 08:29:46PM -0400, Solomon Peachy wrote: > 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(). Did this patch series get dropped? I saw that the followup series of minor cleanups were merged into wireless-next, but not these. Since they didn't make it into 3.11, I intend to submit them to -stable, but I need to make sure they at least make it into -next. Thanks, - Solomon
On Tue, Sep 03, 2013 at 07:58:57AM -0400, Solomon Peachy wrote: > On Tue, Aug 27, 2013 at 08:29:46PM -0400, Solomon Peachy wrote: > > 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(). > > Did this patch series get dropped? I saw that the followup series > of minor cleanups were merged into wireless-next, but not these. > > Since they didn't make it into 3.11, I intend to submit them to -stable, > but I need to make sure they at least make it into -next. I'll be sending them for 3.12 soon...
On Mon, Sep 09, 2013 at 02:33:50PM -0400, John W. Linville wrote: > > Since they didn't make it into 3.11, I intend to submit them to -stable, > > but I need to make sure they at least make it into -next. > > I'll be sending them for 3.12 soon... Can you please revert this commit? (aec8e88c947b7017e2b4bbcb68a4bfc4a1f8ad35) It ends up creating horrible interrupt losses. I'll have a much simpler replacement posted shortly. - Solomon
diff --git a/drivers/net/wireless/cw1200/cw1200_spi.c b/drivers/net/wireless/cw1200/cw1200_spi.c index d063760..c31580b 100644 --- a/drivers/net/wireless/cw1200/cw1200_spi.c +++ b/drivers/net/wireless/cw1200/cw1200_spi.c @@ -41,6 +41,7 @@ struct hwbus_priv { const struct cw1200_platform_data_spi *pdata; spinlock_t lock; /* Serialize all bus operations */ int claimed; + int irq_disabled; }; #define SDIO_TO_SPI_ADDR(addr) ((addr & 0x1f)>>2) @@ -230,6 +231,8 @@ static irqreturn_t cw1200_spi_irq_handler(int irq, void *dev_id) struct hwbus_priv *self = dev_id; if (self->core) { + disable_irq_nosync(self->func->irq); + self->irq_disabled = 1; cw1200_irq_handler(self->core); return IRQ_HANDLED; } else { @@ -263,13 +266,22 @@ exit: static int cw1200_spi_irq_unsubscribe(struct hwbus_priv *self) { - int ret = 0; - pr_debug("SW IRQ unsubscribe\n"); disable_irq_wake(self->func->irq); free_irq(self->func->irq, self); - return ret; + return 0; +} + +static int cw1200_spi_irq_enable(struct hwbus_priv *self, int enable) +{ + /* Disables are handled by the interrupt handler */ + if (enable && self->irq_disabled) { + enable_irq(self->func->irq); + self->irq_disabled = 0; + } + + return 0; } static int cw1200_spi_off(const struct cw1200_platform_data_spi *pdata) @@ -349,6 +361,7 @@ static struct hwbus_ops cw1200_spi_hwbus_ops = { .unlock = cw1200_spi_unlock, .align_size = cw1200_spi_align_size, .power_mgmt = cw1200_spi_pm, + .irq_enable = cw1200_spi_irq_enable, }; /* Probe Function to be called by SPI stack when device is discovered */ diff --git a/drivers/net/wireless/cw1200/fwio.c b/drivers/net/wireless/cw1200/fwio.c index acdff0f..0b2061b 100644 --- a/drivers/net/wireless/cw1200/fwio.c +++ b/drivers/net/wireless/cw1200/fwio.c @@ -485,7 +485,7 @@ int cw1200_load_firmware(struct cw1200_common *priv) /* Enable interrupt signalling */ priv->hwbus_ops->lock(priv->hwbus_priv); - ret = __cw1200_irq_enable(priv, 1); + ret = __cw1200_irq_enable(priv, 2); priv->hwbus_ops->unlock(priv->hwbus_priv); if (ret < 0) goto unsubscribe; diff --git a/drivers/net/wireless/cw1200/hwbus.h b/drivers/net/wireless/cw1200/hwbus.h index 8b2fc83..51dfb3a 100644 --- a/drivers/net/wireless/cw1200/hwbus.h +++ b/drivers/net/wireless/cw1200/hwbus.h @@ -28,6 +28,7 @@ struct hwbus_ops { void (*unlock)(struct hwbus_priv *self); size_t (*align_size)(struct hwbus_priv *self, size_t size); int (*power_mgmt)(struct hwbus_priv *self, bool suspend); + int (*irq_enable)(struct hwbus_priv *self, int enable); }; #endif /* CW1200_HWBUS_H */ diff --git a/drivers/net/wireless/cw1200/hwio.c b/drivers/net/wireless/cw1200/hwio.c index ff230b7..41bd761 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) {
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> --- Please consider this for 3.11-rc; without this patch many SPI users will immediately trigger a BUG(). drivers/net/wireless/cw1200/cw1200_spi.c | 19 ++++++++++++++++--- drivers/net/wireless/cw1200/fwio.c | 2 +- drivers/net/wireless/cw1200/hwbus.h | 1 + drivers/net/wireless/cw1200/hwio.c | 15 +++++++++++++++ 4 files changed, 33 insertions(+), 4 deletions(-)