| /openbmc/linux/drivers/net/ethernet/sfc/ |
| H A D | nic.c | d8291187 Fri Oct 05 17:35:41 CDT 2012 Ben Hutchings <bhutchings@solarflare.com> sfc: Rework IRQ enable/disable
There are many problems with the current efx_stop_interrupts() and
efx_start_interrupts():
1. On Siena, it is unsafe to disable the master IRQ enable bit
(DRV_INT_EN_KER) while any IRQ sources are enabled.
2. On EF10 there is no master IRQ enable bit, so we cannot expect to
defer IRQs without tearing down event queues. (Though I don't think
we will need to keep any event queues around while the device is down,
as we do for VFDI on Siena.)
3. synchronize_irq() only waits for a running IRQ handler to finish,
not for any propagation through IRQ controllers. Therefore an IRQ may
still be received and handled after efx_stop_interrupts() returns.
IRQ handlers can then race with channel reallocation.
To fix this:
a. Introduce a software IRQ enable flag. So long as this is clear,
IRQ handlers will only acknowledge IRQs and not touch the channel
structures.
b. Define a new struct efx_msi_context as the context for MSIs. This
is never reallocated and is sufficient to find the software enable
flag and the channel structure. It also includes the channel/IRQ
name, which was previously separated out as it must also not be
reallocated.
c. Split efx_{start,stop}_interrupts() into
efx_{,soft_}_{enable,disable}_interrupts(). The 'soft' functions
don't touch the hardware master enable flag (if it exists) and don't
reinitialise or tear down channels with the keep_eventq flag set.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
d8291187 Fri Oct 05 17:35:41 CDT 2012 Ben Hutchings <bhutchings@solarflare.com> sfc: Rework IRQ enable/disable
There are many problems with the current efx_stop_interrupts() and
efx_start_interrupts():
1. On Siena, it is unsafe to disable the master IRQ enable bit
(DRV_INT_EN_KER) while any IRQ sources are enabled.
2. On EF10 there is no master IRQ enable bit, so we cannot expect to
defer IRQs without tearing down event queues. (Though I don't think
we will need to keep any event queues around while the device is down,
as we do for VFDI on Siena.)
3. synchronize_irq() only waits for a running IRQ handler to finish,
not for any propagation through IRQ controllers. Therefore an IRQ may
still be received and handled after efx_stop_interrupts() returns.
IRQ handlers can then race with channel reallocation.
To fix this:
a. Introduce a software IRQ enable flag. So long as this is clear,
IRQ handlers will only acknowledge IRQs and not touch the channel
structures.
b. Define a new struct efx_msi_context as the context for MSIs. This
is never reallocated and is sufficient to find the software enable
flag and the channel structure. It also includes the channel/IRQ
name, which was previously separated out as it must also not be
reallocated.
c. Split efx_{start,stop}_interrupts() into
efx_{,soft_}_{enable,disable}_interrupts(). The 'soft' functions
don't touch the hardware master enable flag (if it exists) and don't
reinitialise or tear down channels with the keep_eventq flag set.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
|
| H A D | net_driver.h | d8291187 Fri Oct 05 17:35:41 CDT 2012 Ben Hutchings <bhutchings@solarflare.com> sfc: Rework IRQ enable/disable
There are many problems with the current efx_stop_interrupts() and
efx_start_interrupts():
1. On Siena, it is unsafe to disable the master IRQ enable bit
(DRV_INT_EN_KER) while any IRQ sources are enabled.
2. On EF10 there is no master IRQ enable bit, so we cannot expect to
defer IRQs without tearing down event queues. (Though I don't think
we will need to keep any event queues around while the device is down,
as we do for VFDI on Siena.)
3. synchronize_irq() only waits for a running IRQ handler to finish,
not for any propagation through IRQ controllers. Therefore an IRQ may
still be received and handled after efx_stop_interrupts() returns.
IRQ handlers can then race with channel reallocation.
To fix this:
a. Introduce a software IRQ enable flag. So long as this is clear,
IRQ handlers will only acknowledge IRQs and not touch the channel
structures.
b. Define a new struct efx_msi_context as the context for MSIs. This
is never reallocated and is sufficient to find the software enable
flag and the channel structure. It also includes the channel/IRQ
name, which was previously separated out as it must also not be
reallocated.
c. Split efx_{start,stop}_interrupts() into
efx_{,soft_}_{enable,disable}_interrupts(). The 'soft' functions
don't touch the hardware master enable flag (if it exists) and don't
reinitialise or tear down channels with the keep_eventq flag set.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
d8291187 Fri Oct 05 17:35:41 CDT 2012 Ben Hutchings <bhutchings@solarflare.com> sfc: Rework IRQ enable/disable
There are many problems with the current efx_stop_interrupts() and
efx_start_interrupts():
1. On Siena, it is unsafe to disable the master IRQ enable bit
(DRV_INT_EN_KER) while any IRQ sources are enabled.
2. On EF10 there is no master IRQ enable bit, so we cannot expect to
defer IRQs without tearing down event queues. (Though I don't think
we will need to keep any event queues around while the device is down,
as we do for VFDI on Siena.)
3. synchronize_irq() only waits for a running IRQ handler to finish,
not for any propagation through IRQ controllers. Therefore an IRQ may
still be received and handled after efx_stop_interrupts() returns.
IRQ handlers can then race with channel reallocation.
To fix this:
a. Introduce a software IRQ enable flag. So long as this is clear,
IRQ handlers will only acknowledge IRQs and not touch the channel
structures.
b. Define a new struct efx_msi_context as the context for MSIs. This
is never reallocated and is sufficient to find the software enable
flag and the channel structure. It also includes the channel/IRQ
name, which was previously separated out as it must also not be
reallocated.
c. Split efx_{start,stop}_interrupts() into
efx_{,soft_}_{enable,disable}_interrupts(). The 'soft' functions
don't touch the hardware master enable flag (if it exists) and don't
reinitialise or tear down channels with the keep_eventq flag set.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
|
| H A D | efx.c | d8291187 Fri Oct 05 17:35:41 CDT 2012 Ben Hutchings <bhutchings@solarflare.com> sfc: Rework IRQ enable/disable
There are many problems with the current efx_stop_interrupts() and
efx_start_interrupts():
1. On Siena, it is unsafe to disable the master IRQ enable bit
(DRV_INT_EN_KER) while any IRQ sources are enabled.
2. On EF10 there is no master IRQ enable bit, so we cannot expect to
defer IRQs without tearing down event queues. (Though I don't think
we will need to keep any event queues around while the device is down,
as we do for VFDI on Siena.)
3. synchronize_irq() only waits for a running IRQ handler to finish,
not for any propagation through IRQ controllers. Therefore an IRQ may
still be received and handled after efx_stop_interrupts() returns.
IRQ handlers can then race with channel reallocation.
To fix this:
a. Introduce a software IRQ enable flag. So long as this is clear,
IRQ handlers will only acknowledge IRQs and not touch the channel
structures.
b. Define a new struct efx_msi_context as the context for MSIs. This
is never reallocated and is sufficient to find the software enable
flag and the channel structure. It also includes the channel/IRQ
name, which was previously separated out as it must also not be
reallocated.
c. Split efx_{start,stop}_interrupts() into
efx_{,soft_}_{enable,disable}_interrupts(). The 'soft' functions
don't touch the hardware master enable flag (if it exists) and don't
reinitialise or tear down channels with the keep_eventq flag set.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
d8291187 Fri Oct 05 17:35:41 CDT 2012 Ben Hutchings <bhutchings@solarflare.com> sfc: Rework IRQ enable/disable
There are many problems with the current efx_stop_interrupts() and
efx_start_interrupts():
1. On Siena, it is unsafe to disable the master IRQ enable bit
(DRV_INT_EN_KER) while any IRQ sources are enabled.
2. On EF10 there is no master IRQ enable bit, so we cannot expect to
defer IRQs without tearing down event queues. (Though I don't think
we will need to keep any event queues around while the device is down,
as we do for VFDI on Siena.)
3. synchronize_irq() only waits for a running IRQ handler to finish,
not for any propagation through IRQ controllers. Therefore an IRQ may
still be received and handled after efx_stop_interrupts() returns.
IRQ handlers can then race with channel reallocation.
To fix this:
a. Introduce a software IRQ enable flag. So long as this is clear,
IRQ handlers will only acknowledge IRQs and not touch the channel
structures.
b. Define a new struct efx_msi_context as the context for MSIs. This
is never reallocated and is sufficient to find the software enable
flag and the channel structure. It also includes the channel/IRQ
name, which was previously separated out as it must also not be
reallocated.
c. Split efx_{start,stop}_interrupts() into
efx_{,soft_}_{enable,disable}_interrupts(). The 'soft' functions
don't touch the hardware master enable flag (if it exists) and don't
reinitialise or tear down channels with the keep_eventq flag set.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
|