sfc: Correct interrupt timer quantum for Siena (normal and turbo mode)

We currently assume that the timer quantum for Siena is 5 us, the same
as for Falcon.  This is not correct; timer ticks are generated on a
rota which takes a minimum of 768 cycles (each event delivery or other
timer change will delay it by 3 cycles).  The timer quantum should be
6.144 or 3.072 us depending on whether turbo mode is active.

Replace EFX_IRQ_MOD_RESOLUTION with a timer_quantum_ns field in struct
efx_nic, initialised by the efx_nic_type::probe function.

While we're at it, replace EFX_IRQ_MOD_MAX with a timer_period_max
field in struct efx_nic_type.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 4cbd997e378b..8ce4d068bba5 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -624,6 +624,7 @@ struct efx_filter_state;
  * @membase_phys: Memory BAR value as physical address
  * @membase: Memory BAR value
  * @interrupt_mode: Interrupt mode
+ * @timer_quantum_ns: Interrupt timer quantum, in nanoseconds
  * @irq_rx_adaptive: Adaptive IRQ moderation enabled for RX event queues
  * @irq_rx_moderation: IRQ moderation time for RX event queues
  * @msg_enable: Log message enable flags
@@ -706,6 +707,7 @@ struct efx_nic {
         void __iomem *membase;
 
         enum efx_int_mode interrupt_mode;
+        unsigned int timer_quantum_ns;
         bool irq_rx_adaptive;
         unsigned int irq_rx_moderation;
         u32 msg_enable;
@@ -845,6 +847,7 @@ static inline unsigned int efx_port_num(struct efx_nic *efx)
  *      from &enum efx_init_mode.
  * @phys_addr_channels: Number of channels with physically addressed
  *      descriptors
+ * @timer_period_max: Maximum period of interrupt timer (in ticks)
  * @tx_dc_base: Base address in SRAM of TX queue descriptor caches
  * @rx_dc_base: Base address in SRAM of RX queue descriptor caches
  * @offload_features: net_device feature flags for protocol offload
@@ -889,6 +892,7 @@ struct efx_nic_type {
         unsigned int rx_buffer_padding;
         unsigned int max_interrupt_mode;
         unsigned int phys_addr_channels;
+        unsigned int timer_period_max;
         unsigned int tx_dc_base;
         unsigned int rx_dc_base;
         netdev_features_t offload_features;