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>
diff --git a/drivers/net/ethernet/sfc/siena.c b/drivers/net/ethernet/sfc/siena.c
index 65cb5e4..f054258 100644
--- a/drivers/net/ethernet/sfc/siena.c
+++ b/drivers/net/ethernet/sfc/siena.c
@@ -35,8 +35,6 @@
{
efx_dword_t timer_cmd;
- BUILD_BUG_ON(EFX_IRQ_MOD_MAX > (1 << FRF_CZ_TC_TIMER_VAL_WIDTH));
-
if (channel->irq_moderation)
EFX_POPULATE_DWORD_2(timer_cmd,
FRF_CZ_TC_TIMER_MODE,
@@ -216,7 +214,15 @@
static int siena_probe_nvconfig(struct efx_nic *efx)
{
- return efx_mcdi_get_board_cfg(efx, efx->net_dev->perm_addr, NULL, NULL);
+ u32 caps = 0;
+ int rc;
+
+ rc = efx_mcdi_get_board_cfg(efx, efx->net_dev->perm_addr, NULL, &caps);
+
+ efx->timer_quantum_ns =
+ (caps & (1 << MC_CMD_CAPABILITIES_TURBO_ACTIVE_LBN)) ?
+ 3072 : 6144; /* 768 cycles */
+ return rc;
}
static int siena_probe_nic(struct efx_nic *efx)
@@ -644,6 +650,7 @@
.phys_addr_channels = 32, /* Hardware limit is 64, but the legacy
* interrupt handler only supports 32
* channels */
+ .timer_period_max = 1 << FRF_CZ_TC_TIMER_VAL_WIDTH,
.tx_dc_base = 0x88000,
.rx_dc_base = 0x68000,
.offload_features = (NETIF_F_IP_CSUM | NETIF_F_IPV6_CSUM |
