[net-next,3/3] sfc: work around TRIGGER_INTERRUPT command not working on SFC9140

diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
index c4cd6b0..6fe1d0b 100644
--- a/drivers/net/ethernet/sfc/ef10.c
+++ b/drivers/net/ethernet/sfc/ef10.c
@@ -2048,14 +2048,18 @@  static irqreturn_t efx_ef10_legacy_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
-static void efx_ef10_irq_test_generate(struct efx_nic *efx)
+static int efx_ef10_irq_test_generate(struct efx_nic *efx)
 {
 	MCDI_DECLARE_BUF(inbuf, MC_CMD_TRIGGER_INTERRUPT_IN_LEN);
 
+	if (efx_mcdi_set_workaround(efx, MC_CMD_WORKAROUND_BUG41750, true,
+				    NULL) == 0)
+		return -ENOTSUPP;
+
 	BUILD_BUG_ON(MC_CMD_TRIGGER_INTERRUPT_OUT_LEN != 0);
 
 	MCDI_SET_DWORD(inbuf, TRIGGER_INTERRUPT_IN_INTR_LEVEL, efx->irq_level);
-	(void) efx_mcdi_rpc(efx, MC_CMD_TRIGGER_INTERRUPT,
+	return efx_mcdi_rpc(efx, MC_CMD_TRIGGER_INTERRUPT,
 			    inbuf, sizeof(inbuf), NULL, 0, NULL);
 }
 
diff --git a/drivers/net/ethernet/sfc/farch.c b/drivers/net/ethernet/sfc/farch.c
index 4c83739..4762ec4 100644
--- a/drivers/net/ethernet/sfc/farch.c
+++ b/drivers/net/ethernet/sfc/farch.c
@@ -1477,9 +1477,10 @@  void efx_farch_irq_disable_master(struct efx_nic *efx)
  * Interrupt must already have been enabled, otherwise nasty things
  * may happen.
  */
-void efx_farch_irq_test_generate(struct efx_nic *efx)
+int efx_farch_irq_test_generate(struct efx_nic *efx)
 {
 	efx_farch_interrupts(efx, true, true);
+	return 0;
 }
 
 /* Process a fatal interrupt
diff --git a/drivers/net/ethernet/sfc/net_driver.h b/drivers/net/ethernet/sfc/net_driver.h
index 13b7f52..0a2504b 100644
--- a/drivers/net/ethernet/sfc/net_driver.h
+++ b/drivers/net/ethernet/sfc/net_driver.h
@@ -1275,7 +1275,7 @@  struct efx_nic_type {
 	int (*mcdi_poll_reboot)(struct efx_nic *efx);
 	void (*mcdi_reboot_detected)(struct efx_nic *efx);
 	void (*irq_enable_master)(struct efx_nic *efx);
-	void (*irq_test_generate)(struct efx_nic *efx);
+	int (*irq_test_generate)(struct efx_nic *efx);
 	void (*irq_disable_non_ev)(struct efx_nic *efx);
 	irqreturn_t (*irq_handle_msi)(int irq, void *dev_id);
 	irqreturn_t (*irq_handle_legacy)(int irq, void *dev_id);
diff --git a/drivers/net/ethernet/sfc/nic.c b/drivers/net/ethernet/sfc/nic.c
index 89b83e5..aa1945a 100644
--- a/drivers/net/ethernet/sfc/nic.c
+++ b/drivers/net/ethernet/sfc/nic.c
@@ -66,11 +66,11 @@  void efx_nic_event_test_start(struct efx_channel *channel)
 	channel->efx->type->ev_test_generate(channel);
 }
 
-void efx_nic_irq_test_start(struct efx_nic *efx)
+int efx_nic_irq_test_start(struct efx_nic *efx)
 {
 	efx->last_irq_cpu = -1;
 	smp_wmb();
-	efx->type->irq_test_generate(efx);
+	return efx->type->irq_test_generate(efx);
 }
 
 /* Hook interrupt handler(s)
diff --git a/drivers/net/ethernet/sfc/nic.h b/drivers/net/ethernet/sfc/nic.h
index d8b1694..73bee7e 100644
--- a/drivers/net/ethernet/sfc/nic.h
+++ b/drivers/net/ethernet/sfc/nic.h
@@ -746,12 +746,12 @@  static inline void efx_update_diff_stat(u64 *stat, u64 diff)
 
 /* Interrupts */
 int efx_nic_init_interrupt(struct efx_nic *efx);
-void efx_nic_irq_test_start(struct efx_nic *efx);
+int efx_nic_irq_test_start(struct efx_nic *efx);
 void efx_nic_fini_interrupt(struct efx_nic *efx);
 
 /* Falcon/Siena interrupts */
 void efx_farch_irq_enable_master(struct efx_nic *efx);
-void efx_farch_irq_test_generate(struct efx_nic *efx);
+int efx_farch_irq_test_generate(struct efx_nic *efx);
 void efx_farch_irq_disable_master(struct efx_nic *efx);
 irqreturn_t efx_farch_msi_interrupt(int irq, void *dev_id);
 irqreturn_t efx_farch_legacy_interrupt(int irq, void *dev_id);
diff --git a/drivers/net/ethernet/sfc/selftest.c b/drivers/net/ethernet/sfc/selftest.c
index 9d78830..cd38b44 100644
--- a/drivers/net/ethernet/sfc/selftest.c
+++ b/drivers/net/ethernet/sfc/selftest.c
@@ -135,11 +135,19 @@  static int efx_test_interrupts(struct efx_nic *efx,
 {
 	unsigned long timeout, wait;
 	int cpu;
+	int rc;
 
 	netif_dbg(efx, drv, efx->net_dev, "testing interrupts\n");
 	tests->interrupt = -1;
 
-	efx_nic_irq_test_start(efx);
+	rc = efx_nic_irq_test_start(efx);
+	if (rc == -ENOTSUPP) {
+		netif_dbg(efx, drv, efx->net_dev,
+			  "direct interrupt testing not supported\n");
+		tests->interrupt = 0;
+		return 0;
+	}
+
 	timeout = jiffies + IRQ_TIMEOUT;
 	wait = 1;
 
diff --git a/drivers/net/ethernet/sfc/selftest.h b/drivers/net/ethernet/sfc/selftest.h
index 009dbe8..32a4272 100644
--- a/drivers/net/ethernet/sfc/selftest.h
+++ b/drivers/net/ethernet/sfc/selftest.h
@@ -28,7 +28,7 @@  struct efx_loopback_self_tests {
 
 /* Efx self test results
  * For fields which are not counters, 1 indicates success and -1
- * indicates failure.
+ * indicates failure; 0 indicates test could not be run.
  */
 struct efx_self_tests {
 	/* online tests */