sfc: Allow DRV_GEN events to be used outside of selftests

Formerly, efx_test_eventq_irq() assumed it was the only user of
driver generated events. Allow it to interoperate with other users.

We can create more than 16 channels, so align event codes with
a multiple of 256 not 16.
Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/sfc/net_driver.h

@@ -336,7 +336,7 @@ enum efx_rx_alloc_method {
  * @eventq: Event queue buffer
  * @eventq_read_ptr: Event queue read pointer
  * @last_eventq_read_ptr: Last event queue read pointer value.
- * @eventq_magic: Event queue magic value for driver-generated test events
+ * @magic_count: Event queue test event count
  * @irq_count: Number of IRQs since last adaptive moderation decision
  * @irq_mod_score: IRQ moderation score
  * @rx_alloc_level: Watermark based heuristic counter for pushing descriptors
@@ -367,7 +367,7 @@ struct efx_channel {
 	struct efx_special_buffer eventq;
 	unsigned int eventq_read_ptr;
 	unsigned int last_eventq_read_ptr;
-	unsigned int eventq_magic;
+	unsigned int magic_count;
 
 	unsigned int irq_count;
 	unsigned int irq_mod_score;

drivers/net/sfc/nic.c

@@ -79,6 +79,10 @@ MODULE_PARM_DESC(rx_xon_thresh_bytes, "RX fifo XON threshold");
 /* Depth of RX flush request fifo */
 #define EFX_RX_FLUSH_COUNT 4
 
+/* Magic value for efx_generate_test_event() */
+#define EFX_CHANNEL_MAGIC(_channel)			\
+	(0x00010100 + (_channel)->channel)
+
 /**************************************************************************
  *
  * Solarstorm hardware access
@@ -993,8 +997,10 @@ int efx_nic_process_eventq(struct efx_channel *channel, int budget)
 			}
 			break;
 		case FSE_AZ_EV_CODE_DRV_GEN_EV:
-			channel->eventq_magic = EFX_QWORD_FIELD(
-				event, FSF_AZ_DRV_GEN_EV_MAGIC);
+			if (EFX_QWORD_FIELD(event, FSF_AZ_DRV_GEN_EV_MAGIC)
+			    == EFX_CHANNEL_MAGIC(channel))
+				++channel->magic_count;
+
 			EFX_LOG(channel->efx, "channel %d received generated "
 				"event "EFX_QWORD_FMT"\n", channel->channel,
 				EFX_QWORD_VAL(event));
@@ -1088,12 +1094,9 @@ void efx_nic_remove_eventq(struct efx_channel *channel)
 }
 
 
-/* Generates a test event on the event queue.  A subsequent call to
- * process_eventq() should pick up the event and place the value of
- * "magic" into channel->eventq_magic;
- */
-void efx_nic_generate_test_event(struct efx_channel *channel, unsigned int magic)
+void efx_nic_generate_test_event(struct efx_channel *channel)
 {
+	unsigned int magic = EFX_CHANNEL_MAGIC(channel);
 	efx_qword_t test_event;
 
 	EFX_POPULATE_QWORD_2(test_event, FSF_AZ_EV_CODE,

drivers/net/sfc/nic.h

@@ -190,8 +190,7 @@ extern int efx_nic_rx_xoff_thresh, efx_nic_rx_xon_thresh;
 /* Interrupts and test events */
 extern int efx_nic_init_interrupt(struct efx_nic *efx);
 extern void efx_nic_enable_interrupts(struct efx_nic *efx);
-extern void efx_nic_generate_test_event(struct efx_channel *channel,
-					unsigned int magic);
+extern void efx_nic_generate_test_event(struct efx_channel *channel);
 extern void efx_nic_generate_interrupt(struct efx_nic *efx);
 extern void efx_nic_disable_interrupts(struct efx_nic *efx);
 extern void efx_nic_fini_interrupt(struct efx_nic *efx);

drivers/net/sfc/selftest.c

@@ -161,23 +161,17 @@ static int efx_test_interrupts(struct efx_nic *efx,
 static int efx_test_eventq_irq(struct efx_channel *channel,
 			       struct efx_self_tests *tests)
 {
-	unsigned int magic, count;
-
-	/* Channel specific code, limited to 20 bits */
-	magic = (0x00010150 + channel->channel);
-	EFX_LOG(channel->efx, "channel %d testing event queue with code %x\n",
-		channel->channel, magic);
+	unsigned int magic_count, count;
 
 	tests->eventq_dma[channel->channel] = -1;
 	tests->eventq_int[channel->channel] = -1;
 	tests->eventq_poll[channel->channel] = -1;
 
-	/* Reset flag and zero magic word */
+	magic_count = channel->magic_count;
 	channel->efx->last_irq_cpu = -1;
-	channel->eventq_magic = 0;
 	smp_wmb();
 
-	efx_nic_generate_test_event(channel, magic);
+	efx_nic_generate_test_event(channel);
 
 	/* Wait for arrival of interrupt */
 	count = 0;
@@ -187,7 +181,7 @@ static int efx_test_eventq_irq(struct efx_channel *channel,
 		if (channel->work_pending)
 			efx_process_channel_now(channel);
 
-		if (channel->eventq_magic == magic)
+		if (channel->magic_count != magic_count)
 			goto eventq_ok;
 	} while (++count < 2);
 
@@ -204,7 +198,7 @@ static int efx_test_eventq_irq(struct efx_channel *channel,
 
 	/* Check to see if event was received even if interrupt wasn't */
 	efx_process_channel_now(channel);
-	if (channel->eventq_magic == magic) {
+	if (channel->magic_count != magic_count) {
 		EFX_ERR(channel->efx, "channel %d event was generated, but "
 			"failed to trigger an interrupt\n", channel->channel);
 		tests->eventq_dma[channel->channel] = 1;