Staging: Octeon Ethernet: Convert to NAPI.

Convert the driver to be a reasonably well behaved NAPI citizen.

There is one NAPI instance per CPU shared between all input ports.  As
receive backlog increases, NAPI is scheduled on additional CPUs.

Receive buffer refill code factored out so it can also be called from
the periodic timer.  This is needed to recover from temporary buffer
starvation conditions.

Signed-off-by: David Daney <ddaney@caviumnetworks.com>
To: linux-mips@linux-mips.org
To: gregkh@suse.de
Patchwork: http://patchwork.linux-mips.org/patch/839/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 20 insertions, 32 deletions

diff --git a/drivers/staging/octeon/ethernet.c b/drivers/staging/octeon/ethernet.c
index 973178a80c93..9f5b7419e777 100644
--- a/drivers/staging/octeon/ethernet.c
+++ b/drivers/staging/octeon/ethernet.c
@@ -104,6 +104,16 @@ MODULE_PARM_DESC(pow_send_list, "\n"
 	"\t\"eth2,spi3,spi7\" would cause these three devices to transmit\n"
 	"\tusing the pow_send_group.");
 
+int max_rx_cpus = -1;
+module_param(max_rx_cpus, int, 0444);
+MODULE_PARM_DESC(max_rx_cpus, "\n"
+	"\t\tThe maximum number of CPUs to use for packet reception.\n"
+	"\t\tUse -1 to use all available CPUs.");
+
+int rx_napi_weight = 32;
+module_param(rx_napi_weight, int, 0444);
+MODULE_PARM_DESC(rx_napi_weight, "The NAPI WEIGHT parameter.");
+
 /*
  * The offset from mac_addr_base that should be used for the next port
  * that is configured.  By convention, if any mgmt ports exist on the
@@ -149,6 +159,15 @@ static void cvm_do_timer(unsigned long arg)
 	} else {
 		port = 0;
 		/*
+		 * FPA 0 may have been drained, try to refill it if we
+		 * need more than num_packet_buffers / 2, otherwise
+		 * normal receive processing will refill it.  If it
+		 * were drained, no packets could be received so
+		 * cvm_oct_napi_poll would never be invoked to do the
+		 * refill.
+		 */
+		cvm_oct_rx_refill_pool(num_packet_buffers / 2);
+		/*
 		 * All ports have been polled. Start the next iteration through
 		 * the ports in one second.
 		 */
@@ -161,7 +180,6 @@ static void cvm_do_timer(unsigned long arg)
  */
 static __init void cvm_oct_configure_common_hw(void)
 {
-	int r;
 	/* Setup the FPA */
 	cvmx_fpa_enable();
 	cvm_oct_mem_fill_fpa(CVMX_FPA_PACKET_POOL, CVMX_FPA_PACKET_POOL_SIZE,
@@ -176,17 +194,6 @@ static __init void cvm_oct_configure_common_hw(void)
 		cvmx_helper_setup_red(num_packet_buffers / 4,
 				      num_packet_buffers / 8);
 
-	/* Register an IRQ hander for to receive POW interrupts */
-	r = request_irq(OCTEON_IRQ_WORKQ0 + pow_receive_group,
-			cvm_oct_do_interrupt, IRQF_SHARED, "Ethernet",
-			cvm_oct_device);
-
-#if defined(CONFIG_SMP) && 0
-	if (USE_MULTICORE_RECEIVE) {
-		irq_set_affinity(OCTEON_IRQ_WORKQ0 + pow_receive_group,
-				 cpu_online_mask);
-	}
-#endif
 }
 
 /**
@@ -616,7 +623,6 @@ static int __init cvm_oct_init_module(void)
 		cvm_oct_mac_addr_offset = 0;
 
 	cvm_oct_proc_initialize();
-	cvm_oct_rx_initialize();
 	cvm_oct_configure_common_hw();
 
 	cvmx_helper_initialize_packet_io_global();
@@ -781,25 +787,7 @@ static int __init cvm_oct_init_module(void)
 		}
 	}
 
-	if (INTERRUPT_LIMIT) {
-		/*
-		 * Set the POW timer rate to give an interrupt at most
-		 * INTERRUPT_LIMIT times per second.
-		 */
-		cvmx_write_csr(CVMX_POW_WQ_INT_PC,
-			       octeon_bootinfo->eclock_hz / (INTERRUPT_LIMIT *
-							     16 * 256) << 8);
-
-		/*
-		 * Enable POW timer interrupt. It will count when
-		 * there are packets available.
-		 */
-		cvmx_write_csr(CVMX_POW_WQ_INT_THRX(pow_receive_group),
-			       0x1ful << 24);
-	} else {
-		/* Enable POW interrupt when our port has at least one packet */
-		cvmx_write_csr(CVMX_POW_WQ_INT_THRX(pow_receive_group), 0x1001);
-	}
+	cvm_oct_rx_initialize();
 
 	/* Enable the poll timer for checking RGMII status */
 	init_timer(&cvm_oct_poll_timer);