ENGR00256893-2 MX6Q/DL-Fix Ethernet performance issue when WAIT mode is active

All of the interrupts from the ENET block are not routed to
the GPC block. Hence ENET interrupts are not able to wake
up the SOC when the system is in WAIT mode. And the ENET
interrupt gets serviced only when another interrupt causes
the SOC to exit WAIT mode. This impacts the ENET performance.

To fix the issue two options:
1. Route the ENET interrupt to a GPIO. Need to enable the
CONFIG_MX6_ENET_IRQ_TO_GPIO in the config.
This patch provides support for routing the ENET interrupt
to GPIO_1_6. Routing to this GPIO requires no HW board mods.
If the GPIO_1_6 is being used for some other peripheral,
this patch can be followed to route the ENET interrupt to
any other GPIO though a HW mode maybe required.
2. If the GPIO mechanism cannot be used and is not enabled
by the above mentioned config, the patch will disable entry
to WAIT mode until ENET clock is active. When the ENET clock
is disabled, WAIT mode will be automatically enetered.

Signed-off-by: Ranjani Vaidyanathan <ra5478@freescale.com>

diff --git a/drivers/net/fec.c b/drivers/net/fec.c
index 5f0e4e0e3a3e8da5c41fd18ca4061425066067d2..fc65bdc96241e8fd0d1f67a043027f5a0cc5636a 100755 (executable)
--- a/drivers/net/fec.c
+++ b/drivers/net/fec.c
@@ -27,6 +27,7 @@
 #include <linux/string.h>
 #include <linux/ptrace.h>
 #include <linux/errno.h>
+#include <linux/gpio.h>
 #include <linux/ioport.h>
 #include <linux/slab.h>
 #include <linux/interrupt.h>
@@ -1866,6 +1867,17 @@ fec_probe(struct platform_device *pdev)
        if (pdata)
                fep->phy_interface = pdata->phy;
 
+#ifdef CONFIG_MX6_ENET_IRQ_TO_GPIO
+       gpio_request(pdata->gpio_irq, "gpio_enet_irq");
+       gpio_direction_input(pdata->gpio_irq);
+
+       irq = gpio_to_irq(pdata->gpio_irq);
+       ret = request_irq(irq, fec_enet_interrupt,
+                       IRQF_TRIGGER_RISING,
+                        pdev->name, ndev);
+       if (ret)
+               goto failed_irq;
+#else
        /* This device has up to three irqs on some platforms */
        for (i = 0; i < 3; i++) {
                irq = platform_get_irq(pdev, i);
@@ -1880,6 +1892,7 @@ fec_probe(struct platform_device *pdev)
                        goto failed_irq;
                }
        }
+#endif
 
        fep->clk = clk_get(&pdev->dev, "fec_clk");
        if (IS_ERR(fep->clk)) {
@@ -1930,11 +1943,15 @@ failed_init:
        clk_disable(fep->clk);
        clk_put(fep->clk);
 failed_clk:
+#ifdef CONFIG_MX6_ENET_IRQ_TO_GPIO
+       free_irq(irq, ndev);
+#else
        for (i = 0; i < 3; i++) {
                irq = platform_get_irq(pdev, i);
                if (irq > 0)
                        free_irq(irq, ndev);
        }
+#endif
 failed_irq:
        iounmap(fep->hwp);
 failed_ioremap:

diff --git a/include/linux/fec.h b/include/linux/fec.h
index 8f69cb58d458ed5f3d7698503f86c7f247934967..a9d659456ebab4e19d9e396d28434d64baf79c1c 100644 (file)
--- a/include/linux/fec.h
+++ b/include/linux/fec.h
@@ -3,7 +3,7 @@
  * Copyright (c) 2009 Orex Computed Radiography
  *   Baruch Siach <baruch@tkos.co.il>
  *
- * Copyright (C) 2010-2011 Freescale Semiconductor, Inc.
+ * Copyright (C) 2010-2013 Freescale Semiconductor, Inc.
  *
  * Header file for the FEC platform data
  *
@@ -21,6 +21,9 @@ struct fec_platform_data {
        int (*power_hibernate) (struct phy_device *);
        phy_interface_t phy;
        unsigned char mac[ETH_ALEN];
+#ifdef CONFIG_MX6_ENET_IRQ_TO_GPIO
+       unsigned int gpio_irq;
+#endif
 };
 
 #endif