[PATCH] davinci_emac: Add cpu_freq support

From: Manjunathappa, Prakash
Date: Mon Apr 09 2012 - 07:07:13 EST


Reconfigure interrupt coalesce parameter for changed emac bus_freq
due to DVFS.

Signed-off-by: Manjunathappa, Prakash <prakash.pm@xxxxxx>
---
drivers/net/ethernet/ti/davinci_emac.c | 60 ++++++++++++++++++++++++++++++++
1 files changed, 60 insertions(+), 0 deletions(-)

diff --git a/drivers/net/ethernet/ti/davinci_emac.c b/drivers/net/ethernet/ti/davinci_emac.c
index 174a334..11d3bd7 100644
--- a/drivers/net/ethernet/ti/davinci_emac.c
+++ b/drivers/net/ethernet/ti/davinci_emac.c
@@ -50,6 +50,7 @@
#include <linux/ctype.h>
#include <linux/spinlock.h>
#include <linux/dma-mapping.h>
+#include <linux/cpufreq.h>
#include <linux/clk.h>
#include <linux/platform_device.h>
#include <linux/semaphore.h>
@@ -344,6 +345,9 @@ struct emac_priv {
/*platform specific members*/
void (*int_enable) (void);
void (*int_disable) (void);
+#ifdef CONFIG_CPU_FREQ
+ struct notifier_block freq_transition;
+#endif
};

/* clock frequency for EMAC */
@@ -1761,6 +1765,46 @@ static const struct net_device_ops emac_netdev_ops = {
#endif
};

+#ifdef CONFIG_CPU_FREQ
+static int davinci_emac_cpufreq_transition(struct notifier_block *nb,
+ unsigned long val, void *data)
+{
+ int ret = 0;
+ struct emac_priv *priv;
+
+ priv = container_of(nb, struct emac_priv, freq_transition);
+ if (priv->coal_intvl != 0) {
+ if (val == CPUFREQ_POSTCHANGE) {
+ if (emac_bus_frequency != clk_get_rate(emac_clk)) {
+ struct ethtool_coalesce coal;
+
+ emac_bus_frequency = clk_get_rate(emac_clk);
+
+ priv->bus_freq_mhz = (u32)(emac_bus_frequency /
+ 1000000);
+ coal.rx_coalesce_usecs = (priv->coal_intvl
+ << 4);
+ ret = emac_set_coalesce(priv->ndev, &coal);
+ }
+ }
+ }
+ return ret;
+}
+
+static inline int davinci_emac_cpufreq_register(struct emac_priv *priv)
+{
+ priv->freq_transition.notifier_call = davinci_emac_cpufreq_transition;
+ return cpufreq_register_notifier(&priv->freq_transition,
+ CPUFREQ_TRANSITION_NOTIFIER);
+}
+
+static inline void davinci_emac_cpufreq_deregister(struct emac_priv *priv)
+{
+ cpufreq_unregister_notifier(&priv->freq_transition,
+ CPUFREQ_TRANSITION_NOTIFIER);
+}
+#endif
+
/**
* davinci_emac_probe: EMAC device probe
* @pdev: The DaVinci EMAC device that we are removing
@@ -1925,8 +1969,21 @@ static int __devinit davinci_emac_probe(struct platform_device *pdev)
"(regs: %p, irq: %d)\n",
(void *)priv->emac_base_phys, ndev->irq);
}
+
+#ifdef CONFIG_CPU_FREQ
+ rc = davinci_emac_cpufreq_register(priv);
+ if (rc) {
+ dev_err(&pdev->dev, "error in register_netdev\n");
+ rc = -ENODEV;
+ goto cpufreq_reg_err;
+ }
+#endif
return 0;

+#ifdef CONFIG_CPU_FREQ
+cpufreq_reg_err:
+ unregister_netdev(ndev);
+#endif
netdev_reg_err:
clk_disable(emac_clk);
no_irq_res:
@@ -1973,6 +2030,9 @@ static int __devexit davinci_emac_remove(struct platform_device *pdev)

release_mem_region(res->start, resource_size(res));

+#ifdef CONFIG_CPU_FREQ
+ davinci_emac_cpufreq_deregister(priv);
+#endif
unregister_netdev(ndev);
iounmap(priv->remap_addr);
free_netdev(ndev);
--
1.7.1

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