[PATCH] davinci_emac: Add cpu_freq support

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

Signed-off-by: Manjunathappa, Prakash <redacted>
---
 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

Hello.

On 09-04-2012 14:49, Manjunathappa, Prakash wrote:

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

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

[...]

    These 3 *if*s could be collapsed into one, and so indentation level 
lowered significantly.

    Really?

    This is considered a bad practice to use #ifdef in the body of function.
Define the faunction you call here as empty inline in case CONFIG_CPU_FREQ is 
not defined instead. The same about davinci_emac_cpufreq_register().

WBR, Sergei

On Mon, 2012-04-09 at 16:19 +0530, Manjunathappa, Prakash wrote:

[...]

Ick.  Why don't you break up emac_set_coalesce() so that you can push
this one value to the hardware without faking up a struct
ethtool_coalesce?  Don't you need to push it on reset/resume anyway?

Ben.

-- 
Ben Hutchings, Staff Engineer, Solarflare
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

Hi Sergei,

On Mon, Apr 09, 2012 at 16:59:52, Sergei Shtylyov wrote:

Hello.

On 09-04-2012 14:49, Manjunathappa, Prakash wrote:

quoted

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

quoted

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

quoted

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

[...]

quoted

@@ -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)) {

    These 3 *if*s could be collapsed into one, and so indentation level 
lowered significantly.

Ok I will tie them with "&&".

quoted

+				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");

    Really?

Ahh, my bad... I will fix this.

quoted

+		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

    This is considered a bad practice to use #ifdef in the body of function.
Define the faunction you call here as empty inline in case CONFIG_CPU_FREQ is 
not defined instead. The same about davinci_emac_cpufreq_register().

Ok. I will correct this as you suggested.

Thanks,
Prakash

WBR, Sergei