On 09/04/2012 09:36 AM, Vaibhav Hiremath wrote:

On 9/4/2012 11:44 AM, AnilKumar, Chimata wrote:

quoted

Hi Marc,

On Tue, Sep 04, 2012 at 02:09:15, Marc Kleine-Budde wrote:

quoted

On 09/03/2012 01:52 PM, AnilKumar Ch wrote:

quoted

Add D_CAN raminit support to C_CAN driver to enable D_CAN RAM.
DCAN RAM holds all the message objects during transmission or
receiving of data. This initialization/de-initialization should
be done in synchronous with D_CAN clock.

Signed-off-by: AnilKumar Ch <redacted>
---
 drivers/net/can/c_can/c_can.c          |   13 ++++++++++++
 drivers/net/can/c_can/c_can.h          |    2 ++
 drivers/net/can/c_can/c_can_platform.c |   10 +++++++++
 include/linux/can/platform/c_can.h     |   36 ++++++++++++++++++++++++++++++++
 4 files changed, 61 insertions(+)
 create mode 100644 include/linux/can/platform/c_can.h

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index aa6c5eb..c175410 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c

@@ -214,6 +214,12 @@ static inline void c_can_pm_runtime_put_sync(const struct c_can_priv *priv)
 		pm_runtime_put_sync(priv->device);
 }
 
+static inline void c_can_reset_ram(const struct c_can_priv *priv, bool enable)
+{
+	if (priv->ram_init)
+		priv->ram_init(priv->instance, enable);
+}
+
 static inline int get_tx_next_msg_obj(const struct c_can_priv *priv)
 {
 	return (priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) +

@@ -1071,6 +1077,8 @@ static int c_can_open(struct net_device *dev)
 	struct c_can_priv *priv = netdev_priv(dev);
 
 	c_can_pm_runtime_get_sync(priv);
+	/* Initialize DCAN RAM */
+	c_can_reset_ram(priv, true);
 
 	/* open the can device */
 	err = open_candev(dev);

@@ -1099,6 +1107,8 @@ static int c_can_open(struct net_device *dev)
 exit_irq_fail:
 	close_candev(dev);
 exit_open_fail:
+	/* De-Initialize DCAN RAM */
+	c_can_reset_ram(priv, false);
 	c_can_pm_runtime_put_sync(priv);
 	return err;
 }

@@ -1112,6 +1122,9 @@ static int c_can_close(struct net_device *dev)
 	c_can_stop(dev);
 	free_irq(dev->irq, dev);
 	close_candev(dev);
+
+	/* De-Initialize DCAN RAM */
+	c_can_reset_ram(priv, false);
 	c_can_pm_runtime_put_sync(priv);
 
 	return 0;

diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
index 1437a6d..5f6339c 100644
--- a/drivers/net/can/c_can/c_can.h
+++ b/drivers/net/can/c_can/c_can.h

@@ -166,6 +166,8 @@ struct c_can_priv {
 	unsigned int tx_echo;
 	void *priv;		/* for board-specific data */
 	u16 irqstatus;
+	unsigned int instance;
+	void (*ram_init) (unsigned int instance, bool enable);
 };
 
 struct net_device *alloc_c_can_dev(void);

diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c
index c351975..c6963b2 100644
--- a/drivers/net/can/c_can/c_can_platform.c
+++ b/drivers/net/can/c_can/c_can_platform.c

@@ -34,6 +34,7 @@
 #include <linux/of_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/pinctrl/consumer.h>
+#include <linux/can/platform/c_can.h>
 
 #include <linux/can/dev.h>
 

@@ -98,6 +99,7 @@ static int __devinit c_can_plat_probe(struct platform_device *pdev)
 	struct net_device *dev;
 	struct c_can_priv *priv;
 	const struct of_device_id *match;
+	struct c_can_platform_data *pdata = NULL;
 	const struct platform_device_id *id;
 	struct pinctrl *pinctrl;
 	struct resource *mem;

@@ -179,6 +181,14 @@ static int __devinit c_can_plat_probe(struct platform_device *pdev)
 		priv->can.ctrlmode_supported |= CAN_CTRLMODE_3_SAMPLES;
 		priv->read_reg = c_can_plat_read_reg_aligned_to_16bit;
 		priv->write_reg = c_can_plat_write_reg_aligned_to_16bit;
+		pdata = pdev->dev.platform_data;
+		if (!pdata) {
+			dev_err(&pdev->dev, "d_can platform data missing\n");
+			ret = -EINVAL;

Is the ram_init mandatory on all d_can? There might be non omap d_can users.

As per AM335x specifications d_can module should have ram_init.
In that case it's better to print warning and break the switch.

As far as I know, "ram_init" is part of IP spec, how it is controlled
does varies based on SoC integration.

Thanks for your insight. Leave the code as it is. If there is another
d_can user we know more and will improve/fix the code :)

Marc

-- 
Pengutronix e.K.                  | Marc Kleine-Budde           |
Industrial Linux Solutions        | Phone: +49-231-2826-924     |
Vertretung West/Dortmund          | Fax:   +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686  | http://www.pengutronix.de   |

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