[PATCH v2 1/2] can: m_can: move Message RAM initialization to function

[PATCH v2 1/2] can: m_can: move Message RAM initialization to function

[Quentin Schulz]

To avoid possible ECC/parity checksum errors when reading an
uninitialized buffer, the entire Message RAM is initialized when probing
the driver. This initialization is done in the same function reading the
Device Tree properties.

This patch moves the RAM initialization to a separate function so it can
be called separately from device initialization from Device Tree.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
---
 drivers/net/can/m_can/m_can.c | 24 +++++++++++++++---------
 1 file changed, 15 insertions(+), 9 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index bf8fdaeb955e..3f0445440146 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1489,6 +1489,20 @@ static int register_m_can_dev(struct net_device *dev)
 	return register_candev(dev);
 }
 
+static void m_can_init_ram(struct m_can_priv *priv)
+{
+	int end, i, start;
+
+	/* initialize the entire Message RAM in use to avoid possible
+	 * ECC/parity checksum errors when reading an uninitialized buffer
+	 */
+	start = priv->mcfg[MRAM_SIDF].off;
+	end = priv->mcfg[MRAM_TXB].off +
+		priv->mcfg[MRAM_TXB].num * TXB_ELEMENT_SIZE;
+	for (i = start; i < end; i += 4)
+		writel(0x0, priv->mram_base + i);
+}
+
 static void m_can_of_parse_mram(struct m_can_priv *priv,
 				const u32 *mram_config_vals)
 {
@@ -1529,15 +1543,7 @@ static void m_can_of_parse_mram(struct m_can_priv *priv,
 		priv->mcfg[MRAM_TXE].off, priv->mcfg[MRAM_TXE].num,
 		priv->mcfg[MRAM_TXB].off, priv->mcfg[MRAM_TXB].num);
 
-	/* initialize the entire Message RAM in use to avoid possible
-	 * ECC/parity checksum errors when reading an uninitialized buffer
-	 */
-	start = priv->mcfg[MRAM_SIDF].off;
-	end = priv->mcfg[MRAM_TXB].off +
-		priv->mcfg[MRAM_TXB].num * TXB_ELEMENT_SIZE;
-	for (i = start; i < end; i += 4)
-		writel(0x0, priv->mram_base + i);
-
+	m_can_init_ram(priv);
 }
 
 static int m_can_plat_probe(struct platform_device *pdev)
-- 
2.11.0

[PATCH v2 2/2] can: m_can: add deep Suspend/Resume support

[Quentin Schulz]

This adds Power Management deep Suspend/Resume support for Bosch M_CAN
chip.

When the system resumes from deep sleep, the chip needs to be fully
reinitialized (RAM, chip, clocks, irq, candev, ...) to be functional.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
---
 drivers/net/can/m_can/m_can.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 3f0445440146..9e0143b528f1 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1670,12 +1670,10 @@ static __maybe_unused int m_can_suspend(struct device *dev)
 	struct m_can_priv *priv = netdev_priv(ndev);
 
 	if (netif_running(ndev)) {
-		netif_stop_queue(ndev);
 		netif_device_detach(ndev);
+		m_can_close(ndev);
 	}
 
-	/* TODO: enter low power */
-
 	priv->can.state = CAN_STATE_SLEEPING;
 
 	return 0;
@@ -1686,13 +1684,13 @@ static __maybe_unused int m_can_resume(struct device *dev)
 	struct net_device *ndev = dev_get_drvdata(dev);
 	struct m_can_priv *priv = netdev_priv(ndev);
 
-	/* TODO: exit low power */
+	m_can_init_ram(priv);
 
 	priv->can.state = CAN_STATE_ERROR_ACTIVE;
 
 	if (netif_running(ndev)) {
+		m_can_open(ndev);
 		netif_device_attach(ndev);
-		netif_start_queue(ndev);
 	}
 
 	return 0;
-- 
2.11.0

Re: [PATCH v2 2/2] can: m_can: add deep Suspend/Resume support

[Quentin Schulz]

Hum, forgot the changelog.

On 03/05/2017 14:37, Quentin Schulz wrote:
> This adds Power Management deep Suspend/Resume support for Bosch M_CAN
> chip.
> 
> When the system resumes from deep sleep, the chip needs to be fully
> reinitialized (RAM, chip, clocks, irq, candev, ...) to be functional.
> 
> Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
> ---

v2:
 - fix erroneous commit log,

>  drivers/net/can/m_can/m_can.c | 8 +++-----
>  1 file changed, 3 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
> index 3f0445440146..9e0143b528f1 100644
> --- a/drivers/net/can/m_can/m_can.c
> +++ b/drivers/net/can/m_can/m_can.c
> @@ -1670,12 +1670,10 @@ static __maybe_unused int m_can_suspend(struct device *dev)
>  	struct m_can_priv *priv = netdev_priv(ndev);
>  
>  	if (netif_running(ndev)) {
> -		netif_stop_queue(ndev);
>  		netif_device_detach(ndev);
> +		m_can_close(ndev);
>  	}
>  
> -	/* TODO: enter low power */
> -
>  	priv->can.state = CAN_STATE_SLEEPING;
>  
>  	return 0;
> @@ -1686,13 +1684,13 @@ static __maybe_unused int m_can_resume(struct device *dev)
>  	struct net_device *ndev = dev_get_drvdata(dev);
>  	struct m_can_priv *priv = netdev_priv(ndev);
>  
> -	/* TODO: exit low power */
> +	m_can_init_ram(priv);
>  
>  	priv->can.state = CAN_STATE_ERROR_ACTIVE;
>  
>  	if (netif_running(ndev)) {
> +		m_can_open(ndev);
>  		netif_device_attach(ndev);
> -		netif_start_queue(ndev);
>  	}
>  
>  	return 0;
> 

-- 
Quentin Schulz, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com