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[PATCH v4 1/4] can: m_can: move Message RAM initialization to function

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  [PATCH v4 1/4] can: m_can: move Message RAM initialization to function Quentin Schulz <quentin.schulz@free-electrons.com> - 2017-05-05 16:00 +0200
    [PATCH v4 3/4] can: m_can: factorize clock gating and ungating Quentin Schulz <quentin.schulz@free-electrons.com> - 2017-05-05 16:00 +0200
    [PATCH v4 2/4] can: m_can: make m_can_start and m_can_stop symmetric Quentin Schulz <quentin.schulz@free-electrons.com> - 2017-05-05 16:00 +0200

#1636395 — [PATCH v4 1/4] can: m_can: move Message RAM initialization to function

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>
---

v4:
  - remove unused variables from m_can_of_parse_mram,

 drivers/net/can/m_can/m_can.c | 26 +++++++++++++++-----------
 1 file changed, 15 insertions(+), 11 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index bf8fdaeb955e..5da1bdb202a3 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1489,11 +1489,23 @@ 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)
 {
-	int i, start, end;
-
 	priv->mcfg[MRAM_SIDF].off = mram_config_vals[0];
 	priv->mcfg[MRAM_SIDF].num = mram_config_vals[1];
 	priv->mcfg[MRAM_XIDF].off = priv->mcfg[MRAM_SIDF].off +
@@ -1529,15 +1541,7 @@ 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

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#1636396 — [PATCH v4 3/4] can: m_can: factorize clock gating and ungating

This creates a function to ungate M_CAN clocks and another to gate the
same clocks, then swaps all gating/ungating code with their respective
function.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
---

added in v4

 drivers/net/can/m_can/m_can.c | 45 +++++++++++++++++++++++++------------------
 1 file changed, 26 insertions(+), 19 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 6115dede671e..653b304d7091 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -621,10 +621,8 @@ static int __m_can_get_berr_counter(const struct net_device *dev,
 	return 0;
 }
 
-static int m_can_get_berr_counter(const struct net_device *dev,
-				  struct can_berr_counter *bec)
+static int m_can_clk_start(struct m_can_priv *priv)
 {
-	struct m_can_priv *priv = netdev_priv(dev);
 	int err;
 
 	err = clk_prepare_enable(priv->hclk);
@@ -632,15 +630,31 @@ static int m_can_get_berr_counter(const struct net_device *dev,
 		return err;
 
 	err = clk_prepare_enable(priv->cclk);
-	if (err) {
+	if (err)
 		clk_disable_unprepare(priv->hclk);
-		return err;
-	}
 
-	__m_can_get_berr_counter(dev, bec);
+	return err;
+}
 
+static void m_can_clk_stop(struct m_can_priv *priv)
+{
 	clk_disable_unprepare(priv->cclk);
 	clk_disable_unprepare(priv->hclk);
+}
+
+static int m_can_get_berr_counter(const struct net_device *dev,
+				  struct can_berr_counter *bec)
+{
+	struct m_can_priv *priv = netdev_priv(dev);
+	int err;
+
+	err = m_can_clk_start(priv);
+	if (err)
+		return err;
+
+	__m_can_get_berr_counter(dev, bec);
+
+	m_can_clk_stop(priv);
 
 	return 0;
 }
@@ -1276,19 +1290,15 @@ static int m_can_open(struct net_device *dev)
 	struct m_can_priv *priv = netdev_priv(dev);
 	int err;
 
-	err = clk_prepare_enable(priv->hclk);
+	err = m_can_clk_start(priv);
 	if (err)
 		return err;
 
-	err = clk_prepare_enable(priv->cclk);
-	if (err)
-		goto exit_disable_hclk;
-
 	/* open the can device */
 	err = open_candev(dev);
 	if (err) {
 		netdev_err(dev, "failed to open can device\n");
-		goto exit_disable_cclk;
+		goto exit_disable_clks;
 	}
 
 	/* register interrupt handler */
@@ -1310,10 +1320,8 @@ static int m_can_open(struct net_device *dev)
 
 exit_irq_fail:
 	close_candev(dev);
-exit_disable_cclk:
-	clk_disable_unprepare(priv->cclk);
-exit_disable_hclk:
-	clk_disable_unprepare(priv->hclk);
+exit_disable_clks:
+	m_can_clk_stop(priv);
 	return err;
 }
 
@@ -1335,8 +1343,7 @@ static int m_can_close(struct net_device *dev)
 	netif_stop_queue(dev);
 	napi_disable(&priv->napi);
 	m_can_stop(dev);
-	clk_disable_unprepare(priv->hclk);
-	clk_disable_unprepare(priv->cclk);
+	m_can_clk_stop(priv);
 	free_irq(dev->irq, dev);
 	close_candev(dev);
 	can_led_event(dev, CAN_LED_EVENT_STOP);
-- 
2.11.0

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#1636399 — [PATCH v4 2/4] can: m_can: make m_can_start and m_can_stop symmetric

This moves clocks gating outside of the m_can_stop function as the
m_can_start function does not (and cannot, at least in current
implementation) ungate clocks. This way, both functions can now be used
symmetrically.

Signed-off-by: Quentin Schulz <quentin.schulz@free-electrons.com>
---

added in v4

 drivers/net/can/m_can/m_can.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/m_can/m_can.c b/drivers/net/can/m_can/m_can.c
index 5da1bdb202a3..6115dede671e 100644
--- a/drivers/net/can/m_can/m_can.c
+++ b/drivers/net/can/m_can/m_can.c
@@ -1324,9 +1324,6 @@ static void m_can_stop(struct net_device *dev)
 	/* disable all interrupts */
 	m_can_disable_all_interrupts(priv);
 
-	clk_disable_unprepare(priv->hclk);
-	clk_disable_unprepare(priv->cclk);
-
 	/* set the state as STOPPED */
 	priv->can.state = CAN_STATE_STOPPED;
 }
@@ -1338,6 +1335,8 @@ static int m_can_close(struct net_device *dev)
 	netif_stop_queue(dev);
 	napi_disable(&priv->napi);
 	m_can_stop(dev);
+	clk_disable_unprepare(priv->hclk);
+	clk_disable_unprepare(priv->cclk);
 	free_irq(dev->irq, dev);
 	close_candev(dev);
 	can_led_event(dev, CAN_LED_EVENT_STOP);
-- 
2.11.0

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