[PATCH v2 0/3] can: grcan: Bug fixes

[PATCH v2 0/3] can: grcan: Bug fixes

[Andreas Larsson]

These patches:
* makes sure that DMA memory is allocated properly
* avoids the tx errata workaround needlessly being applied
* fixes a bug where the driver can be left hanging without interrupts
  enabled

Andreas Larsson (2):
  can: grcan: Fix broken system id check for errata workaround needs
  can: grcan: Only use the napi poll budget for rx

Daniel Hellstrom (1):
  can: grcan: use ofdev->dev when allocating DMA memory

 drivers/net/can/grcan.c | 45 +++++++++++++++++++++--------------------
 1 file changed, 23 insertions(+), 22 deletions(-)

---

Changes in v2:
* Added "Fixes:" tags to all patches
* Small langague tweaks in patch descriptions for patch 1 and 3

-- 
2.17.1

[PATCH v2 1/3] can: grcan: use ofdev->dev when allocating DMA memory

[Andreas Larsson]

From: Daniel Hellstrom <daniel@gaisler.com>

Use the device of the device tree node should be rather than the device
of the struct net_device when allocating DMA buffers.

The driver got away with it on sparc32 until commit 53b7670e5735
("sparc: factor the dma coherent mapping into helper") after which the
driver oopses.

Fixes: 6cec9b07fe6a ("can: grcan: Add device driver for GRCAN and GRHCAN cores")

Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Signed-off-by: Andreas Larsson <andreas@gaisler.com>
---
 drivers/net/can/grcan.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c
index d0c5a7a60daf..f7c3cf941f61 100644
--- a/drivers/net/can/grcan.c
+++ b/drivers/net/can/grcan.c
@@ -248,6 +248,7 @@ struct grcan_device_config {
 struct grcan_priv {
 	struct can_priv can;	/* must be the first member */
 	struct net_device *dev;
+	struct device *ofdev_dev;
 	struct napi_struct napi;
 
 	struct grcan_registers __iomem *regs;	/* ioremap'ed registers */
@@ -921,7 +922,7 @@ static void grcan_free_dma_buffers(struct net_device *dev)
 	struct grcan_priv *priv = netdev_priv(dev);
 	struct grcan_dma *dma = &priv->dma;
 
-	dma_free_coherent(&dev->dev, dma->base_size, dma->base_buf,
+	dma_free_coherent(priv->ofdev_dev, dma->base_size, dma->base_buf,
 			  dma->base_handle);
 	memset(dma, 0, sizeof(*dma));
 }
@@ -946,7 +947,8 @@ static int grcan_allocate_dma_buffers(struct net_device *dev,
 
 	/* Extra GRCAN_BUFFER_ALIGNMENT to allow for alignment */
 	dma->base_size = lsize + ssize + GRCAN_BUFFER_ALIGNMENT;
-	dma->base_buf = dma_alloc_coherent(&dev->dev,
+
+	dma->base_buf = dma_alloc_coherent(priv->ofdev_dev,
 					   dma->base_size,
 					   &dma->base_handle,
 					   GFP_KERNEL);
@@ -1587,6 +1589,7 @@ static int grcan_setup_netdev(struct platform_device *ofdev,
 	memcpy(&priv->config, &grcan_module_config,
 	       sizeof(struct grcan_device_config));
 	priv->dev = dev;
+	priv->ofdev_dev = &ofdev->dev;
 	priv->regs = base;
 	priv->can.bittiming_const = &grcan_bittiming_const;
 	priv->can.do_set_bittiming = grcan_set_bittiming;
-- 
2.17.1

[PATCH v2 2/3] can: grcan: Fix broken system id check for errata workaround needs

[Andreas Larsson]

The systemid property was checked for in the wrong place of the
devicetree and compared to the wrong value.

Fixes: 6cec9b07fe6a ("can: grcan: Add device driver for GRCAN and GRHCAN cores")

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
---
 drivers/net/can/grcan.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c
index f7c3cf941f61..2f56d4bbb65c 100644
--- a/drivers/net/can/grcan.c
+++ b/drivers/net/can/grcan.c
@@ -241,7 +241,7 @@ struct grcan_device_config {
 		.rxsize		= GRCAN_DEFAULT_BUFFER_SIZE,	\
 		}
 
-#define GRCAN_TXBUG_SAFE_GRLIB_VERSION	0x4100
+#define GRCAN_TXBUG_SAFE_GRLIB_VERSION	4100
 #define GRLIB_VERSION_MASK		0xffff
 
 /* GRCAN private data structure */
@@ -1642,6 +1642,7 @@ static int grcan_setup_netdev(struct platform_device *ofdev,
 static int grcan_probe(struct platform_device *ofdev)
 {
 	struct device_node *np = ofdev->dev.of_node;
+	struct device_node *sysid_parent;
 	u32 sysid, ambafreq;
 	int irq, err;
 	void __iomem *base;
@@ -1650,10 +1651,15 @@ static int grcan_probe(struct platform_device *ofdev)
 	/* Compare GRLIB version number with the first that does not
 	 * have the tx bug (see start_xmit)
 	 */
-	err = of_property_read_u32(np, "systemid", &sysid);
-	if (!err && ((sysid & GRLIB_VERSION_MASK)
-		     >= GRCAN_TXBUG_SAFE_GRLIB_VERSION))
-		txbug = false;
+	sysid_parent = of_find_node_by_path("/ambapp0");
+	if (sysid_parent) {
+		of_node_get(sysid_parent);
+		err = of_property_read_u32(sysid_parent, "systemid", &sysid);
+		if (!err && ((sysid & GRLIB_VERSION_MASK)
+			     >= GRCAN_TXBUG_SAFE_GRLIB_VERSION))
+			txbug = false;
+		of_node_put(sysid_parent);
+	}
 
 	err = of_property_read_u32(np, "freq", &ambafreq);
 	if (err) {
-- 
2.17.1

[PATCH v2 3/3] can: grcan: Only use the napi poll budget for rx

[Andreas Larsson]

The previous split budget between tx and rx made it return not using the
entire budget but at the same time not having calling called
napi_complete. This sometimes led to the poll to not be called, and at
the same time having tx and rx interrupts disabled resulting in the
driver getting stuck.

Fixes: 6cec9b07fe6a ("can: grcan: Add device driver for GRCAN and GRHCAN cores")

Signed-off-by: Andreas Larsson <andreas@gaisler.com>
---
 drivers/net/can/grcan.c | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/drivers/net/can/grcan.c b/drivers/net/can/grcan.c
index 2f56d4bbb65c..cb98eadc3b93 100644
--- a/drivers/net/can/grcan.c
+++ b/drivers/net/can/grcan.c
@@ -1124,7 +1124,7 @@ static int grcan_close(struct net_device *dev)
 	return 0;
 }
 
-static int grcan_transmit_catch_up(struct net_device *dev, int budget)
+static void grcan_transmit_catch_up(struct net_device *dev)
 {
 	struct grcan_priv *priv = netdev_priv(dev);
 	unsigned long flags;
@@ -1132,7 +1132,7 @@ static int grcan_transmit_catch_up(struct net_device *dev, int budget)
 
 	spin_lock_irqsave(&priv->lock, flags);
 
-	work_done = catch_up_echo_skb(dev, budget, true);
+	work_done = catch_up_echo_skb(dev, -1, true);
 	if (work_done) {
 		if (!priv->resetting && !priv->closing &&
 		    !(priv->can.ctrlmode & CAN_CTRLMODE_LISTENONLY))
@@ -1146,8 +1146,6 @@ static int grcan_transmit_catch_up(struct net_device *dev, int budget)
 	}
 
 	spin_unlock_irqrestore(&priv->lock, flags);
-
-	return work_done;
 }
 
 static int grcan_receive(struct net_device *dev, int budget)
@@ -1229,19 +1227,13 @@ static int grcan_poll(struct napi_struct *napi, int budget)
 	struct net_device *dev = priv->dev;
 	struct grcan_registers __iomem *regs = priv->regs;
 	unsigned long flags;
-	int tx_work_done, rx_work_done;
-	int rx_budget = budget / 2;
-	int tx_budget = budget - rx_budget;
+	int work_done;
 
-	/* Half of the budget for receiving messages */
-	rx_work_done = grcan_receive(dev, rx_budget);
+	work_done = grcan_receive(dev, budget);
 
-	/* Half of the budget for transmitting messages as that can trigger echo
-	 * frames being received
-	 */
-	tx_work_done = grcan_transmit_catch_up(dev, tx_budget);
+	grcan_transmit_catch_up(dev);
 
-	if (rx_work_done < rx_budget && tx_work_done < tx_budget) {
+	if (work_done < budget) {
 		napi_complete(napi);
 
 		/* Guarantee no interference with a running reset that otherwise
@@ -1258,7 +1250,7 @@ static int grcan_poll(struct napi_struct *napi, int budget)
 		spin_unlock_irqrestore(&priv->lock, flags);
 	}
 
-	return rx_work_done + tx_work_done;
+	return work_done;
 }
 
 /* Work tx bug by waiting while for the risky situation to clear. If that fails,
-- 
2.17.1