Re: Dual SJA1000 can controllers on SMP system.

[Marc Kleine-Budde <mkl@pengutronix.de>]

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On 06/17/2013 03:46 PM, Mirza Krak wrote:
> My modifications to sja1000_platform.c are attached as a patch.
> 
> Wolfgang: Using spinlock_irqsave() and spinlock_irqrestore() was also my
> initial idea on the io functions but I tried this without it solving the
> problem. I could try this again to be sure.

Without problem locking it not work anyway. Try the attached patch (it's
compile time tested only).

Marc

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From bfebee863f12bee39dee9b00bfe9e3d8c1017d16 Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <mkl@pengutronix.de>
Date: Mon, 17 Jun 2013 16:09:13 +0200
Subject: [PATCH] HACK: can: sja1000_platform: add support for indirect
 register access
MIME-Version: 1.0
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Content-Transfer-Encoding: 8bit

Based on a privious work by Vänliga Hälsningar.

Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
---
 drivers/net/can/sja1000/sja1000_platform.c | 28 +++++++++++++++++++++++++---
 1 file changed, 25 insertions(+), 3 deletions(-)

diff --git a/drivers/net/can/sja1000/sja1000_platform.c b/drivers/net/can/sja1000/sja1000_platform.c
index 8e259c5..35f279c 100644
--- a/drivers/net/can/sja1000/sja1000_platform.c
+++ b/drivers/net/can/sja1000/sja1000_platform.c
@@ -37,14 +37,33 @@ MODULE_DESCRIPTION("Socket-CAN driver for SJA1000 on the platform bus");
 MODULE_ALIAS("platform:" DRV_NAME);
 MODULE_LICENSE("GPL v2");
 
+struct sp_priv {
+	spinlock_t ind_lock;
+};
+
 static u8 sp_read_reg8(const struct sja1000_priv *priv, int reg)
 {
-	return ioread8(priv->reg_base + reg);
+	struct sp_priv *sp = priv->priv;
+	unsigned long flags;
+	u8 val;
+
+	spin_lock_irqsave(&sp->ind_lock, flags);
+	iowrite8(reg, priv->reg_base);
+	val = ioread8(priv->reg_base + 0x20);
+	spin_unlock_irqrestore(&sp->ind_lock, flags);
+
+	return val;
 }
 
 static void sp_write_reg8(const struct sja1000_priv *priv, int reg, u8 val)
 {
-	iowrite8(val, priv->reg_base + reg);
+	struct sp_priv *sp = priv->priv;
+	unsigned long flags;
+
+	spin_lock_irqsave(&sp->ind_lock, flags);
+	iowrite8(reg, priv->reg_base);
+	iowrite8(val, (priv->reg_base + 0x20));
+	spin_unlock_irqrestore(&sp->ind_lock, flags);
 }
 
 static u8 sp_read_reg16(const struct sja1000_priv *priv, int reg)
@@ -73,6 +92,7 @@ static int sp_probe(struct platform_device *pdev)
 	void __iomem *addr;
 	struct net_device *dev;
 	struct sja1000_priv *priv;
+	struct sp_priv *sp;
 	struct resource *res_mem, *res_irq;
 	struct sja1000_platform_data *pdata;
 
@@ -102,12 +122,13 @@ static int sp_probe(struct platform_device *pdev)
 		goto exit_release;
 	}
 
-	dev = alloc_sja1000dev(0);
+	dev = alloc_sja1000dev(sizeof(struct sp_priv));
 	if (!dev) {
 		err = -ENOMEM;
 		goto exit_iounmap;
 	}
 	priv = netdev_priv(dev);
+	sp = priv->priv;
 
 	dev->irq = res_irq->start;
 	priv->irq_flags = res_irq->flags & IRQF_TRIGGER_MASK;
@@ -118,6 +139,7 @@ static int sp_probe(struct platform_device *pdev)
 	priv->can.clock.freq = pdata->osc_freq / 2;
 	priv->ocr = pdata->ocr;
 	priv->cdr = pdata->cdr;
+	spin_lock_init(&sp->ind_lock);
 
 	switch (res_mem->flags & IORESOURCE_MEM_TYPE_MASK) {
 	case IORESOURCE_MEM_32BIT:
-- 
1.8.3.1


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