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Date: Mon, 9 Sep 2013 09:25:07 +0200
From: Benedikt Spranger <b.spranger@...utronix.de>
To: netdev@...r.kernel.org
Cc: Alexander Frank <Alexander.Frank@...rspaecher.com>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
Holger Dengler <dengler@...utronix.de>,
Benedikt Spranger <b.spranger@...utronix.de>
Subject: [PATCH 10/16] c_can: add 16bit align 32bit access functions
The FlexCard only allows 32bit access to DCAN registers, otherwise the
register value can be wraped up. Add a new helper function to access
registers 16bit aligned but 32bit access.
Signed-off-by: Benedikt Spranger <b.spranger@...utronix.de>
---
drivers/net/can/c_can/c_can.c | 1 +
drivers/net/can/c_can/c_can.h | 1 +
drivers/net/can/c_can/c_can_platform.c | 38 ++++++++++++++++++++++++++++++++--
3 files changed, 38 insertions(+), 2 deletions(-)
diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index c573399..46d741d 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -1305,6 +1305,7 @@ struct net_device *alloc_c_can_dev(void)
priv->can.ctrlmode_supported = CAN_CTRLMODE_LOOPBACK |
CAN_CTRLMODE_LISTENONLY |
CAN_CTRLMODE_BERR_REPORTING;
+ spin_lock_init(&priv->lock);
return dev;
}
diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
index 9f0eda8..beea437 100644
--- a/drivers/net/can/c_can/c_can.h
+++ b/drivers/net/can/c_can/c_can.h
@@ -175,6 +175,7 @@ struct c_can_priv {
u32 __iomem *raminit_ctrlreg;
unsigned int instance;
void (*raminit) (const struct c_can_priv *priv, bool enable);
+ spinlock_t lock;
};
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 43a3e3f..c6c1eb4 100644
--- a/drivers/net/can/c_can/c_can_platform.c
+++ b/drivers/net/can/c_can/c_can_platform.c
@@ -58,6 +58,40 @@ static void c_can_plat_write_reg_aligned_to_16bit(struct c_can_priv *priv,
writew(val, priv->base + priv->regs[index]);
}
+#define ALIGN_DOWN(p, a) ((typeof(p))round_down((unsigned long)(p), (a)))
+
+static u16 c_can_plat_read_16bit_align_32bit_access(struct c_can_priv *priv,
+ enum reg index)
+{
+ void *addr = priv->base + priv->regs[index];
+ u32 reg;
+ reg = readl(ALIGN_DOWN(addr, 4));
+
+ return IS_ALIGNED((unsigned long)addr, 4) ?
+ reg & 0xffff :
+ reg >> 16;
+}
+
+static void c_can_plat_write_16bit_align_32bit_access(struct c_can_priv *priv,
+ enum reg index, u16 val)
+{
+ unsigned long flags;
+ void *addr = priv->base + priv->regs[index];
+ u32 reg;
+
+ spin_lock_irqsave(&priv->lock, flags);
+ reg = readl(ALIGN_DOWN(addr, 4));
+ if (IS_ALIGNED((unsigned long)addr, 4)) {
+ reg &= 0xffff0000;
+ reg |= val;
+ } else {
+ reg &= 0xffff;
+ reg |= val << 16;
+ }
+ writel(reg, ALIGN_DOWN(addr, 4));
+ spin_unlock_irqrestore(&priv->lock, flags);
+}
+
static u16 c_can_plat_read_reg_aligned_to_32bit(struct c_can_priv *priv,
enum reg index)
{
@@ -317,8 +351,8 @@ static int c_can_plat_probe(struct platform_device *pdev)
case BOSCH_D_CAN_FLEXCARD:
priv->regs = reg_map_d_can;
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;
+ priv->read_reg = c_can_plat_read_16bit_align_32bit_access;
+ priv->write_reg = c_can_plat_write_16bit_align_32bit_access;
priv->instance = pdev->id;
res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
--
1.8.4.rc3
--
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