Dear Peter,
On 10/25/2013 08:02 AM, Peter Chen wrote:
According to Freescale imx28 Errata, "ENGR119653 USB: ARM to USB
register error issue", All USB register write operations must
use the ARM SWP instruction. So, we implement special hw_write
and hw_test_and_clear for imx28.
Discussion for it at below:
http://marc.info/?l=linux-usb&m=137996395529294&w=2
Signed-off-by: Peter Chen <peter.chen-KZfg59tc24xl57MIdRCFDg@xxxxxxxxxxxxxxxx>
---
Changes for v2:
- Rebase to latest usb-next tree
drivers/usb/chipidea/ci.h | 23 +++++++++++++++++++++++
drivers/usb/chipidea/core.c | 2 ++
drivers/usb/chipidea/host.c | 1 +
include/linux/usb/chipidea.h | 1 +
4 files changed, 27 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/chipidea/ci.h b/drivers/usb/chipidea/ci.h
index 1c94fc5..4eb61d0 100644
--- a/drivers/usb/chipidea/ci.h
+++ b/drivers/usb/chipidea/ci.h
@@ -173,6 +173,8 @@ struct ci_hdrc {
struct dentry *debugfs;
bool id_event;
bool b_sess_valid_event;
+ /* imx28 needs swp instruction for writing */
+ bool imx28_write_fix;
};
static inline struct ci_role_driver *ci_role(struct ci_hdrc *ci)
@@ -253,6 +255,13 @@ static inline u32 hw_read(struct ci_hdrc *ci, enum ci_hw_regs reg, u32 mask)
return ioread32(ci->hw_bank.regmap[reg]) & mask;
}
+#ifdef CONFIG_SOC_IMX28
+static inline void imx28_ci_writel(u32 val32, volatile u32 *addr)
+{
+ __asm__ ("swp %0, %0, [%1]" : : "r"(val32), "r"(addr));
+}
+#endif
+
/**
* hw_write: writes to a hw register
* @reg: register index
@@ -266,7 +275,14 @@ static inline void hw_write(struct ci_hdrc *ci, enum ci_hw_regs reg,
data = (ioread32(ci->hw_bank.regmap[reg]) & ~mask)
| (data & mask);
+#ifdef CONFIG_SOC_IMX28
+ if (ci->imx28_write_fix)
+ imx28_ci_writel(data, ci->hw_bank.regmap[reg]);
+ else
+ iowrite32(data, ci->hw_bank.regmap[reg]);
+#else
iowrite32(data, ci->hw_bank.regmap[reg]);
+#endif
}
/**
@@ -281,7 +297,14 @@ static inline u32 hw_test_and_clear(struct ci_hdrc *ci, enum ci_hw_regs reg,
{
u32 val = ioread32(ci->hw_bank.regmap[reg]) & mask;
+#ifdef CONFIG_SOC_IMX28
+ if (ci->imx28_write_fix)
+ imx28_ci_writel(val, ci->hw_bank.regmap[reg]);
+ else
+ iowrite32(val, ci->hw_bank.regmap[reg]);
+#else
iowrite32(val, ci->hw_bank.regmap[reg]);
+#endif
return val;
}
Can't we remove the #ifdefs CONFIG_SOC_IMX28 all around?
The check is done on the new flag ci->imx28_write_fix which exists for all platforms,
isn't it?.
Best regards,
--
Héctor Palacios
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