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Subject[PATCH v4 2/5] w1: ds1wm: make endian clean and use standard io memory accessors
Date
o Make endian clean, make HW-endianness configurable.

o Use ioread*, iowrite* instead of __raw_readb,__raw_writeb
to also use memory-barriers when accessing HW-registers.
We do not want reordering to happen here.

Both changes are tightly coupled, so I do them in one patch

Signed-off-by: Johannes Poehlmann <johannes.poehlmann@izt-labs.de>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
---
drivers/w1/masters/ds1wm.c | 60 ++++++++++++++++++++++++++++++++++++++++++++--
include/linux/mfd/ds1wm.h | 5 ++++
2 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/drivers/w1/masters/ds1wm.c b/drivers/w1/masters/ds1wm.c
index 401e53e..d15575d 100644
--- a/drivers/w1/masters/ds1wm.c
+++ b/drivers/w1/masters/ds1wm.c
@@ -96,6 +96,7 @@ static struct {
struct ds1wm_data {
void __iomem *map;
unsigned int bus_shift; /* # of shifts to calc register offsets */
+ bool is_hw_big_endian;
struct platform_device *pdev;
const struct mfd_cell *cell;
int irq;
@@ -115,12 +116,65 @@ struct ds1wm_data {
static inline void ds1wm_write_register(struct ds1wm_data *ds1wm_data, u32 reg,
u8 val)
{
- __raw_writeb(val, ds1wm_data->map + (reg << ds1wm_data->bus_shift));
+ if (ds1wm_data->is_hw_big_endian) {
+ switch (ds1wm_data->bus_shift) {
+ case 0:
+ iowrite8(val, ds1wm_data->map + (reg << 0));
+ break;
+ case 1:
+ iowrite16be((u16)val, ds1wm_data->map + (reg << 1));
+ break;
+ case 2:
+ iowrite32be((u32)val, ds1wm_data->map + (reg << 2));
+ break;
+ }
+ } else {
+ switch (ds1wm_data->bus_shift) {
+ case 0:
+ iowrite8(val, ds1wm_data->map + (reg << 0));
+ break;
+ case 1:
+ iowrite16((u16)val, ds1wm_data->map + (reg << 1));
+ break;
+ case 2:
+ iowrite32((u32)val, ds1wm_data->map + (reg << 2));
+ break;
+ }
+ }
}

static inline u8 ds1wm_read_register(struct ds1wm_data *ds1wm_data, u32 reg)
{
- return __raw_readb(ds1wm_data->map + (reg << ds1wm_data->bus_shift));
+ u32 val = 0;
+
+ if (ds1wm_data->is_hw_big_endian) {
+ switch (ds1wm_data->bus_shift) {
+ case 0:
+ val = ioread8(ds1wm_data->map + (reg << 0));
+ break;
+ case 1:
+ val = ioread16be(ds1wm_data->map + (reg << 1));
+ break;
+ case 2:
+ val = ioread32be(ds1wm_data->map + (reg << 2));
+ break;
+ }
+ } else {
+ switch (ds1wm_data->bus_shift) {
+ case 0:
+ val = ioread8(ds1wm_data->map + (reg << 0));
+ break;
+ case 1:
+ val = ioread16(ds1wm_data->map + (reg << 1));
+ break;
+ case 2:
+ val = ioread32(ds1wm_data->map + (reg << 2));
+ break;
+ }
+ }
+ dev_dbg(&ds1wm_data->pdev->dev,
+ "ds1wm_read_register reg: %d, 32 bit val:%x\n", reg, val);
+ return (u8)val;
}


@@ -499,6 +553,8 @@ static int ds1wm_probe(struct platform_device *pdev)
return -EINVAL;
}

+ ds1wm_data->is_hw_big_endian = plat->is_hw_big_endian;
+
res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
if (!res)
return -ENXIO;
diff --git a/include/linux/mfd/ds1wm.h b/include/linux/mfd/ds1wm.h
index 79a01e8..2227c6a 100644
--- a/include/linux/mfd/ds1wm.h
+++ b/include/linux/mfd/ds1wm.h
@@ -16,6 +16,11 @@ struct ds1wm_driver_data {
*/
unsigned int reset_recover_delay;

+ /* Say 1 here for big endian Hardware
+ * (only relevant with bus-shift > 0
+ */
+ bool is_hw_big_endian;
+
/* left shift of register number to get register address offsett.
* Only 0,1,2 allowed for 8,16 or 32 bit bus width respectively
*/
--
2.1.4
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