[Resend PATCH 06/10] i2c-octeon: Flush TWSI writes with readback

From: Jan Glauber
Date: Mon Feb 29 2016 - 08:48:43 EST


From: Peter Swain <pswain@xxxxxxxxxx>

Signed-off-by: Peter Swain <pswain@xxxxxxxxxx>
Signed-off-by: Jan Glauber <jglauber@xxxxxxxxxx>
Acked-by: David Daney <ddaney@xxxxxxxxxxxxxxxxxx>
---
drivers/i2c/busses/i2c-octeon.c | 19 ++++++++++++-------
1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/i2c/busses/i2c-octeon.c b/drivers/i2c/busses/i2c-octeon.c
index 0b28d8c..bb15a9c 100644
--- a/drivers/i2c/busses/i2c-octeon.c
+++ b/drivers/i2c/busses/i2c-octeon.c
@@ -130,6 +130,12 @@ static int timeout = 2;
module_param(timeout, int, 0444);
MODULE_PARM_DESC(timeout, "Low-level device timeout (ms)");

+static void writeqflush(u64 val, void __iomem *addr)
+{
+ __raw_writeq(val, addr);
+ __raw_readq(addr); /* wait for write to land */
+}
+
/**
* octeon_i2c_write_sw - write an I2C core register
* @i2c: The struct octeon_i2c
@@ -190,8 +196,7 @@ static u8 octeon_i2c_read_sw(struct octeon_i2c *i2c, u64 eop_reg)
*/
static void octeon_i2c_write_int(struct octeon_i2c *i2c, u64 data)
{
- __raw_writeq(data, i2c->twsi_base + TWSI_INT);
- __raw_readq(i2c->twsi_base + TWSI_INT);
+ writeqflush(data, i2c->twsi_base + TWSI_INT);
}

/**
@@ -797,10 +802,10 @@ static int octeon_i2c_simple_write(struct octeon_i2c *i2c, struct i2c_msg *msgs)

for (i = 0; i < msgs[0].len - 4 && i < 4; i++, j--)
ext |= (u64) msgs[0].buf[j] << (8 * i);
- __raw_writeq(ext, i2c->twsi_base + SW_TWSI_EXT);
+ writeqflush(ext, i2c->twsi_base + SW_TWSI_EXT);
}

- __raw_writeq(cmd, i2c->twsi_base + SW_TWSI);
+ writeqflush(cmd, i2c->twsi_base + SW_TWSI);

ret = octeon_i2c_hlc_wait(i2c);
if (ret)
@@ -846,7 +851,7 @@ static int octeon_i2c_ia_read(struct octeon_i2c *i2c, struct i2c_msg *msgs)
cmd |= (u64) msgs[0].buf[0] << SW_TWSI_IA_SHIFT;

octeon_i2c_hlc_int_clear(i2c);
- __raw_writeq(cmd, i2c->twsi_base + SW_TWSI);
+ writeqflush(cmd, i2c->twsi_base + SW_TWSI);

ret = octeon_i2c_hlc_wait(i2c);
if (ret)
@@ -906,10 +911,10 @@ static int octeon_i2c_ia_write(struct octeon_i2c *i2c, struct i2c_msg *msgs)
set_ext = true;
}
if (set_ext)
- __raw_writeq(ext, i2c->twsi_base + SW_TWSI_EXT);
+ writeqflush(ext, i2c->twsi_base + SW_TWSI_EXT);

octeon_i2c_hlc_int_clear(i2c);
- __raw_writeq(cmd, i2c->twsi_base + SW_TWSI);
+ writeqflush(cmd, i2c->twsi_base + SW_TWSI);

ret = octeon_i2c_hlc_wait(i2c);
if (ret)
--
1.9.1