From: Dean Luick <dean.luick@xxxxxxxxx>
Change the TWSI reset function so it will stop the reset
once the lines are in an expected state.
Reviewed-by: Easwar Hariharan <easwar.hariharan@xxxxxxxxx>
Reviewed-by: Dean Luick <dean.luick@xxxxxxxxx>
Signed-off-by: Pablo Cacho <pablo.cacho@xxxxxxxxx>
Signed-off-by: Jubin John <jubin.john@xxxxxxxxx>
---
drivers/staging/rdma/hfi1/qsfp.c | 10 ++----
drivers/staging/rdma/hfi1/twsi.c | 64 +++++++++++++++++---------------------
drivers/staging/rdma/hfi1/twsi.h | 7 ++--
3 files changed, 36 insertions(+), 45 deletions(-)
diff --git a/drivers/staging/rdma/hfi1/qsfp.c b/drivers/staging/rdma/hfi1/qsfp.c
index 0e1a492..c9d1e64 100644
--- a/drivers/staging/rdma/hfi1/qsfp.c
+++ b/drivers/staging/rdma/hfi1/qsfp.c
@@ -5,7 +5,7 @@
*
* GPL LICENSE SUMMARY
*
- * Copyright(c) 2015 Intel Corporation.
+ * Copyright(c) 2015, 2016 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
@@ -18,7 +18,7 @@
*
* BSD LICENSE
*
- * Copyright(c) 2015 Intel Corporation.
+ * Copyright(c) 2015, 2016 Intel Corporation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -106,7 +106,6 @@ int i2c_write(struct hfi1_pportdata *ppd, u32 target, int i2c_addr, int offset,
if (ret) {
hfi1_dev_porterr(ppd->dd, ppd->port,
"I2C write interface reset failed\n");
- ret = -EIO;
goto done;
}
@@ -179,7 +178,6 @@ int i2c_read(struct hfi1_pportdata *ppd, u32 target, int i2c_addr, int offset,
if (ret) {
hfi1_dev_porterr(ppd->dd, ppd->port,
"I2C read interface reset failed\n");
- ret = -EIO;
goto done;
}
@@ -213,7 +211,7 @@ int qsfp_write(struct hfi1_pportdata *ppd, u32 target, int addr, void *bp,
hfi1_dev_porterr(ppd->dd, ppd->port,
"QSFP write interface reset failed\n");
mutex_unlock(&ppd->dd->qsfp_i2c_mutex);
- return -EIO;
+ return ret;
}
while (count < len) {
@@ -279,7 +277,7 @@ int qsfp_read(struct hfi1_pportdata *ppd, u32 target, int addr, void *bp,
hfi1_dev_porterr(ppd->dd, ppd->port,
"QSFP read interface reset failed\n");
mutex_unlock(&ppd->dd->qsfp_i2c_mutex);
- return -EIO;
+ return ret;
}
while (count < len) {
diff --git a/drivers/staging/rdma/hfi1/twsi.c b/drivers/staging/rdma/hfi1/twsi.c
index 7c579b3..d7dfdd2 100644
--- a/drivers/staging/rdma/hfi1/twsi.c
+++ b/drivers/staging/rdma/hfi1/twsi.c
@@ -5,7 +5,7 @@
*
* GPL LICENSE SUMMARY
*
- * Copyright(c) 2015 Intel Corporation.
+ * Copyright(c) 2015, 2016 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
@@ -18,7 +18,7 @@
*
* BSD LICENSE
*
- * Copyright(c) 2015 Intel Corporation.
+ * Copyright(c) 2015, 2016 Intel Corporation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -136,6 +136,19 @@ static void scl_out(struct hfi1_devdata *dd, u32 target, u8 bit)
i2c_wait_for_writes(dd, target);
}
+static u8 scl_in(struct hfi1_devdata *dd, u32 target, int wait)
+{
+ u32 read_val, mask;
+
+ mask = QSFP_HFI0_I2CCLK;
+ /* SCL is meant to be bare-drain, so never set "OUT", just DIR */
+ hfi1_gpio_mod(dd, target, 0, 0, mask);
+ read_val = hfi1_gpio_mod(dd, target, 0, 0, 0);
+ if (wait)
+ i2c_wait_for_writes(dd, target);
+ return (read_val & mask) >> GPIO_SCL_NUM;
+}
+
static void sda_out(struct hfi1_devdata *dd, u32 target, u8 bit)
{
u32 mask;
@@ -274,13 +287,12 @@ static void stop_cmd(struct hfi1_devdata *dd, u32 target)
/**
* hfi1_twsi_reset - reset I2C communication
* @dd: the hfi1_ib device
+ * returns 0 if ok, -EIO on error
*/
-
int hfi1_twsi_reset(struct hfi1_devdata *dd, u32 target)
{
int clock_cycles_left = 9;
- int was_high = 0;
- u32 pins, mask;
+ u32 mask;
/* Both SCL and SDA should be high. If not, there
* is something wrong.
@@ -294,43 +306,23 @@ int hfi1_twsi_reset(struct hfi1_devdata *dd, u32 target)
*/
hfi1_gpio_mod(dd, target, 0, 0, mask);
- /*
- * Clock nine times to get all listeners into a sane state.
- * If SDA does not go high at any point, we are wedged.
- * One vendor recommends then issuing START followed by STOP.
- * we cannot use our "normal" functions to do that, because
- * if SCL drops between them, another vendor's part will
- * wedge, dropping SDA and keeping it low forever, at the end of
- * the next transaction (even if it was not the device addressed).
- * So our START and STOP take place with SCL held high.
+ /* Check if SCL is low, if it is low then we have a slave device
+ * misbehaving and there is not much we can do.
+ */
+ if (!scl_in(dd, target, 0))
+ return -EIO;
+
+ /* Check if SDA is low, if it is low then we have to clock SDA
+ * up to 9 times for the device to release the bus
*/
while (clock_cycles_left--) {
+ if (sda_in(dd, target, 0))
+ return 0;
scl_out(dd, target, 0);
scl_out(dd, target, 1);
- /* Note if SDA is high, but keep clocking to sync slave */
- was_high |= sda_in(dd, target, 0);
- }
-
- if (was_high) {
- /*
- * We saw a high, which we hope means the slave is sync'd.
- * Issue START, STOP, pause for T_BUF.
- */
-
- pins = hfi1_gpio_mod(dd, target, 0, 0, 0);
- if ((pins & mask) != mask)
- dd_dev_err(dd, "GPIO pins not at rest: %d\n",
- pins & mask);
- /* Drop SDA to issue START */
- udelay(1); /* Guarantee .6 uSec setup */
- sda_out(dd, target, 0);
- udelay(1); /* Guarantee .6 uSec hold */
- /* At this point, SCL is high, SDA low. Raise SDA for STOP */
- sda_out(dd, target, 1);
- udelay(TWSI_BUF_WAIT_USEC);
}
- return !was_high;
+ return -EIO;
}
#define HFI1_TWSI_START 0x100
diff --git a/drivers/staging/rdma/hfi1/twsi.h b/drivers/staging/rdma/hfi1/twsi.h
index 5907e02..6cb30e5 100644
--- a/drivers/staging/rdma/hfi1/twsi.h
+++ b/drivers/staging/rdma/hfi1/twsi.h
@@ -7,7 +7,7 @@
*
* GPL LICENSE SUMMARY
*
- * Copyright(c) 2015 Intel Corporation.
+ * Copyright(c) 2015, 2016 Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
@@ -20,7 +20,7 @@
*
* BSD LICENSE
*
- * Copyright(c) 2015 Intel Corporation.
+ * Copyright(c) 2015, 2016 Intel Corporation.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
@@ -54,8 +54,9 @@
struct hfi1_devdata;
-/* Bit position of SDA pin in ASIC_QSFP* registers */
+/* Bit position of SDA/SCL pins in ASIC_QSFP* registers */
#define GPIO_SDA_NUM 1
+#define GPIO_SCL_NUM 0
/* these functions must be called with qsfp_lock held */
int hfi1_twsi_reset(struct hfi1_devdata *dd, u32 target);
--
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