openwrt/target/linux/bcm27xx/patches-4.19/950-0422-w1-ds2408-reset-on-output_write-retry-with-readback.patch
Adrian Schmutzler 7d7aa2fd92 brcm2708: rename target to bcm27xx
This change makes the names of Broadcom targets consistent by using
the common notation based on SoC/CPU ID (which is used internally
anyway), bcmXXXX instead of brcmXXXX.
This is even used for target TITLE in make menuconfig already,
only the short target name used brcm so far.

Despite, since subtargets range from bcm2708 to bcm2711, it seems
appropriate to use bcm27xx instead of bcm2708 (again, as already done
for BOARDNAME).

This also renames the packages brcm2708-userland and brcm2708-gpu-fw.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>
Acked-by: Álvaro Fernández Rojas <noltari@gmail.com>
2020-02-14 14:10:51 +01:00

141 lines
4.2 KiB
Diff

From 714580d7c11f81afb5e08c71f79a03a1ed4ae44e Mon Sep 17 00:00:00 2001
From: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Date: Thu, 28 Mar 2019 12:41:11 -0400
Subject: [PATCH] w1: ds2408: reset on output_write retry with readback
commit 49695ac46861180baf2b2b92c62da8619b6bf28f upstream.
When we have success in 'Channel Access Write' but reading back latch
states fails, a write is retried without doing a proper slave reset.
This leads to protocol errors as the slave treats the next 'Channel
Access Write' as the continuation of previous command.
This commit is fixing this by making sure if the retry loop re-runs, a
reset is performed, whatever the failure (CONFIRM_BYTE or the read
back).
The loop was quite due for a cleanup and this change mandated it. By
isolating the CONFIG_W1_SLAVE_DS2408_READBACK case into it's own
function, we vastly reduce the visual and branching(runtime and
compile-time) noise.
Reported-by: Mariusz Bialonczyk <manio@skyboo.net>
Tested-by: Mariusz Bialonczyk <manio@skyboo.net>
Signed-off-by: Jean-Francois Dagenais <jeff.dagenais@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/w1/slaves/w1_ds2408.c | 76 ++++++++++++++++++-----------------
1 file changed, 39 insertions(+), 37 deletions(-)
--- a/drivers/w1/slaves/w1_ds2408.c
+++ b/drivers/w1/slaves/w1_ds2408.c
@@ -138,14 +138,37 @@ static ssize_t status_control_read(struc
W1_F29_REG_CONTROL_AND_STATUS, buf);
}
+#ifdef fCONFIG_W1_SLAVE_DS2408_READBACK
+static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)
+{
+ u8 w1_buf[3];
+
+ if (w1_reset_resume_command(sl->master))
+ return false;
+
+ w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
+ w1_buf[1] = W1_F29_REG_OUTPUT_LATCH_STATE;
+ w1_buf[2] = 0;
+
+ w1_write_block(sl->master, w1_buf, 3);
+
+ return (w1_read_8(sl->master) == expected);
+}
+#else
+static bool optional_read_back_valid(struct w1_slave *sl, u8 expected)
+{
+ return true;
+}
+#endif
+
static ssize_t output_write(struct file *filp, struct kobject *kobj,
struct bin_attribute *bin_attr, char *buf,
loff_t off, size_t count)
{
struct w1_slave *sl = kobj_to_w1_slave(kobj);
u8 w1_buf[3];
- u8 readBack;
unsigned int retries = W1_F29_RETRIES;
+ ssize_t bytes_written = -EIO;
if (count != 1 || off != 0)
return -EFAULT;
@@ -155,54 +178,33 @@ static ssize_t output_write(struct file
dev_dbg(&sl->dev, "mutex locked");
if (w1_reset_select_slave(sl))
- goto error;
+ goto out;
- while (retries--) {
+ do {
w1_buf[0] = W1_F29_FUNC_CHANN_ACCESS_WRITE;
w1_buf[1] = *buf;
w1_buf[2] = ~(*buf);
- w1_write_block(sl->master, w1_buf, 3);
- readBack = w1_read_8(sl->master);
+ w1_write_block(sl->master, w1_buf, 3);
- if (readBack != W1_F29_SUCCESS_CONFIRM_BYTE) {
- if (w1_reset_resume_command(sl->master))
- goto error;
- /* try again, the slave is ready for a command */
- continue;
+ if (w1_read_8(sl->master) == W1_F29_SUCCESS_CONFIRM_BYTE &&
+ optional_read_back_valid(sl, *buf)) {
+ bytes_written = 1;
+ goto out;
}
-#ifdef CONFIG_W1_SLAVE_DS2408_READBACK
- /* here the master could read another byte which
- would be the PIO reg (the actual pin logic state)
- since in this driver we don't know which pins are
- in and outs, there's no value to read the state and
- compare. with (*buf) so end this command abruptly: */
if (w1_reset_resume_command(sl->master))
- goto error;
+ goto out; /* unrecoverable error */
+ /* try again, the slave is ready for a command */
+ } while (--retries);
- /* go read back the output latches */
- /* (the direct effect of the write above) */
- w1_buf[0] = W1_F29_FUNC_READ_PIO_REGS;
- w1_buf[1] = W1_F29_REG_OUTPUT_LATCH_STATE;
- w1_buf[2] = 0;
- w1_write_block(sl->master, w1_buf, 3);
- /* read the result of the READ_PIO_REGS command */
- if (w1_read_8(sl->master) == *buf)
-#endif
- {
- /* success! */
- mutex_unlock(&sl->master->bus_mutex);
- dev_dbg(&sl->dev,
- "mutex unlocked, retries:%d", retries);
- return 1;
- }
- }
-error:
+out:
mutex_unlock(&sl->master->bus_mutex);
- dev_dbg(&sl->dev, "mutex unlocked in error, retries:%d", retries);
- return -EIO;
+ dev_dbg(&sl->dev, "%s, mutex unlocked retries:%d\n",
+ (bytes_written > 0) ? "succeeded" : "error", retries);
+
+ return bytes_written;
}