mirror of
https://github.com/openwrt/openwrt.git
synced 2024-12-21 22:47:56 +00:00
8c405cdccc
The patches were generated from the RPi repo with the following command: git format-patch v6.6.34..rpi-6.1.y Some patches needed rebasing and, as usual, the applied and reverted, wireless drivers, Github workflows, READMEs and defconfigs patches were removed. Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
148 lines
4.5 KiB
Diff
148 lines
4.5 KiB
Diff
From b039a10b277af6aeb245e3b791e2dd4ab161698c Mon Sep 17 00:00:00 2001
|
|
From: Jonathan Bell <jonathan@raspberrypi.com>
|
|
Date: Thu, 11 Jan 2024 16:33:22 +0000
|
|
Subject: [PATCH 0849/1085] drivers: w1-gpio: add flag to force read-polling
|
|
while delaying
|
|
|
|
On Pi 5, the link to RP1 will bounce in and out of L1 depending on
|
|
inactivity timers at both the RC and EP end. Unfortunately for
|
|
bitbashing 1-wire, this means that on an otherwise idle Pi 5 many of the
|
|
reads/writes to GPIO registers are delayed by up to 8us which causes
|
|
mis-sampling of read data and trashes write bits.
|
|
|
|
By issuing dummy reads at a rate greater than the link inactivity
|
|
timeout while spinning on a delay, PCIe stays in L0 which does not incur
|
|
additional latency.
|
|
|
|
Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
|
|
---
|
|
drivers/w1/masters/w1-gpio.c | 3 +++
|
|
drivers/w1/w1_io.c | 37 ++++++++++++++++++++++++------------
|
|
include/linux/w1.h | 5 +++++
|
|
3 files changed, 33 insertions(+), 12 deletions(-)
|
|
|
|
--- a/drivers/w1/masters/w1-gpio.c
|
|
+++ b/drivers/w1/masters/w1-gpio.c
|
|
@@ -90,6 +90,9 @@ static int w1_gpio_probe(struct platform
|
|
if (of_property_present(np, "linux,open-drain"))
|
|
gflags = GPIOD_OUT_LOW;
|
|
|
|
+ if (of_property_present(np, "raspberrypi,delay-needs-poll"))
|
|
+ master->delay_needs_poll = true;
|
|
+
|
|
pdev->dev.platform_data = pdata;
|
|
}
|
|
pdata = dev_get_platdata(dev);
|
|
--- a/drivers/w1/w1_io.c
|
|
+++ b/drivers/w1/w1_io.c
|
|
@@ -6,6 +6,7 @@
|
|
#include <asm/io.h>
|
|
|
|
#include <linux/delay.h>
|
|
+#include <linux/ktime.h>
|
|
#include <linux/moduleparam.h>
|
|
#include <linux/module.h>
|
|
|
|
@@ -36,9 +37,21 @@ static u8 w1_crc8_table[] = {
|
|
116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53
|
|
};
|
|
|
|
-static void w1_delay(unsigned long tm)
|
|
+static void w1_delay(struct w1_master *dev, unsigned long tm)
|
|
{
|
|
- udelay(tm * w1_delay_parm);
|
|
+ ktime_t start, delta;
|
|
+
|
|
+ if (!dev->bus_master->delay_needs_poll) {
|
|
+ udelay(tm * w1_delay_parm);
|
|
+ return;
|
|
+ }
|
|
+
|
|
+ start = ktime_get();
|
|
+ delta = ktime_add(start, ns_to_ktime(1000 * tm * w1_delay_parm));
|
|
+ do {
|
|
+ dev->bus_master->read_bit(dev->bus_master->data);
|
|
+ udelay(1);
|
|
+ } while (ktime_before(ktime_get(), delta));
|
|
}
|
|
|
|
static void w1_write_bit(struct w1_master *dev, int bit);
|
|
@@ -77,14 +90,14 @@ static void w1_write_bit(struct w1_maste
|
|
|
|
if (bit) {
|
|
dev->bus_master->write_bit(dev->bus_master->data, 0);
|
|
- w1_delay(6);
|
|
+ w1_delay(dev, 6);
|
|
dev->bus_master->write_bit(dev->bus_master->data, 1);
|
|
- w1_delay(64);
|
|
+ w1_delay(dev, 64);
|
|
} else {
|
|
dev->bus_master->write_bit(dev->bus_master->data, 0);
|
|
- w1_delay(60);
|
|
+ w1_delay(dev, 60);
|
|
dev->bus_master->write_bit(dev->bus_master->data, 1);
|
|
- w1_delay(10);
|
|
+ w1_delay(dev, 10);
|
|
}
|
|
|
|
if(w1_disable_irqs) local_irq_restore(flags);
|
|
@@ -164,14 +177,14 @@ static u8 w1_read_bit(struct w1_master *
|
|
/* sample timing is critical here */
|
|
local_irq_save(flags);
|
|
dev->bus_master->write_bit(dev->bus_master->data, 0);
|
|
- w1_delay(6);
|
|
+ w1_delay(dev, 6);
|
|
dev->bus_master->write_bit(dev->bus_master->data, 1);
|
|
- w1_delay(9);
|
|
+ w1_delay(dev, 9);
|
|
|
|
result = dev->bus_master->read_bit(dev->bus_master->data);
|
|
local_irq_restore(flags);
|
|
|
|
- w1_delay(55);
|
|
+ w1_delay(dev, 55);
|
|
|
|
return result & 0x1;
|
|
}
|
|
@@ -333,16 +346,16 @@ int w1_reset_bus(struct w1_master *dev)
|
|
* cpu for such a short amount of time AND get it back in
|
|
* the maximum amount of time.
|
|
*/
|
|
- w1_delay(500);
|
|
+ w1_delay(dev, 500);
|
|
dev->bus_master->write_bit(dev->bus_master->data, 1);
|
|
- w1_delay(70);
|
|
+ w1_delay(dev, 70);
|
|
|
|
result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1;
|
|
/* minimum 70 (above) + 430 = 500 us
|
|
* There aren't any timing requirements between a reset and
|
|
* the following transactions. Sleeping is safe here.
|
|
*/
|
|
- /* w1_delay(430); min required time */
|
|
+ /* w1_delay(dev, 430); min required time */
|
|
msleep(1);
|
|
}
|
|
|
|
--- a/include/linux/w1.h
|
|
+++ b/include/linux/w1.h
|
|
@@ -121,6 +121,9 @@ typedef void (*w1_slave_found_callback)(
|
|
* @dev_id: Optional device id string, which w1 slaves could use for
|
|
* creating names, which then give a connection to the w1 master
|
|
*
|
|
+ * @delay_needs_poll: work around jitter introduced with GPIO controllers
|
|
+ * accessed over PCIe (RP1)
|
|
+ *
|
|
* Note: read_bit and write_bit are very low level functions and should only
|
|
* be used with hardware that doesn't really support 1-wire operations,
|
|
* like a parallel/serial port.
|
|
@@ -155,6 +158,8 @@ struct w1_bus_master {
|
|
u8, w1_slave_found_callback);
|
|
|
|
char *dev_id;
|
|
+
|
|
+ bool delay_needs_poll;
|
|
};
|
|
|
|
/**
|