openwrt/target/linux/bcm27xx/patches-5.4/950-0733-sc16is7xx-Fix-for-hardware-flow-control.patch
Álvaro Fernández Rojas f07e572f64 bcm27xx: import latest patches from the RPi foundation
bcm2708: boot tested on RPi B+ v1.2
bcm2709: boot tested on RPi 3B v1.2 and RPi 4B v1.1 4G
bcm2710: boot tested on RPi 3B v1.2
bcm2711: boot tested on RPi 4B v1.1 4G

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
2021-02-18 23:42:32 +01:00

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2.5 KiB
Diff

From 41ed4262b7398a3170399af81cf78cb8d7dd8b8d Mon Sep 17 00:00:00 2001
From: Phil Elwell <phil@raspberrypi.com>
Date: Wed, 13 May 2020 20:10:15 +0100
Subject: [PATCH] sc16is7xx: Fix for hardware flow control
The SC16IS7XX hardware flow control is mishandled by the driver in
a number of ways:
1. The set_baud method accidentally clears it when setting EFR bit.
2. Even though hardware flow control is enabled, it isn't indicated
back to the serial framework.
3. Applying the flow control clears the EFR bit.
4. The CTS support is not indicated in the return from
sc16is7xx_get_mctrl.
Address all of those issues using a mixture of patches found on the
linked pages.
See: https://github.com/raspberrypi/linux/issues/2542
See: https://www.spinics.net/lists/linux-serial/msg21794.html
Signed-off-by: Phil Elwell <phil@raspberrypi.com>
---
drivers/tty/serial/sc16is7xx.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
--- a/drivers/tty/serial/sc16is7xx.c
+++ b/drivers/tty/serial/sc16is7xx.c
@@ -523,8 +523,9 @@ static int sc16is7xx_set_baud(struct uar
/* Enable enhanced features */
regcache_cache_bypass(s->regmap, true);
- sc16is7xx_port_write(port, SC16IS7XX_EFR_REG,
- SC16IS7XX_EFR_ENABLE_BIT);
+ sc16is7xx_port_update(port, SC16IS7XX_EFR_REG,
+ SC16IS7XX_EFR_ENABLE_BIT,
+ SC16IS7XX_EFR_ENABLE_BIT);
regcache_cache_bypass(s->regmap, false);
/* Put LCR back to the normal mode */
@@ -846,7 +847,7 @@ static unsigned int sc16is7xx_get_mctrl(
/* DCD and DSR are not wired and CTS/RTS is handled automatically
* so just indicate DSR and CAR asserted
*/
- return TIOCM_DSR | TIOCM_CAR;
+ return TIOCM_DSR | TIOCM_CAR | TIOCM_RI | TIOCM_CTS;
}
static void sc16is7xx_set_mctrl(struct uart_port *port, unsigned int mctrl)
@@ -933,14 +934,19 @@ static void sc16is7xx_set_termios(struct
regcache_cache_bypass(s->regmap, true);
sc16is7xx_port_write(port, SC16IS7XX_XON1_REG, termios->c_cc[VSTART]);
sc16is7xx_port_write(port, SC16IS7XX_XOFF1_REG, termios->c_cc[VSTOP]);
- if (termios->c_cflag & CRTSCTS)
+ if (termios->c_cflag & CRTSCTS) {
flow |= SC16IS7XX_EFR_AUTOCTS_BIT |
SC16IS7XX_EFR_AUTORTS_BIT;
+ port->status |= UPSTAT_AUTOCTS;
+ };
if (termios->c_iflag & IXON)
flow |= SC16IS7XX_EFR_SWFLOW3_BIT;
if (termios->c_iflag & IXOFF)
flow |= SC16IS7XX_EFR_SWFLOW1_BIT;
+ /* Always set enable enhanced */
+ flow |= SC16IS7XX_EFR_ENABLE_BIT;
+
sc16is7xx_port_write(port, SC16IS7XX_EFR_REG, flow);
regcache_cache_bypass(s->regmap, false);