diff options
Diffstat (limited to 'target/linux/brcm2708/patches-4.19/950-0796-tty-amba-pl011-Add-un-throttle-support.patch')
| -rw-r--r-- | target/linux/brcm2708/patches-4.19/950-0796-tty-amba-pl011-Add-un-throttle-support.patch | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/target/linux/brcm2708/patches-4.19/950-0796-tty-amba-pl011-Add-un-throttle-support.patch b/target/linux/brcm2708/patches-4.19/950-0796-tty-amba-pl011-Add-un-throttle-support.patch new file mode 100644 index 0000000000..0ab6cf2fe9 --- /dev/null +++ b/target/linux/brcm2708/patches-4.19/950-0796-tty-amba-pl011-Add-un-throttle-support.patch @@ -0,0 +1,61 @@ +From d4f4b57c667141ca98711cfcb30ae2b8deb1a034 Mon Sep 17 00:00:00 2001 +From: Phil Elwell <phil@raspberrypi.org> +Date: Fri, 24 Jan 2020 11:38:28 +0000 +Subject: [PATCH] tty: amba-pl011: Add un/throttle support + +The PL011 driver lacks throttle and unthrottle methods. As a result, +sending more data to the Pi than it can immediately sink while CRTSCTS +is enabled causes a NULL pointer to be followed. + +Add a throttle handler that disables the RX interrupts, and an +unthrottle handler that reenables them. + +Signed-off-by: Phil Elwell <phil@raspberrypi.org> +--- + drivers/tty/serial/amba-pl011.c | 28 ++++++++++++++++++++++++++++ + 1 file changed, 28 insertions(+) + +--- a/drivers/tty/serial/amba-pl011.c ++++ b/drivers/tty/serial/amba-pl011.c +@@ -1323,6 +1323,32 @@ static void pl011_start_tx(struct uart_p + pl011_start_tx_pio(uap); + } + ++static void pl011_throttle(struct uart_port *port) ++{ ++ struct uart_amba_port *uap = ++ container_of(port, struct uart_amba_port, port); ++ unsigned long flags; ++ ++ spin_lock_irqsave(&uap->port.lock, flags); ++ uap->im &= ~(UART011_RTIM | UART011_RXIM); ++ pl011_write(uap->im, uap, REG_IMSC); ++ spin_unlock_irqrestore(&uap->port.lock, flags); ++} ++ ++static void pl011_unthrottle(struct uart_port *port) ++{ ++ struct uart_amba_port *uap = ++ container_of(port, struct uart_amba_port, port); ++ unsigned long flags; ++ ++ spin_lock_irqsave(&uap->port.lock, flags); ++ uap->im |= UART011_RTIM; ++ if (!pl011_dma_rx_running(uap)) ++ uap->im |= UART011_RXIM; ++ pl011_write(uap->im, uap, REG_IMSC); ++ spin_unlock_irqrestore(&uap->port.lock, flags); ++} ++ + static void pl011_stop_rx(struct uart_port *port) + { + struct uart_amba_port *uap = +@@ -2165,6 +2191,8 @@ static const struct uart_ops amba_pl011_ + .stop_tx = pl011_stop_tx, + .start_tx = pl011_start_tx, + .stop_rx = pl011_stop_rx, ++ .throttle = pl011_throttle, ++ .unthrottle = pl011_unthrottle, + .enable_ms = pl011_enable_ms, + .break_ctl = pl011_break_ctl, + .startup = pl011_startup, |