diff options
author | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2019-12-18 22:52:20 +0100 |
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committer | Marcel Ziswiler <marcel.ziswiler@toradex.com> | 2019-12-18 22:52:20 +0100 |
commit | 1ddf624b0b268fdc0b80b1de618b98f8d117afea (patch) | |
tree | 3d3218332bcb34cb0afa01d6ad996058a3dbcb77 /drivers/tty/serial/sc16is7xx.c | |
parent | 6b774eec1f9d3064e9b33634dfa99d5666d0a73a (diff) | |
parent | bfb9e5c03076a446b1f4f6a523ddc8d723c907a6 (diff) |
Merge tag 'v4.14.159' into 4.14-2.0.x-imx
This is the 4.14.159 stable release
Conflicts:
arch/arm/Kconfig.debug
arch/arm/boot/dts/imx7s.dtsi
arch/arm/mach-imx/cpuidle-imx6sx.c
drivers/crypto/caam/caamalg.c
drivers/crypto/mxs-dcp.c
drivers/dma/imx-sdma.c
drivers/input/keyboard/imx_keypad.c
drivers/net/can/flexcan.c
drivers/net/can/rx-offload.c
drivers/net/wireless/ath/ath10k/pci.c
drivers/pci/dwc/pci-imx6.c
drivers/spi/spi-fsl-lpspi.c
drivers/usb/dwc3/gadget.c
Diffstat (limited to 'drivers/tty/serial/sc16is7xx.c')
-rw-r--r-- | drivers/tty/serial/sc16is7xx.c | 28 |
1 files changed, 28 insertions, 0 deletions
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index e48523da47ac..c1655aba131f 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -333,6 +333,7 @@ struct sc16is7xx_port { struct kthread_worker kworker; struct task_struct *kworker_task; struct kthread_work irq_work; + struct mutex efr_lock; struct sc16is7xx_one p[0]; }; @@ -504,6 +505,21 @@ static int sc16is7xx_set_baud(struct uart_port *port, int baud) div /= 4; } + /* In an amazing feat of design, the Enhanced Features Register shares + * the address of the Interrupt Identification Register, and is + * switched in by writing a magic value (0xbf) to the Line Control + * Register. Any interrupt firing during this time will see the EFR + * where it expects the IIR to be, leading to "Unexpected interrupt" + * messages. + * + * Prevent this possibility by claiming a mutex while accessing the + * EFR, and claiming the same mutex from within the interrupt handler. + * This is similar to disabling the interrupt, but that doesn't work + * because the bulk of the interrupt processing is run as a workqueue + * job in thread context. + */ + mutex_lock(&s->efr_lock); + lcr = sc16is7xx_port_read(port, SC16IS7XX_LCR_REG); /* Open the LCR divisors for configuration */ @@ -519,6 +535,8 @@ static int sc16is7xx_set_baud(struct uart_port *port, int baud) /* Put LCR back to the normal mode */ sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr); + mutex_unlock(&s->efr_lock); + sc16is7xx_port_update(port, SC16IS7XX_MCR_REG, SC16IS7XX_MCR_CLKSEL_BIT, prescaler); @@ -701,6 +719,8 @@ static void sc16is7xx_ist(struct kthread_work *ws) { struct sc16is7xx_port *s = to_sc16is7xx_port(ws, irq_work); + mutex_lock(&s->efr_lock); + while (1) { bool keep_polling = false; int i; @@ -710,6 +730,8 @@ static void sc16is7xx_ist(struct kthread_work *ws) if (!keep_polling) break; } + + mutex_unlock(&s->efr_lock); } static irqreturn_t sc16is7xx_irq(int irq, void *dev_id) @@ -904,6 +926,9 @@ static void sc16is7xx_set_termios(struct uart_port *port, if (!(termios->c_cflag & CREAD)) port->ignore_status_mask |= SC16IS7XX_LSR_BRK_ERROR_MASK; + /* As above, claim the mutex while accessing the EFR. */ + mutex_lock(&s->efr_lock); + sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, SC16IS7XX_LCR_CONF_MODE_B); @@ -925,6 +950,8 @@ static void sc16is7xx_set_termios(struct uart_port *port, /* Update LCR register */ sc16is7xx_port_write(port, SC16IS7XX_LCR_REG, lcr); + mutex_unlock(&s->efr_lock); + /* Get baud rate generator configuration */ baud = uart_get_baud_rate(port, termios, old, port->uartclk / 16 / 4 / 0xffff, @@ -1187,6 +1214,7 @@ static int sc16is7xx_probe(struct device *dev, s->regmap = regmap; s->devtype = devtype; dev_set_drvdata(dev, s); + mutex_init(&s->efr_lock); kthread_init_worker(&s->kworker); kthread_init_work(&s->irq_work, sc16is7xx_ist); |