5.4-stable review patch. If anyone has any objections, please let me know.
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From: Hugo Villeneuve hvilleneuve@dimonoff.com
[ Upstream commit 2861ed4d6e6d1a2c9de9bf5b0abd996c2dc673d0 ]
The sc16is7xx_config_rs485() function is called only for the second port (index 1, channel B), causing initialization problems for the first port.
For the sc16is7xx driver, port->membase and port->mapbase are not set, and their default values are 0. And we set port->iobase to the device index. This means that when the first device is registered using the uart_add_one_port() function, the following values will be in the port structure: port->membase = 0 port->mapbase = 0 port->iobase = 0
Therefore, the function uart_configure_port() in serial_core.c will exit early because of the following check: /* * If there isn't a port here, don't do anything further. */ if (!port->iobase && !port->mapbase && !port->membase) return;
Typically, I2C and SPI drivers do not set port->membase and port->mapbase.
The max310x driver sets port->membase to ~0 (all ones). By implementing the same change in this driver, uart_configure_port() is now correctly executed for all ports.
Fixes: dfeae619d781 ("serial: sc16is7xx") Cc: stable@vger.kernel.org Signed-off-by: Hugo Villeneuve hvilleneuve@dimonoff.com Reviewed-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Reviewed-by: Lech Perczak lech.perczak@camlingroup.com Tested-by: Lech Perczak lech.perczak@camlingroup.com Link: https://lore.kernel.org/r/20230807214556.540627-2-hugo@hugovil.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/tty/serial/sc16is7xx.c | 6 ++++++ 1 file changed, 6 insertions(+)
diff --git a/drivers/tty/serial/sc16is7xx.c b/drivers/tty/serial/sc16is7xx.c index 9b68725d4e9ba..091cf5fe90304 100644 --- a/drivers/tty/serial/sc16is7xx.c +++ b/drivers/tty/serial/sc16is7xx.c @@ -1271,6 +1271,12 @@ static int sc16is7xx_probe(struct device *dev, s->p[i].port.fifosize = SC16IS7XX_FIFO_SIZE; s->p[i].port.flags = UPF_FIXED_TYPE | UPF_LOW_LATENCY; s->p[i].port.iobase = i; + /* + * Use all ones as membase to make sure uart_configure_port() in + * serial_core.c does not abort for SPI/I2C devices where the + * membase address is not applicable. + */ + s->p[i].port.membase = (void __iomem *)~0; s->p[i].port.iotype = UPIO_PORT; s->p[i].port.uartclk = freq; s->p[i].port.rs485_config = sc16is7xx_config_rs485;