From: Sergey Organov <[email protected]> commit d45fb2e430e54fac6af3cabb39c36171c4bf3f52 from upstream.
We perform soft reset in 2 places, slightly differently for no sufficient reasons, so move more generic variant to a function, and re-use the code. Out of 2 repeat counters, 10 and 100, select 10, as the code works at interrupts disabled, and in practice the reset happens immediately. Signed-off-by: Sergey Organov <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Greg Kroah-Hartman <[email protected]> Signed-off-by: Xiaolei Wang <[email protected]> --- drivers/tty/serial/imx.c | 73 ++++++++++++++++++++-------------------- 1 file changed, 37 insertions(+), 36 deletions(-) diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 77a3649f80ba..8b32d8e549dc 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -413,6 +413,39 @@ static void imx_uart_disable_loopback_rs485(struct imx_port *sport) imx_uart_writel(sport, uts, imx_uart_uts_reg(sport)); } +/* called with port.lock taken and irqs off */ +static void imx_uart_soft_reset(struct imx_port *sport) +{ + int i = 10; + u32 ucr2, ubir, ubmr, uts; + + /* + * According to the Reference Manual description of the UART SRST bit: + * + * "Reset the transmit and receive state machines, + * all FIFOs and register USR1, USR2, UBIR, UBMR, UBRC, URXD, UTXD + * and UTS[6-3]". + * + * We don't need to restore the old values from USR1, USR2, URXD and + * UTXD. UBRC is read only, so only save/restore the other three + * registers. + */ + ubir = imx_uart_readl(sport, UBIR); + ubmr = imx_uart_readl(sport, UBMR); + uts = imx_uart_readl(sport, IMX21_UTS); + + ucr2 = imx_uart_readl(sport, UCR2); + imx_uart_writel(sport, ucr2 & ~UCR2_SRST, UCR2); + + while (!(imx_uart_readl(sport, UCR2) & UCR2_SRST) && (--i > 0)) + udelay(1); + + /* Restore the registers */ + imx_uart_writel(sport, ubir, UBIR); + imx_uart_writel(sport, ubmr, UBMR); + imx_uart_writel(sport, uts, IMX21_UTS); +} + /* called with port.lock taken and irqs off */ static void imx_uart_start_rx(struct uart_port *port) { @@ -1420,7 +1453,7 @@ static int imx_uart_startup(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; struct tty_port *tty_port = &sport->port.state->port; - int retval, i; + int retval; unsigned long flags; int dma_is_inited = 0; u32 ucr1, ucr2, ucr3, ucr4; @@ -1459,15 +1492,9 @@ static int imx_uart_startup(struct uart_port *port) dma_is_inited = 1; spin_lock_irqsave(&sport->port.lock, flags); - /* Reset fifo's and state machines */ - i = 100; - ucr2 = imx_uart_readl(sport, UCR2); - ucr2 &= ~UCR2_SRST; - imx_uart_writel(sport, ucr2, UCR2); - - while (!(imx_uart_readl(sport, UCR2) & UCR2_SRST) && (--i > 0)) - udelay(1); + /* Reset fifo's and state machines */ + imx_uart_soft_reset(sport); /* * Finally, clear and enable interrupts @@ -1620,8 +1647,6 @@ static void imx_uart_flush_buffer(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; struct scatterlist *sgl = &sport->tx_sgl[0]; - u32 ucr2; - int i = 100, ubir, ubmr, uts; if (!sport->dma_chan_tx) return; @@ -1639,32 +1664,8 @@ static void imx_uart_flush_buffer(struct uart_port *port) sport->dma_is_txing = 0; } - /* - * According to the Reference Manual description of the UART SRST bit: - * - * "Reset the transmit and receive state machines, - * all FIFOs and register USR1, USR2, UBIR, UBMR, UBRC, URXD, UTXD - * and UTS[6-3]". - * - * We don't need to restore the old values from USR1, USR2, URXD and - * UTXD. UBRC is read only, so only save/restore the other three - * registers. - */ - ubir = imx_uart_readl(sport, UBIR); - ubmr = imx_uart_readl(sport, UBMR); - uts = imx_uart_readl(sport, IMX21_UTS); - - ucr2 = imx_uart_readl(sport, UCR2); - ucr2 &= ~UCR2_SRST; - imx_uart_writel(sport, ucr2, UCR2); + imx_uart_soft_reset(sport); - while (!(imx_uart_readl(sport, UCR2) & UCR2_SRST) && (--i > 0)) - udelay(1); - - /* Restore the registers */ - imx_uart_writel(sport, ubir, UBIR); - imx_uart_writel(sport, ubmr, UBMR); - imx_uart_writel(sport, uts, IMX21_UTS); } static void -- 2.25.1
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