From d45fb2e430e54fac6af3cabb39c36171c4bf3f52 Mon Sep 17 00:00:00 2001 From: Sergey Organov Date: Wed, 1 Feb 2023 17:26:54 +0300 Subject: [PATCH] serial: imx: factor-out common code to imx_uart_soft_reset() 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 Link: https://lore.kernel.org/r/20230201142700.4346-2-sorganov@gmail.com Signed-off-by: Greg Kroah-Hartman --- 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 0e0590d1b123..e7c88e7528d7 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -397,6 +397,39 @@ static void start_hrtimer_ms(struct hrtimer *hrt, unsigned long msec) hrtimer_start(hrt, ms_to_ktime(msec), HRTIMER_MODE_REL); } +/* 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) { @@ -1400,7 +1433,7 @@ static void imx_uart_disable_dma(struct imx_port *sport) static int imx_uart_startup(struct uart_port *port) { struct imx_port *sport = (struct imx_port *)port; - int retval, i; + int retval; unsigned long flags; int dma_is_inited = 0; u32 ucr1, ucr2, ucr3, ucr4, uts; @@ -1432,15 +1465,9 @@ 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); + imx_uart_soft_reset(sport); /* * Finally, clear and enable interrupts @@ -1596,8 +1623,6 @@ 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; @@ -1615,32 +1640,8 @@ 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); + imx_uart_soft_reset(sport); - 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); - - /* Restore the registers */ - imx_uart_writel(sport, ubir, UBIR); - imx_uart_writel(sport, ubmr, UBMR); - imx_uart_writel(sport, uts, IMX21_UTS); } static void