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serial: imx: factor-out common code to imx_uart_soft_reset()

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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 <sorganov@gmail.com>
Link: https://lore.kernel.org/r/20230201142700.4346-2-sorganov@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Sergey Organov 2023-02-01 17:26:54 +03:00 committed by Greg Kroah-Hartman
parent 8cf31a99d3
commit d45fb2e430
1 changed files with 37 additions and 36 deletions
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73
drivers/tty/serial/imx.c
View file

@ -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