Re: [PATCH 1/5] serial: lantiq: Add SMP support

From: Andy Shevchenko
Date: Wed Aug 07 2019 - 09:19:40 EST

On Wed, Aug 07, 2019 at 05:21:31PM +0800, Rahul Tanwar wrote:
> The existing driver can only support single core SoC. But new multicore
> platforms which reuse the same driver/IP need SMP support. This patch adds
> multicore support in the driver.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>

>
> Signed-off-by: Rahul Tanwar <rahul.tanwar@xxxxxxxxxxxxxxx>
> ---
> drivers/tty/serial/lantiq.c | 47 ++++++++++++++++++++++++++++++---------------
> 1 file changed, 32 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/tty/serial/lantiq.c b/drivers/tty/serial/lantiq.c
> index 9de9f0f239a1..42e27b48e9cc 100644
> --- a/drivers/tty/serial/lantiq.c
> +++ b/drivers/tty/serial/lantiq.c
> @@ -99,7 +99,6 @@
> static void lqasc_tx_chars(struct uart_port *port);
> static struct ltq_uart_port *lqasc_port[MAXPORTS];
> static struct uart_driver lqasc_reg;
> -static DEFINE_SPINLOCK(ltq_asc_lock);
>
> struct ltq_uart_port {
> struct uart_port port;
> @@ -110,6 +109,7 @@ struct ltq_uart_port {
> unsigned int tx_irq;
> unsigned int rx_irq;
> unsigned int err_irq;
> + spinlock_t lock; /* exclusive access for multi core */
> };
>
> static inline void asc_update_bits(u32 clear, u32 set, void __iomem *reg)
> @@ -135,9 +135,11 @@ static void
> lqasc_start_tx(struct uart_port *port)
> {
> unsigned long flags;
> - spin_lock_irqsave(&ltq_asc_lock, flags);
> + struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
> +
> + spin_lock_irqsave(&ltq_port->lock, flags);
> lqasc_tx_chars(port);
> - spin_unlock_irqrestore(&ltq_asc_lock, flags);
> + spin_unlock_irqrestore(&ltq_port->lock, flags);
> return;
> }
>
> @@ -245,9 +247,11 @@ lqasc_tx_int(int irq, void *_port)
> {
> unsigned long flags;
> struct uart_port *port = (struct uart_port *)_port;
> - spin_lock_irqsave(&ltq_asc_lock, flags);
> + struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
> +
> + spin_lock_irqsave(&ltq_port->lock, flags);
> __raw_writel(ASC_IRNCR_TIR, port->membase + LTQ_ASC_IRNCR);
> - spin_unlock_irqrestore(&ltq_asc_lock, flags);
> + spin_unlock_irqrestore(&ltq_port->lock, flags);
> lqasc_start_tx(port);
> return IRQ_HANDLED;
> }
> @@ -257,11 +261,13 @@ lqasc_err_int(int irq, void *_port)
> {
> unsigned long flags;
> struct uart_port *port = (struct uart_port *)_port;
> - spin_lock_irqsave(&ltq_asc_lock, flags);
> + struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
> +
> + spin_lock_irqsave(&ltq_port->lock, flags);
> /* clear any pending interrupts */
> asc_update_bits(0, ASCWHBSTATE_CLRPE | ASCWHBSTATE_CLRFE |
> ASCWHBSTATE_CLRROE, port->membase + LTQ_ASC_WHBSTATE);
> - spin_unlock_irqrestore(&ltq_asc_lock, flags);
> + spin_unlock_irqrestore(&ltq_port->lock, flags);
> return IRQ_HANDLED;
> }
>
> @@ -270,10 +276,12 @@ lqasc_rx_int(int irq, void *_port)
> {
> unsigned long flags;
> struct uart_port *port = (struct uart_port *)_port;
> - spin_lock_irqsave(&ltq_asc_lock, flags);
> + struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
> +
> + spin_lock_irqsave(&ltq_port->lock, flags);
> __raw_writel(ASC_IRNCR_RIR, port->membase + LTQ_ASC_IRNCR);
> lqasc_rx_chars(port);
> - spin_unlock_irqrestore(&ltq_asc_lock, flags);
> + spin_unlock_irqrestore(&ltq_port->lock, flags);
> return IRQ_HANDLED;
> }
>
> @@ -307,11 +315,13 @@ lqasc_startup(struct uart_port *port)
> {
> struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
> int retval;
> + unsigned long flags;
>
> if (!IS_ERR(ltq_port->clk))
> clk_prepare_enable(ltq_port->clk);
> port->uartclk = clk_get_rate(ltq_port->freqclk);
>
> + spin_lock_irqsave(&ltq_port->lock, flags);
> asc_update_bits(ASCCLC_DISS | ASCCLC_RMCMASK, (1 << ASCCLC_RMCOFFSET),
> port->membase + LTQ_ASC_CLC);
>
> @@ -331,6 +341,8 @@ lqasc_startup(struct uart_port *port)
> asc_update_bits(0, ASCCON_M_8ASYNC | ASCCON_FEN | ASCCON_TOEN |
> ASCCON_ROEN, port->membase + LTQ_ASC_CON);
>
> + spin_unlock_irqrestore(&ltq_port->lock, flags);
> +
> retval = request_irq(ltq_port->tx_irq, lqasc_tx_int,
> 0, "asc_tx", port);
> if (retval) {
> @@ -367,15 +379,19 @@ static void
> lqasc_shutdown(struct uart_port *port)
> {
> struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
> + unsigned long flags;
> +
> free_irq(ltq_port->tx_irq, port);
> free_irq(ltq_port->rx_irq, port);
> free_irq(ltq_port->err_irq, port);
>
> + spin_lock_irqsave(&ltq_port->lock, flags);
> __raw_writel(0, port->membase + LTQ_ASC_CON);
> asc_update_bits(ASCRXFCON_RXFEN, ASCRXFCON_RXFFLU,
> port->membase + LTQ_ASC_RXFCON);
> asc_update_bits(ASCTXFCON_TXFEN, ASCTXFCON_TXFFLU,
> port->membase + LTQ_ASC_TXFCON);
> + spin_unlock_irqrestore(&ltq_port->lock, flags);
> if (!IS_ERR(ltq_port->clk))
> clk_disable_unprepare(ltq_port->clk);
> }
> @@ -390,6 +406,7 @@ lqasc_set_termios(struct uart_port *port,
> unsigned int baud;
> unsigned int con = 0;
> unsigned long flags;
> + struct ltq_uart_port *ltq_port = to_ltq_uart_port(port);
>
> cflag = new->c_cflag;
> iflag = new->c_iflag;
> @@ -443,7 +460,7 @@ lqasc_set_termios(struct uart_port *port,
> /* set error signals - framing, parity and overrun, enable receiver */
> con |= ASCCON_FEN | ASCCON_TOEN | ASCCON_ROEN;
>
> - spin_lock_irqsave(&ltq_asc_lock, flags);
> + spin_lock_irqsave(&ltq_port->lock, flags);
>
> /* set up CON */
> asc_update_bits(0, con, port->membase + LTQ_ASC_CON);
> @@ -471,7 +488,7 @@ lqasc_set_termios(struct uart_port *port,
> /* enable rx */
> __raw_writel(ASCWHBSTATE_SETREN, port->membase + LTQ_ASC_WHBSTATE);
>
> - spin_unlock_irqrestore(&ltq_asc_lock, flags);
> + spin_unlock_irqrestore(&ltq_port->lock, flags);
>
> /* Don't rewrite B0 */
> if (tty_termios_baud_rate(new))
> @@ -589,17 +606,14 @@ lqasc_console_putchar(struct uart_port *port, int ch)
> static void lqasc_serial_port_write(struct uart_port *port, const char *s,
> u_int count)
> {
> - unsigned long flags;
> -
> - spin_lock_irqsave(&ltq_asc_lock, flags);
> uart_console_write(port, s, count, lqasc_console_putchar);
> - spin_unlock_irqrestore(&ltq_asc_lock, flags);
> }
>
> static void
> lqasc_console_write(struct console *co, const char *s, u_int count)
> {
> struct ltq_uart_port *ltq_port;
> + unsigned long flags;
>
> if (co->index >= MAXPORTS)
> return;
> @@ -608,7 +622,9 @@ lqasc_console_write(struct console *co, const char *s, u_int count)
> if (!ltq_port)
> return;
>
> + spin_lock_irqsave(&ltq_port->lock, flags);
> lqasc_serial_port_write(&ltq_port->port, s, count);
> + spin_unlock_irqrestore(&ltq_port->lock, flags);
> }
>
> static int __init
> @@ -766,6 +782,7 @@ lqasc_probe(struct platform_device *pdev)
> ltq_port->rx_irq = irqres[1].start;
> ltq_port->err_irq = irqres[2].start;
>
> + spin_lock_init(&ltq_port->lock);
> lqasc_port[line] = ltq_port;
> platform_set_drvdata(pdev, ltq_port);
>
> --
> 2.11.0
>

--
With Best Regards,
Andy Shevchenko