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Commit 2e0842a1 authored by Geert Uytterhoeven's avatar Geert Uytterhoeven Committed by Greg Kroah-Hartman
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serial: sh-sci: Use the correct register for overrun checks 



The various SCI implementations use 3 different methods to signal
overrun errors:
  - Bit SCI_ORER in register SCxSR on SCI,
  - Bit SCIFA_ORER in register SCxSR on SCIFA and SCIFB, and SCIF on
    SH7705/SH7720/SH7721,
  - Bit SCLSR_ORER in (optional!) register SCLSR on (H)SCIF.

However:
  1. sci_handle_fifo_overrun()
       a. handles (H)SCIF and SCIFA/SCIFB only,
       b. treats SCIF on SH7705/SH7720/SH7721 incorrectly,
  2. sci_mpxed_interrupt()
       a. treats SCIF on SH7705/SH7720/SH7721 incorrectly,
       b. ignores that not all SCIFs have the SCLSR register, causing
	  "Invalid register access" WARN()ings.

To fix the above:
  1. Determine and store the correct register enum during
     initialization,
  2. Replace the duplicated buggy switch statements by using the stored
     register enum,
  3. Add the missing existence check to  sci_mpxed_interrupt().

Signed-off-by: default avatarGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 75c249fd

drivers/tty/serial/sh-sci.c

+15 −25
Original line number Diff line number Diff line
@@ -81,6 +81,7 @@ struct sci_port { 


	/* Platform configuration */

	struct plat_sci_port	*cfg;

	unsigned int		overrun_reg;

	unsigned int		overrun_mask;

	unsigned int		error_mask;

	unsigned int		sampling_rate;
@@ -866,30 +867,17 @@ static int sci_handle_fifo_overrun(struct uart_port *port) 
	struct tty_port *tport = &port->state->port;

	struct sci_port *s = to_sci_port(port);

	struct plat_sci_reg *reg;

	int copied = 0, offset;

	int copied = 0;

	u16 status;



	switch (port->type) {

	case PORT_SCIF:

	case PORT_HSCIF:

		offset = SCLSR;

		break;

	case PORT_SCIFA:

	case PORT_SCIFB:

		offset = SCxSR;

		break;

	default:

		return 0;

	}



	reg = sci_getreg(port, offset);

	reg = sci_getreg(port, s->overrun_reg);

	if (!reg->size)

		return 0;



	status = serial_port_in(port, offset);

	status = serial_port_in(port, s->overrun_reg);

	if (status & s->overrun_mask) {

		status &= ~s->overrun_mask;

		serial_port_out(port, offset, status);

		serial_port_out(port, s->overrun_reg, status);



		port->icount.overrun++;
@@ -1041,15 +1029,11 @@ static irqreturn_t sci_mpxed_interrupt(int irq, void *ptr) 


	ssr_status = serial_port_in(port, SCxSR);

	scr_status = serial_port_in(port, SCSCR);

	switch (port->type) {

	case PORT_SCIF:

	case PORT_HSCIF:

		orer_status = serial_port_in(port, SCLSR);

		break;

	case PORT_SCIFA:

	case PORT_SCIFB:

	if (s->overrun_reg == SCxSR)

		orer_status = ssr_status;

		break;

	else {

		if (sci_getreg(port, s->overrun_reg)->size)

			orer_status = serial_port_in(port, s->overrun_reg);

	}



	err_enabled = scr_status & port_rx_irq_mask(port);
@@ -2254,31 +2238,37 @@ static int sci_init_single(struct platform_device *dev, 
	switch (p->type) {

	case PORT_SCIFB:

		port->fifosize = 256;

		sci_port->overrun_reg = SCxSR;

		sci_port->overrun_mask = SCIFA_ORER;

		sampling_rate = 16;

		break;

	case PORT_HSCIF:

		port->fifosize = 128;

		sampling_rate = 0;

		sci_port->overrun_reg = SCLSR;

		sci_port->overrun_mask = SCLSR_ORER;

		break;

	case PORT_SCIFA:

		port->fifosize = 64;

		sci_port->overrun_reg = SCxSR;

		sci_port->overrun_mask = SCIFA_ORER;

		sampling_rate = 16;

		break;

	case PORT_SCIF:

		port->fifosize = 16;

		if (p->regtype == SCIx_SH7705_SCIF_REGTYPE) {

			sci_port->overrun_reg = SCxSR;

			sci_port->overrun_mask = SCIFA_ORER;

			sampling_rate = 16;

		} else {

			sci_port->overrun_reg = SCLSR;

			sci_port->overrun_mask = SCLSR_ORER;

			sampling_rate = 32;

		}

		break;

	default:

		port->fifosize = 1;

		sci_port->overrun_reg = SCxSR;

		sci_port->overrun_mask = SCI_ORER;

		sampling_rate = 32;

		break;