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Commit bd94c407 authored by Masahiro Yamada's avatar Masahiro Yamada Committed by Greg Kroah-Hartman
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serial: support 16-bit register interface for console 



Currently, 8-bit (MMIO) and 32-bit (MMIO32) register interfaces are
supported for the 8250 console, but the 16-bit (MMIO16) is not.
The 8250 UART device on my board is connected to a 16-bit bus and
my main motivation is to use earlycon with it.
(Refer to arch/arm/boot/dts/uniphier-support-card.dtsi)

Signed-off-by: default avatarMasahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: default avatarPeter Hurley <peter@hurleysoftware.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 004e2ed5

Documentation/kernel-parameters.txt

+5 −4
Original line number Diff line number Diff line
@@ -721,16 +721,17 @@ bytes respectively. Such letter suffixes can also be entirely omitted. 


		uart[8250],io,<addr>[,options]

		uart[8250],mmio,<addr>[,options]

		uart[8250],mmio16,<addr>[,options]

		uart[8250],mmio32,<addr>[,options]

		uart[8250],0x<addr>[,options]

			Start an early, polled-mode console on the 8250/16550

			UART at the specified I/O port or MMIO address,

			switching to the matching ttyS device later.

			MMIO inter-register address stride is either 8-bit

			(mmio) or 32-bit (mmio32).

			If none of [io|mmio|mmio32], <addr> is assumed to be

			equivalent to 'mmio'. 'options' are specified in the

			same format described for ttyS above; if unspecified,

			(mmio), 16-bit (mmio16), or 32-bit (mmio32).

			If none of [io|mmio|mmio16|mmio32], <addr> is assumed

			to be equivalent to 'mmio'. 'options' are specified in

			the same format described for ttyS above; if unspecified,

			the h/w is not re-initialized.



		hvc<n>	Use the hypervisor console device <n>. This is for

drivers/tty/serial/8250/8250_core.c

+4 −3
Original line number Diff line number Diff line
@@ -620,7 +620,7 @@ static int univ8250_console_setup(struct console *co, char *options) 
 *	@options: ptr to option string from console command line

 *

 *	Only attempts to match console command lines of the form:

 *	    console=uart[8250],io|mmio|mmio32,<addr>[,<options>]

 *	    console=uart[8250],io|mmio|mmio16|mmio32,<addr>[,<options>]

 *	    console=uart[8250],0x<addr>[,<options>]

 *	This form is used to register an initial earlycon boot console and

 *	replace it with the serial8250_console at 8250 driver init.
@@ -650,8 +650,9 @@ static int univ8250_console_match(struct console *co, char *name, int idx, 


		if (port->iotype != iotype)

			continue;

		if ((iotype == UPIO_MEM || iotype == UPIO_MEM32) &&

		    (port->mapbase != addr))

		if ((iotype == UPIO_MEM || iotype == UPIO_MEM16 ||

		     iotype == UPIO_MEM32 || iotype == UPIO_MEM32BE)

		    && (port->mapbase != addr))

			continue;

		if (iotype == UPIO_PORT && port->iobase != addr)

			continue;

drivers/tty/serial/8250/8250_early.c

+5 −0
Original line number Diff line number Diff line
@@ -42,6 +42,8 @@ static unsigned int __init serial8250_early_in(struct uart_port *port, int offse 
	switch (port->iotype) {

	case UPIO_MEM:

		return readb(port->membase + offset);

	case UPIO_MEM16:

		return readw(port->membase + (offset << 1));

	case UPIO_MEM32:

		return readl(port->membase + (offset << 2));

	case UPIO_MEM32BE:
@@ -59,6 +61,9 @@ static void __init serial8250_early_out(struct uart_port *port, int offset, int 
	case UPIO_MEM:

		writeb(value, port->membase + offset);

		break;

	case UPIO_MEM16:

		writew(value, port->membase + (offset << 1));

		break;

	case UPIO_MEM32:

		writel(value, port->membase + (offset << 2));

		break;

drivers/tty/serial/8250/8250_port.c

+20 −0
Original line number Diff line number Diff line
@@ -368,6 +368,18 @@ static void mem_serial_out(struct uart_port *p, int offset, int value) 
	writeb(value, p->membase + offset);

}



static void mem16_serial_out(struct uart_port *p, int offset, int value)

{

	offset = offset << p->regshift;

	writew(value, p->membase + offset);

}



static unsigned int mem16_serial_in(struct uart_port *p, int offset)

{

	offset = offset << p->regshift;

	return readw(p->membase + offset);

}



static void mem32_serial_out(struct uart_port *p, int offset, int value)

{

	offset = offset << p->regshift;
@@ -425,6 +437,11 @@ static void set_io_from_upio(struct uart_port *p) 
		p->serial_out = mem_serial_out;

		break;



	case UPIO_MEM16:

		p->serial_in = mem16_serial_in;

		p->serial_out = mem16_serial_out;

		break;



	case UPIO_MEM32:

		p->serial_in = mem32_serial_in;

		p->serial_out = mem32_serial_out;
@@ -459,6 +476,7 @@ serial_port_out_sync(struct uart_port *p, int offset, int value) 
{

	switch (p->iotype) {

	case UPIO_MEM:

	case UPIO_MEM16:

	case UPIO_MEM32:

	case UPIO_MEM32BE:

	case UPIO_AU:
@@ -2462,6 +2480,7 @@ static int serial8250_request_std_resource(struct uart_8250_port *up) 
	case UPIO_TSI:

	case UPIO_MEM32:

	case UPIO_MEM32BE:

	case UPIO_MEM16:

	case UPIO_MEM:

		if (!port->mapbase)

			break;
@@ -2499,6 +2518,7 @@ static void serial8250_release_std_resource(struct uart_8250_port *up) 
	case UPIO_TSI:

	case UPIO_MEM32:

	case UPIO_MEM32BE:

	case UPIO_MEM16:

	case UPIO_MEM:

		if (!port->mapbase)

			break;

drivers/tty/serial/earlycon.c

+11 −4
Original line number Diff line number Diff line
@@ -71,10 +71,16 @@ static int __init parse_options(struct earlycon_device *device, char *options) 
		return -EINVAL;



	switch (port->iotype) {

	case UPIO_MEM:

		port->mapbase = addr;

		break;

	case UPIO_MEM16:

		port->regshift = 1;

		port->mapbase = addr;

		break;

	case UPIO_MEM32:

	case UPIO_MEM32BE:

		port->regshift = 2;	/* fall-through */

	case UPIO_MEM:

		port->regshift = 2;

		port->mapbase = addr;

		break;

	case UPIO_PORT:
@@ -91,10 +97,11 @@ static int __init parse_options(struct earlycon_device *device, char *options) 
		strlcpy(device->options, options, length);

	}



	if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM32 ||

	    port->iotype == UPIO_MEM32BE)

	if (port->iotype == UPIO_MEM || port->iotype == UPIO_MEM16 ||

	    port->iotype == UPIO_MEM32 || port->iotype == UPIO_MEM32BE)

		pr_info("Early serial console at MMIO%s 0x%llx (options '%s')\n",

			(port->iotype == UPIO_MEM) ? "" :

			(port->iotype == UPIO_MEM16) ? "16" :

			(port->iotype == UPIO_MEM32) ? "32" : "32be",

			(unsigned long long)port->mapbase,

			device->options);