[mirror_ubuntu-zesty-kernel.git] / drivers / acpi / spcr.c

/*
 * Copyright (c) 2012, Intel Corporation
 * Copyright (c) 2015, Red Hat, Inc.
 * Copyright (c) 2015, 2016 Linaro Ltd.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#define pr_fmt(fmt) "ACPI: SPCR: " fmt

#include <linux/acpi.h>
#include <linux/console.h>
#include <linux/kernel.h>
#include <linux/serial_core.h>

/**
 * parse_spcr() - parse ACPI SPCR table and add preferred console
 *
 * @earlycon: set up earlycon for the console specified by the table
 *
 * For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be
 * defined to parse ACPI SPCR table.  As a result of the parsing preferred
 * console is registered and if @earlycon is true, earlycon is set up.
 *
 * When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called
 * from arch inintialization code as soon as the DT/ACPI decision is made.
 *
 */
int __init parse_spcr(bool earlycon)
{
	static char opts[64];
	struct acpi_table_spcr *table;
	acpi_status status;
	char *uart;
	char *iotype;
	int baud_rate;
	int err;

	if (acpi_disabled)
		return -ENODEV;

	status = acpi_get_table(ACPI_SIG_SPCR, 0,
				(struct acpi_table_header **)&table);

	if (ACPI_FAILURE(status))
		return -ENOENT;

	if (table->header.revision < 2) {
		err = -ENOENT;
		pr_err("wrong table version\n");
		goto done;
	}

	iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ?
			"mmio" : "io";

	switch (table->interface_type) {
	case ACPI_DBG2_ARM_SBSA_32BIT:
		iotype = "mmio32";
		/* fall through */
	case ACPI_DBG2_ARM_PL011:
	case ACPI_DBG2_ARM_SBSA_GENERIC:
	case ACPI_DBG2_BCM2835:
		uart = "pl011";
		break;
	case ACPI_DBG2_16550_COMPATIBLE:
	case ACPI_DBG2_16550_SUBSET:
		uart = "uart";
		break;
	default:
		err = -ENOENT;
		goto done;
	}

	switch (table->baud_rate) {
	case 3:
		baud_rate = 9600;
		break;
	case 4:
		baud_rate = 19200;
		break;
	case 6:
		baud_rate = 57600;
		break;
	case 7:
		baud_rate = 115200;
		break;
	default:
		err = -ENOENT;
		goto done;
	}

	snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
		 table->serial_port.address, baud_rate);

	pr_info("console: %s\n", opts);

	if (earlycon)
		setup_earlycon(opts);

	err = add_preferred_console(uart, 0, opts + strlen(uart) + 1);

done:
	acpi_put_table((struct acpi_table_header *)table);
	return err;
}
Commit	Line	Data
ad1696f6 AM	1	/*
	2	* Copyright (c) 2012, Intel Corporation
	3	* Copyright (c) 2015, Red Hat, Inc.
	4	* Copyright (c) 2015, 2016 Linaro Ltd.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 as
	8	* published by the Free Software Foundation.
	9	*
	10	*/
	11
	12	#define pr_fmt(fmt) "ACPI: SPCR: " fmt
	13
	14	#include <linux/acpi.h>
	15	#include <linux/console.h>
	16	#include <linux/kernel.h>
	17	#include <linux/serial_core.h>
	18
	19	/**
	20	* parse_spcr() - parse ACPI SPCR table and add preferred console
	21	*
	22	* @earlycon: set up earlycon for the console specified by the table
	23	*
	24	* For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be
	25	* defined to parse ACPI SPCR table. As a result of the parsing preferred
	26	* console is registered and if @earlycon is true, earlycon is set up.
	27	*
	28	* When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called
	29	* from arch inintialization code as soon as the DT/ACPI decision is made.
	30	*
	31	*/
	32	int __init parse_spcr(bool earlycon)
	33	{
	34	static char opts[64];
	35	struct acpi_table_spcr *table;
ad1696f6 AM	36	acpi_status status;
	37	char *uart;
	38	char *iotype;
	39	int baud_rate;
	40	int err;
	41
	42	if (acpi_disabled)
	43	return -ENODEV;
	44
6b11d1d6 LZ	45	status = acpi_get_table(ACPI_SIG_SPCR, 0,
6b11d1d6 LZ	46	(struct acpi_table_header **)&table);
ad1696f6 AM	47
	48	if (ACPI_FAILURE(status))
	49	return -ENOENT;
	50
	51	if (table->header.revision < 2) {
	52	err = -ENOENT;
	53	pr_err("wrong table version\n");
	54	goto done;
	55	}
	56
	57	iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ?
	58	"mmio" : "io";
	59
	60	switch (table->interface_type) {
	61	case ACPI_DBG2_ARM_SBSA_32BIT:
	62	iotype = "mmio32";
	63	/* fall through */
	64	case ACPI_DBG2_ARM_PL011:
	65	case ACPI_DBG2_ARM_SBSA_GENERIC:
	66	case ACPI_DBG2_BCM2835:
	67	uart = "pl011";
	68	break;
	69	case ACPI_DBG2_16550_COMPATIBLE:
	70	case ACPI_DBG2_16550_SUBSET:
	71	uart = "uart";
	72	break;
	73	default:
	74	err = -ENOENT;
	75	goto done;
	76	}
	77
	78	switch (table->baud_rate) {
	79	case 3:
	80	baud_rate = 9600;
	81	break;
	82	case 4:
	83	baud_rate = 19200;
	84	break;
	85	case 6:
	86	baud_rate = 57600;
	87	break;
	88	case 7:
	89	baud_rate = 115200;
	90	break;
	91	default:
	92	err = -ENOENT;
	93	goto done;
	94	}
	95
	96	snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
	97	table->serial_port.address, baud_rate);
	98
	99	pr_info("console: %s\n", opts);
	100
	101	if (earlycon)
	102	setup_earlycon(opts);
	103
	104	err = add_preferred_console(uart, 0, opts + strlen(uart) + 1);
	105
	106	done:
6b11d1d6	107	acpi_put_table((struct acpi_table_header *)table);
ad1696f6 AM	108	return err;
ad1696f6 AM	109	}