[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>

/*
 * Some Qualcomm Datacenter Technologies SoCs have a defective UART BUSY bit.
 * Detect them by examining the OEM fields in the SPCR header, similiar to PCI
 * quirk detection in pci_mcfg.c.
 */
static bool qdf2400_erratum_44_present(struct acpi_table_header *h)
{
	if (memcmp(h->oem_id, "QCOM  ", ACPI_OEM_ID_SIZE))
		return false;

	if (!memcmp(h->oem_table_id, "QDF2432 ", ACPI_OEM_TABLE_ID_SIZE))
		return true;

	if (!memcmp(h->oem_table_id, "QDF2400 ", ACPI_OEM_TABLE_ID_SIZE) &&
			h->oem_revision == 0)
		return true;

	return false;
}

/**
 * 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;
	}

	if (qdf2400_erratum_44_present(&table->header))
		uart = "qdf2400_e44";

	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
02f469fe SH	19	/*
	20	* Some Qualcomm Datacenter Technologies SoCs have a defective UART BUSY bit.
	21	* Detect them by examining the OEM fields in the SPCR header, similiar to PCI
	22	* quirk detection in pci_mcfg.c.
	23	*/
	24	static bool qdf2400_erratum_44_present(struct acpi_table_header *h)
	25	{
	26	if (memcmp(h->oem_id, "QCOM ", ACPI_OEM_ID_SIZE))
	27	return false;
	28
	29	if (!memcmp(h->oem_table_id, "QDF2432 ", ACPI_OEM_TABLE_ID_SIZE))
	30	return true;
	31
	32	if (!memcmp(h->oem_table_id, "QDF2400 ", ACPI_OEM_TABLE_ID_SIZE) &&
	33	h->oem_revision == 0)
	34	return true;
	35
	36	return false;
	37	}
	38
ad1696f6 AM	39	/**
	40	* parse_spcr() - parse ACPI SPCR table and add preferred console
	41	*
	42	* @earlycon: set up earlycon for the console specified by the table
	43	*
	44	* For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be
	45	* defined to parse ACPI SPCR table. As a result of the parsing preferred
	46	* console is registered and if @earlycon is true, earlycon is set up.
	47	*
	48	* When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called
	49	* from arch inintialization code as soon as the DT/ACPI decision is made.
	50	*
	51	*/
	52	int __init parse_spcr(bool earlycon)
	53	{
	54	static char opts[64];
	55	struct acpi_table_spcr *table;
ad1696f6 AM	56	acpi_status status;
	57	char *uart;
	58	char *iotype;
	59	int baud_rate;
	60	int err;
	61
	62	if (acpi_disabled)
	63	return -ENODEV;
	64
6b11d1d6 LZ	65	status = acpi_get_table(ACPI_SIG_SPCR, 0,
6b11d1d6 LZ	66	(struct acpi_table_header **)&table);
ad1696f6 AM	67
	68	if (ACPI_FAILURE(status))
	69	return -ENOENT;
	70
	71	if (table->header.revision < 2) {
	72	err = -ENOENT;
	73	pr_err("wrong table version\n");
	74	goto done;
	75	}
	76
	77	iotype = table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY ?
	78	"mmio" : "io";
	79
	80	switch (table->interface_type) {
	81	case ACPI_DBG2_ARM_SBSA_32BIT:
	82	iotype = "mmio32";
	83	/* fall through */
	84	case ACPI_DBG2_ARM_PL011:
	85	case ACPI_DBG2_ARM_SBSA_GENERIC:
	86	case ACPI_DBG2_BCM2835:
	87	uart = "pl011";
	88	break;
	89	case ACPI_DBG2_16550_COMPATIBLE:
	90	case ACPI_DBG2_16550_SUBSET:
	91	uart = "uart";
	92	break;
	93	default:
	94	err = -ENOENT;
	95	goto done;
	96	}
	97
	98	switch (table->baud_rate) {
	99	case 3:
	100	baud_rate = 9600;
	101	break;
	102	case 4:
	103	baud_rate = 19200;
	104	break;
	105	case 6:
	106	baud_rate = 57600;
	107	break;
	108	case 7:
	109	baud_rate = 115200;
	110	break;
	111	default:
	112	err = -ENOENT;
	113	goto done;
	114	}
	115
02f469fe SH	116	if (qdf2400_erratum_44_present(&table->header))
	117	uart = "qdf2400_e44";
	118
ad1696f6 AM	119	snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
	120	table->serial_port.address, baud_rate);
	121
	122	pr_info("console: %s\n", opts);
	123
	124	if (earlycon)
	125	setup_earlycon(opts);
	126
	127	err = add_preferred_console(uart, 0, opts + strlen(uart) + 1);
	128
	129	done:
6b11d1d6	130	acpi_put_table((struct acpi_table_header *)table);
ad1696f6 AM	131	return err;
ad1696f6 AM	132	}