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

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (c) 2012, Intel Corporation
 * Copyright (c) 2015, Red Hat, Inc.
 * Copyright (c) 2015, 2016 Linaro Ltd.
 */

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

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

/*
 * Erratum 44 for QDF2432v1 and QDF2400v1 SoCs describes the BUSY bit as
 * occasionally getting stuck as 1. To avoid the potential for a hang, check
 * TXFE == 0 instead of BUSY == 1. This may not be suitable for all UART
 * implementations, so only do so if an affected platform is detected in
 * acpi_parse_spcr().
 */
bool qdf2400_e44_present;
EXPORT_SYMBOL(qdf2400_e44_present);

/*
 * Some Qualcomm Datacenter Technologies SoCs have a defective UART BUSY bit.
 * Detect them by examining the OEM fields in the SPCR header, similar 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 == 1)
		return true;

	return false;
}

/*
 * APM X-Gene v1 and v2 UART hardware is an 16550 like device but has its
 * register aligned to 32-bit. In addition, the BIOS also encoded the
 * access width to be 8 bits. This function detects this errata condition.
 */
static bool xgene_8250_erratum_present(struct acpi_table_spcr *tb)
{
	bool xgene_8250 = false;

	if (tb->interface_type != ACPI_DBG2_16550_COMPATIBLE)
		return false;

	if (memcmp(tb->header.oem_id, "APMC0D", ACPI_OEM_ID_SIZE) &&
	    memcmp(tb->header.oem_id, "HPE   ", ACPI_OEM_ID_SIZE))
		return false;

	if (!memcmp(tb->header.oem_table_id, "XGENESPC",
	    ACPI_OEM_TABLE_ID_SIZE) && tb->header.oem_revision == 0)
		xgene_8250 = true;

	if (!memcmp(tb->header.oem_table_id, "ProLiant",
	    ACPI_OEM_TABLE_ID_SIZE) && tb->header.oem_revision == 1)
		xgene_8250 = true;

	return xgene_8250;
}

/**
 * acpi_parse_spcr() - parse ACPI SPCR table and add preferred console
 *
 * @enable_earlycon: set up earlycon for the console specified by the table
 * @enable_console: setup 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 @enable_earlycon is true, earlycon is set up.
 * If @enable_console is true the system console is also configured.
 *
 * When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called
 * from arch initialization code as soon as the DT/ACPI decision is made.
 *
 */
int __init acpi_parse_spcr(bool enable_earlycon, bool enable_console)
{
	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)
		pr_info("SPCR table version %d\n", table->header.revision);

	if (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
		switch (ACPI_ACCESS_BIT_WIDTH((
			table->serial_port.access_width))) {
		default:
			pr_err("Unexpected SPCR Access Width.  Defaulting to byte size\n");
			/* fall through */
		case 8:
			iotype = "mmio";
			break;
		case 16:
			iotype = "mmio16";
			break;
		case 32:
			iotype = "mmio32";
			break;
		}
	} else
		iotype = "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 0:
		/*
		 * SPCR 1.04 defines 0 as a preconfigured state of UART.
		 * Assume firmware or bootloader configures console correctly.
		 */
		baud_rate = 0;
		break;
	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 the E44 erratum is required, then we need to tell the pl011
	 * driver to implement the work-around.
	 *
	 * The global variable is used by the probe function when it
	 * creates the UARTs, whether or not they're used as a console.
	 *
	 * If the user specifies "traditional" earlycon, the qdf2400_e44
	 * console name matches the EARLYCON_DECLARE() statement, and
	 * SPCR is not used.  Parameter "earlycon" is false.
	 *
	 * If the user specifies "SPCR" earlycon, then we need to update
	 * the console name so that it also says "qdf2400_e44".  Parameter
	 * "earlycon" is true.
	 *
	 * For consistency, if we change the console name, then we do it
	 * for everyone, not just earlycon.
	 */
	if (qdf2400_erratum_44_present(&table->header)) {
		qdf2400_e44_present = true;
		if (enable_earlycon)
			uart = "qdf2400_e44";
	}

	if (xgene_8250_erratum_present(table)) {
		iotype = "mmio32";

		/* for xgene v1 and v2 we don't know the clock rate of the
		 * UART so don't attempt to change to the baud rate state
		 * in the table because driver cannot calculate the dividers
		 */
		baud_rate = 0;
	}

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

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

	if (enable_earlycon)
		setup_earlycon(opts);

	if (enable_console)
		err = add_preferred_console(uart, 0, opts + strlen(uart) + 1);
	else
		err = 0;
done:
	acpi_put_table((struct acpi_table_header *)table);
	return err;
}
Commit	Line	Data
d2912cb1	1	// SPDX-License-Identifier: GPL-2.0-only
ad1696f6 AM	2	/*
	3	* Copyright (c) 2012, Intel Corporation
	4	* Copyright (c) 2015, Red Hat, Inc.
	5	* Copyright (c) 2015, 2016 Linaro Ltd.
ad1696f6 AM	6	*/
	7
	8	#define pr_fmt(fmt) "ACPI: SPCR: " fmt
	9
	10	#include <linux/acpi.h>
	11	#include <linux/console.h>
	12	#include <linux/kernel.h>
	13	#include <linux/serial_core.h>
	14
37ef38f3 TT	15	/*
	16	* Erratum 44 for QDF2432v1 and QDF2400v1 SoCs describes the BUSY bit as
	17	* occasionally getting stuck as 1. To avoid the potential for a hang, check
	18	* TXFE == 0 instead of BUSY == 1. This may not be suitable for all UART
	19	* implementations, so only do so if an affected platform is detected in
0231d000	20	* acpi_parse_spcr().
37ef38f3 TT	21	*/
	22	bool qdf2400_e44_present;
	23	EXPORT_SYMBOL(qdf2400_e44_present);
	24
d8a4995b CC	25	/*
d8a4995b CC	26	* Some Qualcomm Datacenter Technologies SoCs have a defective UART BUSY bit.
603fadf3	27	* Detect them by examining the OEM fields in the SPCR header, similar to PCI
d8a4995b CC	28	* quirk detection in pci_mcfg.c.
	29	*/
	30	static bool qdf2400_erratum_44_present(struct acpi_table_header *h)
	31	{
	32	if (memcmp(h->oem_id, "QCOM ", ACPI_OEM_ID_SIZE))
	33	return false;
	34
	35	if (!memcmp(h->oem_table_id, "QDF2432 ", ACPI_OEM_TABLE_ID_SIZE))
	36	return true;
	37
	38	if (!memcmp(h->oem_table_id, "QDF2400 ", ACPI_OEM_TABLE_ID_SIZE) &&
542ed784	39	h->oem_revision == 1)
d8a4995b CC	40	return true;
	41
	42	return false;
	43	}
	44
79a64832 LH	45	/*
	46	* APM X-Gene v1 and v2 UART hardware is an 16550 like device but has its
	47	* register aligned to 32-bit. In addition, the BIOS also encoded the
	48	* access width to be 8 bits. This function detects this errata condition.
	49	*/
	50	static bool xgene_8250_erratum_present(struct acpi_table_spcr *tb)
	51	{
dee82bc1 GG	52	bool xgene_8250 = false;
dee82bc1 GG	53
79a64832 LH	54	if (tb->interface_type != ACPI_DBG2_16550_COMPATIBLE)
	55	return false;
	56
dee82bc1 GG	57	if (memcmp(tb->header.oem_id, "APMC0D", ACPI_OEM_ID_SIZE) &&
dee82bc1 GG	58	memcmp(tb->header.oem_id, "HPE ", ACPI_OEM_ID_SIZE))
79a64832 LH	59	return false;
	60
	61	if (!memcmp(tb->header.oem_table_id, "XGENESPC",
	62	ACPI_OEM_TABLE_ID_SIZE) && tb->header.oem_revision == 0)
dee82bc1	63	xgene_8250 = true;
79a64832	64
dee82bc1 GG	65	if (!memcmp(tb->header.oem_table_id, "ProLiant",
	66	ACPI_OEM_TABLE_ID_SIZE) && tb->header.oem_revision == 1)
	67	xgene_8250 = true;
	68
	69	return xgene_8250;
79a64832 LH	70	}
79a64832 LH	71
ad1696f6	72	/**
0231d000	73	* acpi_parse_spcr() - parse ACPI SPCR table and add preferred console
ad1696f6	74	*
0231d000 PB	75	* @enable_earlycon: set up earlycon for the console specified by the table
0231d000 PB	76	* @enable_console: setup the console specified by the table.
ad1696f6 AM	77	*
	78	* For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be
	79	* defined to parse ACPI SPCR table. As a result of the parsing preferred
0231d000 PB	80	* console is registered and if @enable_earlycon is true, earlycon is set up.
0231d000 PB	81	* If @enable_console is true the system console is also configured.
ad1696f6 AM	82	*
ad1696f6 AM	83	* When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called
183b8021	84	* from arch initialization code as soon as the DT/ACPI decision is made.
ad1696f6 AM	85	*
ad1696f6 AM	86	*/
0231d000	87	int __init acpi_parse_spcr(bool enable_earlycon, bool enable_console)
ad1696f6 AM	88	{
	89	static char opts[64];
	90	struct acpi_table_spcr *table;
ad1696f6 AM	91	acpi_status status;
	92	char *uart;
	93	char *iotype;
	94	int baud_rate;
	95	int err;
	96
	97	if (acpi_disabled)
	98	return -ENODEV;
	99
6b11d1d6 LZ	100	status = acpi_get_table(ACPI_SIG_SPCR, 0,
6b11d1d6 LZ	101	(struct acpi_table_header **)&table);
ad1696f6 AM	102
	103	if (ACPI_FAILURE(status))
	104	return -ENOENT;
	105
0231d000 PB	106	if (table->header.revision < 2)
0231d000 PB	107	pr_info("SPCR table version %d\n", table->header.revision);
ad1696f6	108
2bece493	109	if (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
4eebedd8 LZ	110	switch (ACPI_ACCESS_BIT_WIDTH((
4eebedd8 LZ	111	table->serial_port.access_width))) {
2bece493 LH	112	default:
2bece493 LH	113	pr_err("Unexpected SPCR Access Width. Defaulting to byte size\n");
5a9e59e8	114	/* fall through */
4eebedd8	115	case 8:
2bece493 LH	116	iotype = "mmio";
2bece493 LH	117	break;
4eebedd8	118	case 16:
2bece493 LH	119	iotype = "mmio16";
2bece493 LH	120	break;
4eebedd8	121	case 32:
2bece493 LH	122	iotype = "mmio32";
	123	break;
	124	}
	125	} else
	126	iotype = "io";
ad1696f6 AM	127
	128	switch (table->interface_type) {
	129	case ACPI_DBG2_ARM_SBSA_32BIT:
	130	iotype = "mmio32";
	131	/* fall through */
	132	case ACPI_DBG2_ARM_PL011:
	133	case ACPI_DBG2_ARM_SBSA_GENERIC:
	134	case ACPI_DBG2_BCM2835:
	135	uart = "pl011";
	136	break;
	137	case ACPI_DBG2_16550_COMPATIBLE:
	138	case ACPI_DBG2_16550_SUBSET:
	139	uart = "uart";
	140	break;
	141	default:
	142	err = -ENOENT;
	143	goto done;
	144	}
	145
	146	switch (table->baud_rate) {
b413b1ab AS	147	case 0:
	148	/*
	149	* SPCR 1.04 defines 0 as a preconfigured state of UART.
	150	* Assume firmware or bootloader configures console correctly.
	151	*/
	152	baud_rate = 0;
	153	break;
ad1696f6 AM	154	case 3:
	155	baud_rate = 9600;
	156	break;
	157	case 4:
	158	baud_rate = 19200;
	159	break;
	160	case 6:
	161	baud_rate = 57600;
	162	break;
	163	case 7:
	164	baud_rate = 115200;
	165	break;
	166	default:
	167	err = -ENOENT;
	168	goto done;
	169	}
	170
37ef38f3 TT	171	/*
	172	* If the E44 erratum is required, then we need to tell the pl011
	173	* driver to implement the work-around.
	174	*
	175	* The global variable is used by the probe function when it
	176	* creates the UARTs, whether or not they're used as a console.
	177	*
	178	* If the user specifies "traditional" earlycon, the qdf2400_e44
	179	* console name matches the EARLYCON_DECLARE() statement, and
	180	* SPCR is not used. Parameter "earlycon" is false.
	181	*
	182	* If the user specifies "SPCR" earlycon, then we need to update
	183	* the console name so that it also says "qdf2400_e44". Parameter
	184	* "earlycon" is true.
	185	*
	186	* For consistency, if we change the console name, then we do it
	187	* for everyone, not just earlycon.
	188	*/
	189	if (qdf2400_erratum_44_present(&table->header)) {
	190	qdf2400_e44_present = true;
0231d000	191	if (enable_earlycon)
37ef38f3 TT	192	uart = "qdf2400_e44";
	193	}
	194
03c3876f	195	if (xgene_8250_erratum_present(table)) {
79a64832	196	iotype = "mmio32";
d8a4995b	197
03c3876f GG	198	/* for xgene v1 and v2 we don't know the clock rate of the
	199	* UART so don't attempt to change to the baud rate state
	200	* in the table because driver cannot calculate the dividers
	201	*/
b413b1ab AS	202	baud_rate = 0;
	203	}
	204
	205	if (!baud_rate) {
03c3876f GG	206	snprintf(opts, sizeof(opts), "%s,%s,0x%llx", uart, iotype,
	207	table->serial_port.address);
	208	} else {
	209	snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
	210	table->serial_port.address, baud_rate);
	211	}
ad1696f6 AM	212
	213	pr_info("console: %s\n", opts);
	214
0231d000	215	if (enable_earlycon)
ad1696f6 AM	216	setup_earlycon(opts);
ad1696f6 AM	217
0231d000 PB	218	if (enable_console)
	219	err = add_preferred_console(uart, 0, opts + strlen(uart) + 1);
	220	else
	221	err = 0;
ad1696f6	222	done:
6b11d1d6	223	acpi_put_table((struct acpi_table_header *)table);
ad1696f6 AM	224	return err;
ad1696f6 AM	225	}