2 * Copyright (c) 2012, Intel Corporation
3 * Copyright (c) 2015, Red Hat, Inc.
4 * Copyright (c) 2015, 2016 Linaro Ltd.
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.
12 #define pr_fmt(fmt) "ACPI: SPCR: " fmt
14 #include <linux/acpi.h>
15 #include <linux/console.h>
16 #include <linux/kernel.h>
17 #include <linux/serial_core.h>
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.
24 static bool qdf2400_erratum_44_present(struct acpi_table_header *h)
26 if (memcmp(h->oem_id, "QCOM ", ACPI_OEM_ID_SIZE))
29 if (!memcmp(h->oem_table_id, "QDF2432 ", ACPI_OEM_TABLE_ID_SIZE))
32 if (!memcmp(h->oem_table_id, "QDF2400 ", ACPI_OEM_TABLE_ID_SIZE) &&
40 * APM X-Gene v1 and v2 UART hardware is an 16550 like device but has its
41 * register aligned to 32-bit. In addition, the BIOS also encoded the
42 * access width to be 8 bits. This function detects this errata condition.
44 static bool xgene_8250_erratum_present(struct acpi_table_spcr *tb)
46 if (tb->interface_type != ACPI_DBG2_16550_COMPATIBLE)
49 if (memcmp(tb->header.oem_id, "APMC0D", ACPI_OEM_ID_SIZE))
52 if (!memcmp(tb->header.oem_table_id, "XGENESPC",
53 ACPI_OEM_TABLE_ID_SIZE) && tb->header.oem_revision == 0)
60 * parse_spcr() - parse ACPI SPCR table and add preferred console
62 * @earlycon: set up earlycon for the console specified by the table
64 * For the architectures with support for ACPI, CONFIG_ACPI_SPCR_TABLE may be
65 * defined to parse ACPI SPCR table. As a result of the parsing preferred
66 * console is registered and if @earlycon is true, earlycon is set up.
68 * When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called
69 * from arch initialization code as soon as the DT/ACPI decision is made.
72 int __init parse_spcr(bool earlycon)
75 struct acpi_table_spcr *table;
85 status = acpi_get_table(ACPI_SIG_SPCR, 0,
86 (struct acpi_table_header **)&table);
88 if (ACPI_FAILURE(status))
91 if (table->header.revision < 2) {
93 pr_err("wrong table version\n");
97 if (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) {
98 switch (table->serial_port.access_width) {
100 pr_err("Unexpected SPCR Access Width. Defaulting to byte size\n");
101 case ACPI_ACCESS_SIZE_BYTE:
104 case ACPI_ACCESS_SIZE_WORD:
107 case ACPI_ACCESS_SIZE_DWORD:
114 switch (table->interface_type) {
115 case ACPI_DBG2_ARM_SBSA_32BIT:
118 case ACPI_DBG2_ARM_PL011:
119 case ACPI_DBG2_ARM_SBSA_GENERIC:
120 case ACPI_DBG2_BCM2835:
123 case ACPI_DBG2_16550_COMPATIBLE:
124 case ACPI_DBG2_16550_SUBSET:
132 switch (table->baud_rate) {
150 if (qdf2400_erratum_44_present(&table->header))
151 uart = "qdf2400_e44";
152 if (xgene_8250_erratum_present(table))
155 snprintf(opts, sizeof(opts), "%s,%s,0x%llx,%d", uart, iotype,
156 table->serial_port.address, baud_rate);
158 pr_info("console: %s\n", opts);
161 setup_earlycon(opts);
163 err = add_preferred_console(uart, 0, opts + strlen(uart) + 1);
166 acpi_put_table((struct acpi_table_header *)table);