/* * 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 == 1) 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 initialization 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; }