| /* |
| * 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> |
| |
| /* |
| * 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, 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; |
| } |
| |
| /* |
| * 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"); |
| 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 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 |
| */ |
| 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; |
| } |