1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (c) 2012, Intel Corporation 4 * Copyright (c) 2015, Red Hat, Inc. 5 * Copyright (c) 2015, 2016 Linaro Ltd. 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 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 20 * acpi_parse_spcr(). 21 */ 22 bool qdf2400_e44_present; 23 EXPORT_SYMBOL(qdf2400_e44_present); 24 25 /* 26 * Some Qualcomm Datacenter Technologies SoCs have a defective UART BUSY bit. 27 * Detect them by examining the OEM fields in the SPCR header, similar to PCI 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) && 39 h->oem_revision == 1) 40 return true; 41 42 return false; 43 } 44 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 { 52 bool xgene_8250 = false; 53 54 if (tb->interface_type != ACPI_DBG2_16550_COMPATIBLE) 55 return false; 56 57 if (memcmp(tb->header.oem_id, "APMC0D", ACPI_OEM_ID_SIZE) && 58 memcmp(tb->header.oem_id, "HPE ", ACPI_OEM_ID_SIZE)) 59 return false; 60 61 if (!memcmp(tb->header.oem_table_id, "XGENESPC", 62 ACPI_OEM_TABLE_ID_SIZE) && tb->header.oem_revision == 0) 63 xgene_8250 = true; 64 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; 70 } 71 72 /** 73 * acpi_parse_spcr() - parse ACPI SPCR table and add preferred console 74 * 75 * @enable_earlycon: set up earlycon for the console specified by the table 76 * @enable_console: setup the console specified by the table. 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 80 * console is registered and if @enable_earlycon is true, earlycon is set up. 81 * If @enable_console is true the system console is also configured. 82 * 83 * When CONFIG_ACPI_SPCR_TABLE is defined, this function should be called 84 * from arch initialization code as soon as the DT/ACPI decision is made. 85 * 86 */ 87 int __init acpi_parse_spcr(bool enable_earlycon, bool enable_console) 88 { 89 static char opts[64]; 90 struct acpi_table_spcr *table; 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; 99 100 status = acpi_get_table(ACPI_SIG_SPCR, 0, 101 (struct acpi_table_header **)&table); 102 103 if (ACPI_FAILURE(status)) 104 return -ENOENT; 105 106 if (table->header.revision < 2) 107 pr_info("SPCR table version %d\n", table->header.revision); 108 109 if (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { 110 switch (ACPI_ACCESS_BIT_WIDTH(( 111 table->serial_port.access_width))) { 112 default: 113 pr_err("Unexpected SPCR Access Width. Defaulting to byte size\n"); 114 /* fall through */ 115 case 8: 116 iotype = "mmio"; 117 break; 118 case 16: 119 iotype = "mmio16"; 120 break; 121 case 32: 122 iotype = "mmio32"; 123 break; 124 } 125 } else 126 iotype = "io"; 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) { 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; 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 } 170 171 /* 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; 191 if (enable_earlycon) 192 uart = "qdf2400_e44"; 193 } 194 195 if (xgene_8250_erratum_present(table)) { 196 iotype = "mmio32"; 197 198 /* 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 */ 202 baud_rate = 0; 203 } 204 205 if (!baud_rate) { 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 } 212 213 pr_info("console: %s\n", opts); 214 215 if (enable_earlycon) 216 setup_earlycon(opts); 217 218 if (enable_console) 219 err = add_preferred_console(uart, 0, opts + strlen(uart) + 1); 220 else 221 err = 0; 222 done: 223 acpi_put_table((struct acpi_table_header *)table); 224 return err; 225 } 226