v4.19.13 snapshot.
diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c
new file mode 100644
index 0000000..9d52743
--- /dev/null
+++ b/drivers/acpi/spcr.c
@@ -0,0 +1,218 @@
+/*
+ * 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");
+ /* 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 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;
+}