linux-imx

/*

 * 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;