/*
* Support for Core System Resources Table (CSRT)
*
* Copyright (C) 2013, Intel Corporation
* Authors: Mika Westerberg <mika.westerberg@linux.intel.com>
* Andy Shevchenko <andriy.shevchenko@linux.intel.com>
*
* 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: CSRT: " fmt
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/sizes.h>
ACPI_MODULE_NAME("CSRT");
static int __init acpi_csrt_parse_shared_info(struct platform_device *pdev,
const struct acpi_csrt_group *grp)
{
const struct acpi_csrt_shared_info *si;
struct resource res[3];
size_t nres;
int ret;
memset(res, 0, sizeof(res));
nres = 0;
si = (const struct acpi_csrt_shared_info *)&grp[1];
/*
* The peripherals that are listed on CSRT typically support only
* 32-bit addresses so we only use the low part of MMIO base for
* now.
*/
if (!si->mmio_base_high && si->mmio_base_low) {
/*
* There is no size of the memory resource in shared_info
* so we assume that it is 4k here.
*/
res[nres].start = si->mmio_base_low;
res[nres].end = res[0].start + SZ_4K - 1;
res[nres++].flags = IORESOURCE_MEM;
}
if (si->gsi_interrupt) {
int irq = acpi_register_gsi(NULL, si->gsi_interrupt,
si->interrupt_mode,
si->interrupt_polarity);
res[nres].start = irq;
res[nres].end = irq;
res[nres++].flags = IORESOURCE_IRQ;
}
if (si->base_request_line || si->num_handshake_signals) {
/*
* We pass the driver a DMA resource describing the range
* of request lines the device supports.
*/
res[nres].start = si->base_request_line;
res[nres].end = res[nres].start + si->num_handshake_signals - 1;
res[nres++].flags = IORESOURCE_DMA;
}
ret = platform_device_add_resources(pdev, res, nres);
if (ret) {
if (si->gsi_interrupt)
acpi_unregister_gsi(si->gsi_interrupt);
return ret;
}
return 0;
}
static int __init
acpi_csrt_parse_resource_group(const struct acpi_csrt_group *grp)
{
struct platform_device *pdev;
char vendor[5], name[16];
int ret, i;
vendor[0] = grp->vendor_id;
vendor[1] = grp->vendor_id >> 8;
vendor[2] = grp->vendor_id >> 16;
vendor[3] = grp->vendor_id >> 24;
vendor[4] = '\0';
if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info))
return -ENODEV;
snprintf(name, sizeof(name), "%s%04X", vendor, grp->device_id);
pdev = platform_device_alloc(name, PLATFORM_DEVID_AUTO);
if (!pdev)
return -ENOMEM;
/* Add resources based on the shared info */
ret = acpi_csrt_parse_shared_info(pdev, grp);
if (ret)
goto fail;
ret = platform_device_add(pdev);
if (ret)
goto fail;
for (i = 0; i < pdev->num_resources; i++)
dev_dbg(&pdev->dev, "%pR\n", &pdev->resource[i]);
return 0;
fail:
platform_device_put(pdev);
return ret;
}
/*
* CSRT or Core System Resources Table is a proprietary ACPI table
* introduced by Microsoft. This table can contain devices that are not in
* the system DSDT table. In particular DMA controllers might be described
* here.
*
* We present these devices as normal platform devices that don't have ACPI
* IDs or handle. The platform device name will be something like
* <VENDOR><DEVID>.<n>.auto for example: INTL9C06.0.auto.
*/
void __init acpi_csrt_init(void)
{
struct acpi_csrt_group *grp, *end;
struct acpi_table_csrt *csrt;
acpi_status status;
int ret;
status = acpi_get_table(ACPI_SIG_CSRT, 0,
(struct acpi_table_header **)&csrt);
if (ACPI_FAILURE(status)) {
if (status != AE_NOT_FOUND)
pr_warn("failed to get the CSRT table\n");
return;
}
pr_debug("parsing CSRT table for devices\n");
grp = (struct acpi_csrt_group *)(csrt + 1);
end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length);
while (grp < end) {
ret = acpi_csrt_parse_resource_group(grp);
if (ret) {
pr_warn("error in parsing resource group: %d\n", ret);
return;
}
grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
}
}
