1 files changed, 159 insertions, 0 deletions
diff --git a/drivers/acpi/csrt.c b/drivers/acpi/csrt.c
new file mode 100644
index 000000000000..5c15a91faf0b
--- /dev/null
+++ b/drivers/acpi/csrt.c
@@ -0,0 +1,159 @@
+/*
+ * Support for Core System Resources Table (CSRT)
+ *
+ * Copyright (C) 2013, Intel Corporation
+ * Authors: Mika Westerberg <[email protected]>
+ *	    Andy Shevchenko <[email protected]>
+ *
+ * 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);
+	}
+}