dma: acpi-dma: parse CSRT to extract additional resources

Since we have CSRT only to get additional DMA controller resources, let's get
rid of drivers/acpi/csrt.c and move its logic inside ACPI DMA helpers code.

Signed-off-by: Andy Shevchenko <[e-mail]>
Signed-off-by: Mika Westerberg <[e-mail]>
Acked-by: Rafael J. Wysocki <[e-mail]>
Signed-off-by: Vinod Koul <[e-mail]>

drivers/acpi/Makefile

···
 acpi-y				+= ec.o
 acpi-$(CONFIG_ACPI_DOCK)	+= dock.o
 acpi-y				+= pci_root.o pci_link.o pci_irq.o
-acpi-y				+= csrt.o
 acpi-$(CONFIG_X86_INTEL_LPSS)	+= acpi_lpss.o
 acpi-y				+= acpi_platform.o
 acpi-y				+= power.o

drivers/acpi/csrt.c

···
-/*
- * Support for Core System Resources Table (CSRT)
- *
- * Copyright (C) 2013, Intel Corporation
- * Authors: Mika Westerberg <[e-mail]>
- *	    Andy Shevchenko <[e-mail]>
- *
- * 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);
-	}
-}

drivers/acpi/internal.h

···
 void acpi_pci_root_hp_init(void);
 void acpi_platform_init(void);
 int acpi_sysfs_init(void);
-void acpi_csrt_init(void);
 #ifdef CONFIG_ACPI_CONTAINER
 void acpi_container_init(void);
 #else

drivers/acpi/scan.c

···
 	acpi_pci_link_init();
 	acpi_platform_init();
 	acpi_lpss_init();
-	acpi_csrt_init();
 	acpi_container_init();
 	acpi_memory_hotplug_init();
 

drivers/dma/acpi-dma.c

···
  * Based on of-dma.c
  *
  * Copyright (C) 2013, Intel Corporation
- * Author: Andy Shevchenko <[e-mail]>
+ * Authors: Andy Shevchenko <[e-mail]>
+ *	    Mika Westerberg <[e-mail]>
  *
  * 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
···
 #include <linux/list.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/ioport.h>
 #include <linux/acpi.h>
 #include <linux/acpi_dma.h>
 
 static LIST_HEAD(acpi_dma_list);
 static DEFINE_MUTEX(acpi_dma_lock);
+
+/**
+ * acpi_dma_parse_resource_group - match device and parse resource group
+ * @grp:	CSRT resource group
+ * @adev:	ACPI device to match with
+ * @adma:	struct acpi_dma of the given DMA controller
+ *
+ * Returns 1 on success, 0 when no information is available, or appropriate
+ * errno value on error.
+ *
+ * In order to match a device from DSDT table to the corresponding CSRT device
+ * we use MMIO address and IRQ.
+ */
+static int acpi_dma_parse_resource_group(const struct acpi_csrt_group *grp,
+		struct acpi_device *adev, struct acpi_dma *adma)
+{
+	const struct acpi_csrt_shared_info *si;
+	struct list_head resource_list;
+	struct resource_list_entry *rentry;
+	resource_size_t mem = 0, irq = 0;
+	u32 vendor_id;
+	int ret;
+
+	if (grp->shared_info_length != sizeof(struct acpi_csrt_shared_info))
+		return -ENODEV;
+
+	INIT_LIST_HEAD(&resource_list);
+	ret = acpi_dev_get_resources(adev, &resource_list, NULL, NULL);
+	if (ret <= 0)
+		return 0;
+
+	list_for_each_entry(rentry, &resource_list, node) {
+		if (resource_type(&rentry->res) == IORESOURCE_MEM)
+			mem = rentry->res.start;
+		else if (resource_type(&rentry->res) == IORESOURCE_IRQ)
+			irq = rentry->res.start;
+	}
+
+	acpi_dev_free_resource_list(&resource_list);
+
+	/* Consider initial zero values as resource not found */
+	if (mem == 0 && irq == 0)
+		return 0;
+
+	si = (const struct acpi_csrt_shared_info *)&grp[1];
+
+	/* Match device by MMIO and IRQ */
+	if (si->mmio_base_low != mem || si->gsi_interrupt != irq)
+		return 0;
+
+	vendor_id = le32_to_cpu(grp->vendor_id);
+	dev_dbg(&adev->dev, "matches with %.4s%04X (rev %u)\n",
+		(char *)&vendor_id, grp->device_id, grp->revision);
+
+	/* Check if the request line range is available */
+	if (si->base_request_line == 0 && si->num_handshake_signals == 0)
+		return 0;
+
+	adma->base_request_line = si->base_request_line;
+	adma->end_request_line = si->base_request_line +
+				 si->num_handshake_signals - 1;
+
+	dev_dbg(&adev->dev, "request line base: 0x%04x end: 0x%04x\n",
+		adma->base_request_line, adma->end_request_line);
+
+	return 1;
+}
+
+/**
+ * acpi_dma_parse_csrt - parse CSRT to exctract additional DMA resources
+ * @adev:	ACPI device to match with
+ * @adma:	struct acpi_dma of the given DMA controller
+ *
+ * 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 are using this table to get the request line range of the specific DMA
+ * controller to be used later.
+ *
+ */
+static void acpi_dma_parse_csrt(struct acpi_device *adev, struct acpi_dma *adma)
+{
+	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)
+			dev_warn(&adev->dev, "failed to get the CSRT table\n");
+		return;
+	}
+
+	grp = (struct acpi_csrt_group *)(csrt + 1);
+	end = (struct acpi_csrt_group *)((void *)csrt + csrt->header.length);
+
+	while (grp < end) {
+		ret = acpi_dma_parse_resource_group(grp, adev, adma);
+		if (ret < 0) {
+			dev_warn(&adev->dev,
+				 "error in parsing resource group\n");
+			return;
+		}
+
+		grp = (struct acpi_csrt_group *)((void *)grp + grp->length);
+	}
+}
 
 /**
  * acpi_dma_controller_register - Register a DMA controller to ACPI DMA helpers
···
 	adma->dev = dev;
 	adma->acpi_dma_xlate = acpi_dma_xlate;
 	adma->data = data;
+
+	acpi_dma_parse_csrt(adev, adma);
 
 	/* Now queue acpi_dma controller structure in list */
 	mutex_lock(&acpi_dma_lock);
···
 }
 EXPORT_SYMBOL_GPL(devm_acpi_dma_controller_free);
 
+/**
+ * acpi_dma_update_dma_spec - prepare dma specifier to pass to translation function
+ * @adma:	struct acpi_dma of DMA controller
+ * @dma_spec:	dma specifier to update
+ *
+ * Returns 0, if no information is avaiable, -1 on mismatch, and 1 otherwise.
+ *
+ * Accordingly to ACPI 5.0 Specification Table 6-170 "Fixed DMA Resource
+ * Descriptor":
+ *	DMA Request Line bits is a platform-relative number uniquely
+ *	identifying the request line assigned. Request line-to-Controller
+ *	mapping is done in a controller-specific OS driver.
+ * That's why we can safely adjust slave_id when the appropriate controller is
+ * found.
+ */
+static int acpi_dma_update_dma_spec(struct acpi_dma *adma,
+		struct acpi_dma_spec *dma_spec)
+{
+	/* Set link to the DMA controller device */
+	dma_spec->dev = adma->dev;
+
+	/* Check if the request line range is available */
+	if (adma->base_request_line == 0 && adma->end_request_line == 0)
+		return 0;
+
+	/* Check if slave_id falls to the range */
+	if (dma_spec->slave_id < adma->base_request_line ||
+	    dma_spec->slave_id > adma->end_request_line)
+		return -1;
+
+	/*
+	 * Here we adjust slave_id. It should be a relative number to the base
+	 * request line.
+	 */
+	dma_spec->slave_id -= adma->base_request_line;
+
+	return 1;
+}
+
 struct acpi_dma_parser_data {
 	struct acpi_dma_spec dma_spec;
 	size_t index;
···
 	struct acpi_device *adev;
 	struct acpi_dma *adma;
 	struct dma_chan *chan = NULL;
+	int found;
 
 	/* Check if the device was enumerated by ACPI */
 	if (!dev || !ACPI_HANDLE(dev))
···
 	mutex_lock(&acpi_dma_lock);
 
 	list_for_each_entry(adma, &acpi_dma_list, dma_controllers) {
-		dma_spec->dev = adma->dev;
+		/*
+		 * We are not going to call translation function if slave_id
+		 * doesn't fall to the request range.
+		 */
+		found = acpi_dma_update_dma_spec(adma, dma_spec);
+		if (found < 0)
+			continue;
 		chan = adma->acpi_dma_xlate(dma_spec, adma);
-		if (chan)
+		/*
+		 * Try to get a channel only from the DMA controller that
+		 * matches the slave_id. See acpi_dma_update_dma_spec()
+		 * description for the details.
+		 */
+		if (found > 0 || chan)
 			break;
 	}
 

include/linux/acpi_dma.h

···
  * @dev:		struct device of this controller
  * @acpi_dma_xlate:	callback function to find a suitable channel
  * @data:		private data used by a callback function
+ * @base_request_line:	first supported request line (CSRT)
+ * @end_request_line:	last supported request line (CSRT)
  */
 struct acpi_dma {
 	struct list_head	dma_controllers;
···
 	struct dma_chan		*(*acpi_dma_xlate)
 				(struct acpi_dma_spec *, struct acpi_dma *);
 	void			*data;
+	unsigned short		base_request_line;
+	unsigned short		end_request_line;
 };
 
 /* Used with acpi_dma_simple_xlate() */