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 <andriy.shevchenko@linux.intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

1 files changed, 169 insertions, 3 deletions

diff --git a/drivers/dma/acpi-dma.c b/drivers/dma/acpi-dma.c
index ba6fc62e9651..5a18f82f732a 100644
--- a/drivers/dma/acpi-dma.c
+++ b/drivers/dma/acpi-dma.c
@@ -4,7 +4,8 @@
  * Based on of-dma.c
  *
  * Copyright (C) 2013, Intel Corporation
- * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ * Authors: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
+ *          Mika Westerberg <mika.westerberg@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
@@ -16,6 +17,7 @@
 #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>
 
@@ -23,6 +25,117 @@ 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
  * @dev:                struct device of DMA controller
  * @acpi_dma_xlate:     translation function which converts a dma specifier
@@ -61,6 +174,8 @@ int acpi_dma_controller_register(struct device *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);
         list_add_tail(&adma->dma_controllers, &acpi_dma_list);
@@ -149,6 +264,45 @@ void devm_acpi_dma_controller_free(struct device *dev)
 }
 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;
@@ -193,6 +347,7 @@ struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *dev,
         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))
@@ -219,9 +374,20 @@ struct dma_chan *acpi_dma_request_slave_chan_by_index(struct device *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;
         }