Staging: vme: Attribute Testing For Dma Request

Check the directions in which the DMA controller is expected to operate
before giving control of a resource.
Signed-off-by: NMartyn Welch <martyn.welch@gefanuc.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/vme/TODO

@@ -4,28 +4,6 @@
 API
 ===
 
-DMA Resource Allocation incomplete
-----------------------------------
-
-The current DMA resource Allocation provides no means of selecting the
-suitability of a DMA controller based on it's supported modes of operation, as
-opposed to the resource allocation mechanisms for master and slave windows:
-
-	struct vme_resource *vme_dma_request(struct device *dev);
-
-As opposed to:
-
-	struct vme_resource * vme_master_request(struct device *dev,
-		vme_address_t aspace, vme_cycle_t cycle, vme_width_t width);
-
-The TSI148 can perform, VME-to-PCI, PCI-to-VME, PATTERN-to-VME, PATTERN-to-PCI,
-VME-to-VME and PCI-to-PCI transfers. The CA91C142 can only provide VME-to-PCI
-and PCI-to-VME.
-
-Add a mechanism to select a VME controller based on source/target type,
-required aspace, cycle and width requirements.
-
-
 Master window broadcast select mask
 -----------------------------------
 

drivers/staging/vme/bridges/vme_ca91cx42.c

@@ -1109,6 +1109,8 @@ static int ca91cx42_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		mutex_init(&(dma_ctrlr->mtx));
 		dma_ctrlr->locked = 0;
 		dma_ctrlr->number = i;
+		dma_ctrlr->route_attr = VME_DMA_VME_TO_MEM |
+			VME_DMA_MEM_TO_VME;
 		INIT_LIST_HEAD(&(dma_ctrlr->pending));
 		INIT_LIST_HEAD(&(dma_ctrlr->running));
 		list_add_tail(&(dma_ctrlr->list),

drivers/staging/vme/bridges/vme_tsi148.c

@@ -2421,6 +2421,10 @@ static int tsi148_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 		mutex_init(&(dma_ctrlr->mtx));
 		dma_ctrlr->locked = 0;
 		dma_ctrlr->number = i;
+		dma_ctrlr->route_attr = VME_DMA_VME_TO_MEM |
+			VME_DMA_MEM_TO_VME | VME_DMA_VME_TO_VME |
+			VME_DMA_MEM_TO_MEM | VME_DMA_PATTERN_TO_VME |
+			VME_DMA_PATTERN_TO_MEM;
 		INIT_LIST_HEAD(&(dma_ctrlr->pending));
 		INIT_LIST_HEAD(&(dma_ctrlr->running));
 		list_add_tail(&(dma_ctrlr->list),

drivers/staging/vme/vme.c

@@ -643,7 +643,7 @@ EXPORT_SYMBOL(vme_master_free);
  * Request a DMA controller with specific attributes, return some unique
  * identifier.
  */
-struct vme_resource *vme_dma_request(struct device *dev)
+struct vme_resource *vme_dma_request(struct device *dev, vme_dma_route_t route)
 {
 	struct vme_bridge *bridge;
 	struct list_head *dma_pos = NULL;
@@ -670,9 +670,11 @@ struct vme_resource *vme_dma_request(struct device *dev)
 			continue;
 		}
 
-		/* Find an unlocked controller */
+		/* Find an unlocked and compatible controller */
 		mutex_lock(&(dma_ctrlr->mtx));
-		if (dma_ctrlr->locked == 0) {
+		if (((dma_ctrlr->route_attr & route) == route) &&
+			(dma_ctrlr->locked == 0)) {
+
 			dma_ctrlr->locked = 1;
 			mutex_unlock(&(dma_ctrlr->mtx));
 			allocated_ctrlr = dma_ctrlr;

drivers/staging/vme/vme.h

@@ -68,6 +68,14 @@ typedef u32 vme_pattern_t;
 #define VME_DMA_PATTERN_WORD		(1<<1)
 #define VME_DMA_PATTERN_INCREMENT	(1<<2)
 
+typedef u32 vme_dma_route_t;
+#define VME_DMA_VME_TO_MEM		(1<<0)
+#define VME_DMA_MEM_TO_VME		(1<<1)
+#define VME_DMA_VME_TO_VME		(1<<2)
+#define VME_DMA_MEM_TO_MEM		(1<<3)
+#define VME_DMA_PATTERN_TO_VME		(1<<4)
+#define VME_DMA_PATTERN_TO_MEM		(1<<5)
+
 struct vme_dma_attr {
 	vme_dma_t type;
 	void *private;
@@ -124,7 +132,7 @@ unsigned int vme_master_rmw(struct vme_resource *, unsigned int, unsigned int,
 	unsigned int, loff_t);
 void vme_master_free(struct vme_resource *);
 
-struct vme_resource *vme_dma_request(struct device *);
+struct vme_resource *vme_dma_request(struct device *, vme_dma_route_t);
 struct vme_dma_list *vme_new_dma_list(struct vme_resource *);
 struct vme_dma_attr *vme_dma_pattern_attribute(u32, vme_pattern_t);
 struct vme_dma_attr *vme_dma_pci_attribute(dma_addr_t);

drivers/staging/vme/vme_api.txt

@@ -77,16 +77,21 @@ driver in question:
 	struct vme_resource * vme_slave_request(struct device *dev,
 		vme_address_t aspace, vme_cycle_t cycle);
 
-	struct vme_resource *vme_dma_request(struct device *dev);
+	struct vme_resource *vme_dma_request(struct device *dev,
+		vme_dma_route_t route);
 
 For slave windows these attributes are split into those of type 'vme_address_t'
-and 'vme_cycle_t'. Master windows add a further set of attributes 'vme_cycle_t'.
-These attributes are defined as bitmasks and as such any combination of the
-attributes can be requested for a single window, the core will assign a window
-that meets the requirements, returning a pointer of type vme_resource that
-should be used to identify the allocated resource when it is used. If an
-unallocated window fitting the requirements can not be found a NULL pointer will
-be returned.
+and 'vme_cycle_t'. Master windows add a further set of attributes
+'vme_cycle_t'.  These attributes are defined as bitmasks and as such any
+combination of the attributes can be requested for a single window, the core
+will assign a window that meets the requirements, returning a pointer of type
+vme_resource that should be used to identify the allocated resource when it is
+used. For DMA controllers, the request function requires the potential
+direction of any transfers to be provided in the route attributes. This is
+typically VME-to-MEM and/or MEM-to-VME, though some hardware can support
+VME-to-VME and MEM-to-MEM transfers as well as test pattern generation. If an
+unallocated window fitting the requirements can not be found a NULL pointer
+will be returned.
 
 Functions are also provided to free window allocations once they are no longer
 required. These functions should be passed the pointer to the resource provided
@@ -237,6 +242,12 @@ covered under "Transfer Attributes"):
 		struct vme_dma_attr *src, struct vme_dma_attr *dest,
 		size_t count);
 
+NOTE:	The detailed attributes of the transfers source and destination
+	are not checked until an entry is added to a DMA list, the request
+	for a DMA channel purely checks the directions in which the
+	controller is expected to transfer data. As a result it is
+	possible for this call to return an error, for example if the
+	source or destination is in an unsupported VME address space.
 
 Transfer Attributes
 -------------------

drivers/staging/vme/vme_bridge.h

@@ -64,6 +64,7 @@ struct vme_dma_resource {
 	int number;
 	struct list_head pending;
 	struct list_head running;
+	vme_dma_route_t route_attr;
 };
 
 struct vme_lm_resource {