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authorMartyn Welch <martyn.welch@ge.com>2012-05-03 17:36:54 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-05-08 16:01:34 -0700
commitcc4729826fd1a478f235fbcf58c0f97663f8d7e3 (patch)
tree6941470e83d0dd00882e7ce020027b5494ad3ab0 /drivers/vme
parenta11cfdf4589f2f9f70d398d123c459d33dfc6bb2 (diff)
downloadlinux-cc4729826fd1a478f235fbcf58c0f97663f8d7e3.tar.gz
VME: Move API documentation to Documentation folder
The documentation for the VME device driver API is currently in drivers/vme/vme_api.txt, move this to Documentation/vme_api.txt Signed-of-by: Martyn Welch <martyn.welch@ge.com> Acked-by: Rob Landley <rob@landley.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/vme')
-rw-r--r--drivers/vme/vme_api.txt396
1 files changed, 0 insertions, 396 deletions
diff --git a/drivers/vme/vme_api.txt b/drivers/vme/vme_api.txt
deleted file mode 100644
index 856efa35f6e..00000000000
--- a/drivers/vme/vme_api.txt
+++ /dev/null
@@ -1,396 +0,0 @@
- VME Device Driver API
- =====================
-
-Driver registration
-===================
-
-As with other subsystems within the Linux kernel, VME device drivers register
-with the VME subsystem, typically called from the devices init routine. This is
-achieved via a call to the following function:
-
- int vme_register_driver (struct vme_driver *driver);
-
-If driver registration is successful this function returns zero, if an error
-occurred a negative error code will be returned.
-
-A pointer to a structure of type 'vme_driver' must be provided to the
-registration function. The structure is as follows:
-
- struct vme_driver {
- struct list_head node;
- const char *name;
- int (*match)(struct vme_dev *);
- int (*probe)(struct vme_dev *);
- int (*remove)(struct vme_dev *);
- void (*shutdown)(void);
- struct device_driver driver;
- struct list_head devices;
- unsigned int ndev;
- };
-
-At the minimum, the '.name', '.match' and '.probe' elements of this structure
-should be correctly set. The '.name' element is a pointer to a string holding
-the device driver's name.
-
-The '.match' function allows controlling the number of devices that need to
-be registered. The match function should return 1 if a device should be
-probed and 0 otherwise. This example match function (from vme_user.c) limits
-the number of devices probed to one:
-
- #define USER_BUS_MAX 1
- ...
- static int vme_user_match(struct vme_dev *vdev)
- {
- if (vdev->id.num >= USER_BUS_MAX)
- return 0;
- return 1;
- }
-
-The '.probe' element should contain a pointer to the probe routine. The
-probe routine is passed a 'struct vme_dev' pointer as an argument. The
-'struct vme_dev' structure looks like the following:
-
- struct vme_dev {
- int num;
- struct vme_bridge *bridge;
- struct device dev;
- struct list_head drv_list;
- struct list_head bridge_list;
- };
-
-Here, the 'num' field refers to the sequential device ID for this specific
-driver. The bridge number (or bus number) can be accessed using
-dev->bridge->num.
-
-A function is also provided to unregister the driver from the VME core and is
-usually called from the device driver's exit routine:
-
- void vme_unregister_driver (struct vme_driver *driver);
-
-
-Resource management
-===================
-
-Once a driver has registered with the VME core the provided match routine will
-be called the number of times specified during the registration. If a match
-succeeds, a non-zero value should be returned. A zero return value indicates
-failure. For all successful matches, the probe routine of the corresponding
-driver is called. The probe routine is passed a pointer to the devices
-device structure. This pointer should be saved, it will be required for
-requesting VME resources.
-
-The driver can request ownership of one or more master windows, slave windows
-and/or dma channels. Rather than allowing the device driver to request a
-specific window or DMA channel (which may be used by a different driver) this
-driver allows a resource to be assigned based on the required attributes of the
-driver in question:
-
- struct vme_resource * vme_master_request(struct vme_dev *dev,
- u32 aspace, u32 cycle, u32 width);
-
- struct vme_resource * vme_slave_request(struct vme_dev *dev, u32 aspace,
- u32 cycle);
-
- struct vme_resource *vme_dma_request(struct vme_dev *dev, u32 route);
-
-For slave windows these attributes are split into the VME address spaces that
-need to be accessed in 'aspace' and VME bus cycle types required in 'cycle'.
-Master windows add a further set of attributes in 'width' specifying the
-required data transfer widths. 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
-during resource allocation:
-
- void vme_master_free(struct vme_resource *res);
-
- void vme_slave_free(struct vme_resource *res);
-
- void vme_dma_free(struct vme_resource *res);
-
-
-Master windows
-==============
-
-Master windows provide access from the local processor[s] out onto the VME bus.
-The number of windows available and the available access modes is dependent on
-the underlying chipset. A window must be configured before it can be used.
-
-
-Master window configuration
----------------------------
-
-Once a master window has been assigned the following functions can be used to
-configure it and retrieve the current settings:
-
- int vme_master_set (struct vme_resource *res, int enabled,
- unsigned long long base, unsigned long long size, u32 aspace,
- u32 cycle, u32 width);
-
- int vme_master_get (struct vme_resource *res, int *enabled,
- unsigned long long *base, unsigned long long *size, u32 *aspace,
- u32 *cycle, u32 *width);
-
-The address spaces, transfer widths and cycle types are the same as described
-under resource management, however some of the options are mutually exclusive.
-For example, only one address space may be specified.
-
-These functions return 0 on success or an error code should the call fail.
-
-
-Master window access
---------------------
-
-The following functions can be used to read from and write to configured master
-windows. These functions return the number of bytes copied:
-
- ssize_t vme_master_read(struct vme_resource *res, void *buf,
- size_t count, loff_t offset);
-
- ssize_t vme_master_write(struct vme_resource *res, void *buf,
- size_t count, loff_t offset);
-
-In addition to simple reads and writes, a function is provided to do a
-read-modify-write transaction. This function returns the original value of the
-VME bus location :
-
- unsigned int vme_master_rmw (struct vme_resource *res,
- unsigned int mask, unsigned int compare, unsigned int swap,
- loff_t offset);
-
-This functions by reading the offset, applying the mask. If the bits selected in
-the mask match with the values of the corresponding bits in the compare field,
-the value of swap is written the specified offset.
-
-
-Slave windows
-=============
-
-Slave windows provide devices on the VME bus access into mapped portions of the
-local memory. The number of windows available and the access modes that can be
-used is dependent on the underlying chipset. A window must be configured before
-it can be used.
-
-
-Slave window configuration
---------------------------
-
-Once a slave window has been assigned the following functions can be used to
-configure it and retrieve the current settings:
-
- int vme_slave_set (struct vme_resource *res, int enabled,
- unsigned long long base, unsigned long long size,
- dma_addr_t mem, u32 aspace, u32 cycle);
-
- int vme_slave_get (struct vme_resource *res, int *enabled,
- unsigned long long *base, unsigned long long *size,
- dma_addr_t *mem, u32 *aspace, u32 *cycle);
-
-The address spaces, transfer widths and cycle types are the same as described
-under resource management, however some of the options are mutually exclusive.
-For example, only one address space may be specified.
-
-These functions return 0 on success or an error code should the call fail.
-
-
-Slave window buffer allocation
-------------------------------
-
-Functions are provided to allow the user to allocate and free a contiguous
-buffers which will be accessible by the VME bridge. These functions do not have
-to be used, other methods can be used to allocate a buffer, though care must be
-taken to ensure that they are contiguous and accessible by the VME bridge:
-
- void * vme_alloc_consistent(struct vme_resource *res, size_t size,
- dma_addr_t *mem);
-
- void vme_free_consistent(struct vme_resource *res, size_t size,
- void *virt, dma_addr_t mem);
-
-
-Slave window access
--------------------
-
-Slave windows map local memory onto the VME bus, the standard methods for
-accessing memory should be used.
-
-
-DMA channels
-============
-
-The VME DMA transfer provides the ability to run link-list DMA transfers. The
-API introduces the concept of DMA lists. Each DMA list is a link-list which can
-be passed to a DMA controller. Multiple lists can be created, extended,
-executed, reused and destroyed.
-
-
-List Management
----------------
-
-The following functions are provided to create and destroy DMA lists. Execution
-of a list will not automatically destroy the list, thus enabling a list to be
-reused for repetitive tasks:
-
- struct vme_dma_list *vme_new_dma_list(struct vme_resource *res);
-
- int vme_dma_list_free(struct vme_dma_list *list);
-
-
-List Population
----------------
-
-An item can be added to a list using the following function ( the source and
-destination attributes need to be created before calling this function, this is
-covered under "Transfer Attributes"):
-
- int vme_dma_list_add(struct vme_dma_list *list,
- 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
--------------------
-
-The attributes for the source and destination are handled separately from adding
-an item to a list. This is due to the diverse attributes required for each type
-of source and destination. There are functions to create attributes for PCI, VME
-and pattern sources and destinations (where appropriate):
-
-Pattern source:
-
- struct vme_dma_attr *vme_dma_pattern_attribute(u32 pattern, u32 type);
-
-PCI source or destination:
-
- struct vme_dma_attr *vme_dma_pci_attribute(dma_addr_t mem);
-
-VME source or destination:
-
- struct vme_dma_attr *vme_dma_vme_attribute(unsigned long long base,
- u32 aspace, u32 cycle, u32 width);
-
-The following function should be used to free an attribute:
-
- void vme_dma_free_attribute(struct vme_dma_attr *attr);
-
-
-List Execution
---------------
-
-The following function queues a list for execution. The function will return
-once the list has been executed:
-
- int vme_dma_list_exec(struct vme_dma_list *list);
-
-
-Interrupts
-==========
-
-The VME API provides functions to attach and detach callbacks to specific VME
-level and status ID combinations and for the generation of VME interrupts with
-specific VME level and status IDs.
-
-
-Attaching Interrupt Handlers
-----------------------------
-
-The following functions can be used to attach and free a specific VME level and
-status ID combination. Any given combination can only be assigned a single
-callback function. A void pointer parameter is provided, the value of which is
-passed to the callback function, the use of this pointer is user undefined:
-
- int vme_irq_request(struct vme_dev *dev, int level, int statid,
- void (*callback)(int, int, void *), void *priv);
-
- void vme_irq_free(struct vme_dev *dev, int level, int statid);
-
-The callback parameters are as follows. Care must be taken in writing a callback
-function, callback functions run in interrupt context:
-
- void callback(int level, int statid, void *priv);
-
-
-Interrupt Generation
---------------------
-
-The following function can be used to generate a VME interrupt at a given VME
-level and VME status ID:
-
- int vme_irq_generate(struct vme_dev *dev, int level, int statid);
-
-
-Location monitors
-=================
-
-The VME API provides the following functionality to configure the location
-monitor.
-
-
-Location Monitor Management
----------------------------
-
-The following functions are provided to request the use of a block of location
-monitors and to free them after they are no longer required:
-
- struct vme_resource * vme_lm_request(struct vme_dev *dev);
-
- void vme_lm_free(struct vme_resource * res);
-
-Each block may provide a number of location monitors, monitoring adjacent
-locations. The following function can be used to determine how many locations
-are provided:
-
- int vme_lm_count(struct vme_resource * res);
-
-
-Location Monitor Configuration
-------------------------------
-
-Once a bank of location monitors has been allocated, the following functions
-are provided to configure the location and mode of the location monitor:
-
- int vme_lm_set(struct vme_resource *res, unsigned long long base,
- u32 aspace, u32 cycle);
-
- int vme_lm_get(struct vme_resource *res, unsigned long long *base,
- u32 *aspace, u32 *cycle);
-
-
-Location Monitor Use
---------------------
-
-The following functions allow a callback to be attached and detached from each
-location monitor location. Each location monitor can monitor a number of
-adjacent locations:
-
- int vme_lm_attach(struct vme_resource *res, int num,
- void (*callback)(int));
-
- int vme_lm_detach(struct vme_resource *res, int num);
-
-The callback function is declared as follows.
-
- void callback(int num);
-
-
-Slot Detection
-==============
-
-This function returns the slot ID of the provided bridge.
-
- int vme_slot_get(struct vme_dev *dev);