- VME Device Driver API
- =====================
+ TODO
+ ====
-Driver registration
-===================
+API
+===
-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 follwoing function:
+DMA Resource Allocation incomplete
+----------------------------------
- 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;
- char *name;
- const struct vme_device_id *bind_table;
- int (*probe) (struct device *, int, int);
- int (*remove) (struct device *, int, int);
- void (*shutdown) (void);
- struct device_driver driver;
- };
-
-At the minimum, the ???.name???, ???.probe??? and ???.bind_table??? elements of this
-structure should be correctly set. The ???.name??? element is a pointer to a string
-holding the device driver???s name. The ???.probe??? element should contain a pointer
-to the probe routine.
-
-The arguments of the probe routine are as follows:
-
- probe(struct device *dev, int bus, int slot);
-
-The ???.bind_table??? is a pointer to an array of type ???vme_device_id???:
-
- struct vme_device_id {
- int bus;
- int slot;
- };
-
-Each structure in this array should provide a bus and slot number where the core
-should probe, using the driver???s probe routine, for a device on the specified
-VME bus.
-
-The VME subsystem supports a single VME driver per ???slot???. There are considered
-to be 32 slots per bus, one for each slot-ID as defined in the ANSI/VITA 1-1994
-specification and are analogious to the physical slots on the VME backplane.
-
-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 probe routine will
-be called for each of the bus/slot combination that becomes valid as VME buses
-are themselves registered. 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 device *dev,
- vme_address_t aspace, vme_cycle_t cycle, vme_width_t width);
-
- struct vme_resource * vme_slave_request(struct device *dev,
- vme_address_t aspace, vme_cycle_t cycle);
-
-TODO: DMA Resource Allocation incomplete. No attribute based selection.
+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_request_dma(struct device *dev);
-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.
-
-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 dependant on
-the underlying chipset. A window must be configured before it can be used.
-
+As opposed to:
-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,
+ struct vme_resource * vme_master_request(struct device *dev,
vme_address_t aspace, vme_cycle_t cycle, vme_width_t width);
- int vme_master_get (struct vme_resource *res, int *enabled,
- unsigned long long *base, unsigned long long *size,
- vme_address_t *aspace, vme_cycle_t *cycle, vme_width_t *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.
+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.
-These functions return 0 on success or an error code should the call fail.
+Add a mechanism to select a VME controller based on source/target type,
+required aspace, cycle and width requirements.
Master window broadcast select mask
-----------------------------------
-TODO: Add functions to set and get Broadcast Select mask:
+API currently provides no method to set or get Broadcast Select mask. Suggest
+somthing like:
int vme_master_bmsk_set (struct vme_resource *res, int mask);
int vme_master_bmsk_get (struct vme_resource *res, int *mask);
-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 dependant 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, vme_address_t aspace, vme_cycle_t cycle);
-
- int vme_slave_get (struct vme_resource *res, int *enabled,
- unsigned long long *base, unsigned long long *size,
- dma_addr_t *mem, vme_address_t *aspace, vme_cycle_t *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);
-
-
-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,
- vme_pattern_t 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,
- vme_address_t aspace, vme_cycle_t cycle, vme_width_t 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_request_irq(struct device *dev, int level, int statid,
- void (*callback)(int, int, void *), void *priv);
-
- void vme_free_irq(struct device *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_generate_irq(struct device *dev, int level, int statid);
-
-
-Location monitors
-=================
-
-The VME API provides the following functionality to configure the location
-monitor.
-
+Add optional timeout when waiting for an IACK.
-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:
+CR/CSR Buffer
+-------------
- struct vme_resource * vme_lm_request(struct device *dev);
+The VME API provides no functions to access the buffer mapped into the CR/CSR
+space.
- 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:
+Mailboxes
+---------
- int vme_lm_count(struct vme_resource * res);
+Whilst not part of the VME specification, they are provided by a number of
+chips. They are currently not supported at all by the API.
-Location Monitor Configuration
-------------------------------
+Core
+====
-Once a bank of location monitors has been allocated, the following functions
-are provided to configure the location and mode of the location monitor:
+- Rename vme_master_resource's "pci_resource" to be bus agnostic.
+- Improve generic sanity checks (Such as does an offset and size fit within a
+ window and parameter checking).
- int vme_lm_set(struct vme_resource *res, unsigned long long base,
- vme_address_t aspace, vme_cycle_t cycle);
-
- int vme_lm_get(struct vme_resource *res, unsigned long long *base,
- vme_address_t *aspace, vme_cycle_t *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);
-
-
-CR/CSR
-======
-
-TODO: The VME API needs functions to access the CR/CSR buffer.
-
-Slot Detection
+Bridge Support
==============
-This function returns the slot ID of the provided bridge.
+Tempe (tsi148)
+--------------
+
+- Driver can currently only support a single bridge.
+- 2eSST Broadcast mode.
+- Mailboxes unsupported.
+- Improve error detection.
+- Control of prefetch size, threshold.
+- Arbiter control
+- Requestor control
+
+Universe II (ca91c142)
+----------------------
+
+- Driver can currently only support a single bridge.
+- DMA unsupported.
+- RMW transactions unsupported.
+- Location Monitors unsupported.
+- Mailboxes unsupported.
+- Error Detection.
+- Control of prefetch size, threshold.
+- Arbiter control
+- Requestor control
+- Slot detection
+
+Universe I (ca91x042)
+---------------------
+
+Currently completely unsupported.
- int vme_slot_get(struct device *dev);
--- /dev/null
+ 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 follwoing 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;
+ char *name;
+ const struct vme_device_id *bind_table;
+ int (*probe) (struct device *, int, int);
+ int (*remove) (struct device *, int, int);
+ void (*shutdown) (void);
+ struct device_driver driver;
+ };
+
+At the minimum, the '.name', '.probe' and '.bind_table' elements of this
+structure should be correctly set. The '.name' element is a pointer to a string
+holding the device driver's name. The '.probe' element should contain a pointer
+to the probe routine.
+
+The arguments of the probe routine are as follows:
+
+ probe(struct device *dev, int bus, int slot);
+
+The '.bind_table' is a pointer to an array of type 'vme_device_id':
+
+ struct vme_device_id {
+ int bus;
+ int slot;
+ };
+
+Each structure in this array should provide a bus and slot number where the core
+should probe, using the driver's probe routine, for a device on the specified
+VME bus.
+
+The VME subsystem supports a single VME driver per 'slot'. There are considered
+to be 32 slots per bus, one for each slot-ID as defined in the ANSI/VITA 1-1994
+specification and are analogious to the physical slots on the VME backplane.
+
+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 probe routine will
+be called for each of the bus/slot combination that becomes valid as VME buses
+are themselves registered. 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 device *dev,
+ vme_address_t aspace, vme_cycle_t cycle, vme_width_t width);
+
+ struct vme_resource * vme_slave_request(struct device *dev,
+ vme_address_t aspace, vme_cycle_t cycle);
+
+ struct vme_resource *vme_request_dma(struct device *dev);
+
+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.
+
+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 dependant 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,
+ vme_address_t aspace, vme_cycle_t cycle, vme_width_t width);
+
+ int vme_master_get (struct vme_resource *res, int *enabled,
+ unsigned long long *base, unsigned long long *size,
+ vme_address_t *aspace, vme_cycle_t *cycle, vme_width_t *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 dependant 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, vme_address_t aspace, vme_cycle_t cycle);
+
+ int vme_slave_get (struct vme_resource *res, int *enabled,
+ unsigned long long *base, unsigned long long *size,
+ dma_addr_t *mem, vme_address_t *aspace, vme_cycle_t *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);
+
+
+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,
+ vme_pattern_t 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,
+ vme_address_t aspace, vme_cycle_t cycle, vme_width_t 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_request_irq(struct device *dev, int level, int statid,
+ void (*callback)(int, int, void *), void *priv);
+
+ void vme_free_irq(struct device *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_generate_irq(struct device *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 device *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,
+ vme_address_t aspace, vme_cycle_t cycle);
+
+ int vme_lm_get(struct vme_resource *res, unsigned long long *base,
+ vme_address_t *aspace, vme_cycle_t *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 device *dev);
projects / GitHub / LineageOS / android_kernel_samsung_universal7580.git / commitdiff