> I believe that my proposal would make it much easier for
> reduce the dependency on struct pci_device, because it should
> greatly reduce the amount of code that would have to be changed.
>Fine but do it when we have the abstration to actually
>make it work, not before. [...]
How can I help? Who is working on this? Is this just an idea
right now? Are there patches floating around?
If you want this to work through drivers/base, I could rename
struct bus_type to struct device_type (it really quite misnamed), and
create a new struct bus. Here is roughly what I have in mind. I am
cc'ing linux-kenrel in case anyone else wants to point out problems
or indicate that they are working on this.
struct bus_type {
#ifdef CONFIG_DEVICEFS /* I really want to be able to config driverfs out */
const char *name; /* "pci", "isa", "sbus"... */
#endif
(void *)(*alloc_consistent)(struct device *dev, size_t size,
dma_addr_t *dma_addr);
void (*free_conistent)(struct device *dev, size_t size,
void *addr, dma_addr_t dma_handle);
map_single...
unmap_single...
sync_single...
};
struct device {
...
struct bus_type *bus_type;
struct device_type *dev_type; /* Formerly device.bus */
u64 dma_mask; /* less than device.parent.dma_mask
Individual DMA channels on this
device might have tighter masks
than this, but will never have
looser ones. */
}
static inline void*
dma_alloc_consistent(struct device *dev, size_t size, dma_addr_t *dma_addr)
{
return (*dev->bus_type->alloc_consistent)(dev, size, dma_addr);
}
static inline dma_addr_t
dma_map_single(struct device *dev, void *vaddr, size_t size, int direction)
{
#ifdef NEED_SEPARATE_DMA_ADDR
return (*dev->bus_type->map_single)(dev, vaddr, size, directio);
#else
return virt_to_bus(vaddr);
#endif
}
static inline void pci_unmap_single(struct device *dev, dma_addr_t dma_addr,
size_t size, int direction)
{
if (direction == PCI_DMA_NONE)
BUG();
#ifdef NEED_SEPARATE_DMA_ADDR
(*dev->bus_type->unmap_single)(dev, dma_addr, size, direction);
#endif
}
...in include/pci.h:...
/* Implemented in each arch subdirectory */
static void *__pci_alloc_consistent(struct device *dev, size_t size,
dma_addr_t *dma_addr);
/* Legacy interface */
static inline void *pci_alloc_consistent(struct device *pcidev, size_t size,
dma_addr_t *dma_addr)
{
return __pci_alloc_consistent(&pcidev->dev, size, dma_addr);
}
....Somewhere in drivers/pci:....
struct bus_type pci_bus_type = {
.name = "pci",
.alloc_consistent = __pci_alloc_consistent,
...
};
...Somewhere in drivers/?....
/* ISA uses the PCI routines. */
struct bus_type isa_bus_type = {
.name = "isa",
.alloc_consistent = __pci_alloc_consistent,
...
};
...Somewhere in drivers/sbus... */
struct bus_type isa_bus_type = {
.name = "isa",
.alloc_consistent = __sbus_alloc_consistent,
...
};
...In each arch/xxxx/pci.c...
void *__pci_alloc_consistent(struct device *dev, size_t size,
dma_addr_t *dma_addr)
{
struct pci_dev *pci_dev = list_entry(dev, struct pci_dev, dev);
...guts of existing pci_alloc_consistent implementation...
}
Adam J. Richter __ ______________ 575 Oroville Road
adam@yggdrasil.com \ / Milpitas, California 95035
+1 408 309-6081 | g g d r a s i l United States of America
"Free Software For The Rest Of Us."
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This archive was generated by hypermail 2b29 : Sun Jun 30 2002 - 22:00:10 EST