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SubjectRe: [PATCH v4 3/6] PCI: endpoint: Add support to handle multiple base for mapping outbound memory
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Hi Prabhakar,

On 09/02/20 12:06 am, Lad Prabhakar wrote:
> R-Car PCIe controller has support to map multiple memory regions for
> mapping the outbound memory in local system also the controller limits
> single allocation for each region (that is, once a chunk is used from the
> region it cannot be used to allocate a new one). This features inspires to
> add support for handling multiple memory bases in endpoint framework.
>
> With this patch pci_epc_mem_init() now accepts multiple regions, also
> page_size for each memory region is passed during initialization so as
> to handle single allocation for each region by setting the page_size to
> window_size.

This patch looks much better now except for one comment below..
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> ---
> drivers/pci/controller/cadence/pcie-cadence-ep.c | 7 +-
> drivers/pci/controller/dwc/pcie-designware-ep.c | 29 ++--
> drivers/pci/controller/pcie-rockchip-ep.c | 7 +-
> drivers/pci/endpoint/pci-epc-mem.c | 166 ++++++++++++++++-------
> include/linux/pci-epc.h | 39 ++++--
> 5 files changed, 168 insertions(+), 80 deletions(-)
>
.
.
<snip>
.
.
> diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
> index d2b174c..b3eedee 100644
> --- a/drivers/pci/endpoint/pci-epc-mem.c
> +++ b/drivers/pci/endpoint/pci-epc-mem.c
> @@ -38,57 +38,76 @@ static int pci_epc_mem_get_order(struct pci_epc_mem *mem, size_t size)
> /**
> * __pci_epc_mem_init() - initialize the pci_epc_mem structure
> * @epc: the EPC device that invoked pci_epc_mem_init
> - * @phys_base: the physical address of the base
> - * @size: the size of the address space
> - * @page_size: size of each page
> + * @windows: pointer to windows supported by the device
> + * @num_windows: number of windows device supports
> *
> * Invoke to initialize the pci_epc_mem structure used by the
> * endpoint functions to allocate mapped PCI address.
> */
> -int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_base, size_t size,
> - size_t page_size)
> +int __pci_epc_mem_init(struct pci_epc *epc, struct pci_epc_mem_window *windows,
> + int num_windows)
> {
> - int ret;
> - struct pci_epc_mem *mem;
> - unsigned long *bitmap;
> + struct pci_epc_mem *mem = NULL;
> + unsigned long *bitmap = NULL;
> unsigned int page_shift;
> - int pages;
> + size_t page_size;
> int bitmap_size;
> -
> - if (page_size < PAGE_SIZE)
> - page_size = PAGE_SIZE;
> -
> - page_shift = ilog2(page_size);
> - pages = size >> page_shift;
> - bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
> -
> - mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> - if (!mem) {
> - ret = -ENOMEM;
> - goto err;
> - }
> -
> - bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> - if (!bitmap) {
> - ret = -ENOMEM;
> - goto err_mem;
> + int pages;
> + int ret;
> + int i;
> +
> + epc->mem_windows = 0;
> +
> + if (!windows)
> + return -EINVAL;
> +
> + if (num_windows <= 0)
> + return -EINVAL;
> +
> + epc->mem = kcalloc(num_windows, sizeof(*mem), GFP_KERNEL);
> + if (!epc->mem)
> + return -EINVAL;
> +
> + for (i = 0; i < num_windows; i++) {
> + page_size = windows[i].page_size;
> + if (page_size < PAGE_SIZE)
> + page_size = PAGE_SIZE;
> + page_shift = ilog2(page_size);
> + pages = windows[i].size >> page_shift;
> + bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
> +
> + mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> + if (!mem) {
> + ret = -ENOMEM;
> + goto err_mem;
> + }
> +
> + bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> + if (!bitmap) {
> + ret = -ENOMEM;
> + goto err_mem;
> + }
> +
> + mem->bitmap = bitmap;
> + mem->window.phys_base = windows[i].phys_base;
> + mem->page_size = page_size;
> + mem->pages = pages;
> + mem->window.size = windows[i].size;
> + epc->mem[i] = mem;
> }
> -
> - mem->bitmap = bitmap;
> - mem->phys_base = phys_base;
> - mem->page_size = page_size;
> - mem->pages = pages;
> - mem->size = size;
> -
> - epc->mem = mem;
> + epc->mem_windows = num_windows;
>
> return 0;
>
> err_mem:
> - kfree(mem);
> + for (; i >= 0; i--) {
> + mem = epc->mem[i];
> + kfree(mem->bitmap);
> + kfree(mem);
> + }
> + kfree(epc->mem);
>
> -err:
> -return ret;
> + return ret;
> }
> EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
>
> @@ -101,11 +120,21 @@ EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
> */
> void pci_epc_mem_exit(struct pci_epc *epc)
> {
> - struct pci_epc_mem *mem = epc->mem;
> + struct pci_epc_mem *mem;
> + int i;
> +
> + if (!epc->mem_windows)
> + return;
> +
> + for (i = 0; i <= epc->mem_windows; i++) {
> + mem = epc->mem[i];
> + kfree(mem->bitmap);
> + kfree(mem);
> + }
> + kfree(epc->mem);
>
> epc->mem = NULL;
> - kfree(mem->bitmap);
> - kfree(mem);
> + epc->mem_windows = 0;
> }
> EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
>
> @@ -121,20 +150,30 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
> void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
> phys_addr_t *phys_addr, size_t size)
> {
> - int pageno;
> - void __iomem *virt_addr;
> - struct pci_epc_mem *mem = epc->mem;
> - unsigned int page_shift = ilog2(mem->page_size);
> + void __iomem *virt_addr = NULL;
> + struct pci_epc_mem *mem;
> + unsigned int page_shift;
> + int pageno = -EINVAL;
> int order;
> + int i;
>
> - size = ALIGN(size, mem->page_size);
> - order = pci_epc_mem_get_order(mem, size);
> + for (i = 0; i < epc->mem_windows; i++) {
> + mem = epc->mem[i];
> + size = ALIGN(size, mem->page_size);
> + order = pci_epc_mem_get_order(mem, size);
> +
> + pageno = bitmap_find_free_region(mem->bitmap, mem->pages,
> + order);
> + if (pageno >= 0)
> + break;
> + }
>
> - pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
> if (pageno < 0)
> return NULL;
>
> - *phys_addr = mem->phys_base + ((phys_addr_t)pageno << page_shift);
> + page_shift = ilog2(mem->page_size);
> + *phys_addr = mem->window.phys_base +
> + ((phys_addr_t)pageno << page_shift);
> virt_addr = ioremap(*phys_addr, size);
> if (!virt_addr)
> bitmap_release_region(mem->bitmap, pageno, order);
> @@ -143,6 +182,22 @@ void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
> }
> EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
>
> +struct pci_epc_mem *pci_epc_get_matching_window(struct pci_epc *epc,
> + phys_addr_t phys_addr)
> +{
> + struct pci_epc_mem *mem;
> + int i;
> +
> + for (i = 0; i < epc->mem_windows; i++) {
> + mem = epc->mem[i];
> +
> + if (mem->window.phys_base == phys_addr)
> + return mem;

This will work only if the phys_addr is same as start of windows base.
This need not be true for all the platforms and will fail for all the
allocations except the first allocation.

Thanks
Kishon

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