Re: [PATCH v9 5/8] PCI: endpoint: Add support to handle multiple base for mapping outbound memory

From: Kishon Vijay Abraham I
Date: Fri Apr 24 2020 - 02:14:25 EST

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Next in thread: Lad, Prabhakar: "Re: [PATCH v9 5/8] PCI: endpoint: Add support to handle multiple base for mapping outbound memory"
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Hi Prabhakar,

On 4/23/2020 11:52 PM, 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() initializes address space for endpoint
> controller which support single window and pci_epc_multi_mem_init()
> initializes multiple windows supported by endpoint controller.

Have a couple of clean-up comments. See below.
>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> ---
> .../pci/controller/dwc/pcie-designware-ep.c | 16 +-
> drivers/pci/endpoint/pci-epc-mem.c | 199 ++++++++++++------
> include/linux/pci-epc.h | 33 ++-
> 3 files changed, 170 insertions(+), 78 deletions(-)
>
.
.
<snip>
.
.
> diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
> index cdd1d3821249..a3466da2a16f 100644
> --- a/drivers/pci/endpoint/pci-epc-mem.c
> +++ b/drivers/pci/endpoint/pci-epc-mem.c
> @@ -23,7 +23,7 @@
> static int pci_epc_mem_get_order(struct pci_epc_mem *mem, size_t size)
> {
> int order;
> - unsigned int page_shift = ilog2(mem->page_size);
> + unsigned int page_shift = ilog2(mem->window.page_size);
>
> size--;
> size >>= page_shift;
> @@ -36,67 +36,95 @@ 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
> + * pci_epc_multi_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_multi_mem_init(struct pci_epc *epc,
> + struct pci_epc_mem_window *windows,
> + unsigned 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;
> + int pages;
> + int ret;
> + int i;
>
> - if (page_size < PAGE_SIZE)
> - page_size = PAGE_SIZE;
> + epc->num_windows = 0;
>
> - page_shift = ilog2(page_size);
> - pages = size >> page_shift;
> - bitmap_size = BITS_TO_LONGS(pages) * sizeof(long);
> + if (!windows || !num_windows)
> + return -EINVAL;
>
> - mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> - if (!mem) {
> - ret = -ENOMEM;
> - goto err;
> - }
> + epc->windows = kcalloc(num_windows, sizeof(*mem), GFP_KERNEL);
> + if (!epc->windows)
> + return -ENOMEM;
>
> - bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> - if (!bitmap) {
> - ret = -ENOMEM;
> - goto err_mem;
> - }
> + 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->bitmap = bitmap;
> - mem->phys_base = phys_base;
> - mem->page_size = page_size;
> - mem->pages = pages;
> - mem->size = size;
> - mutex_init(&mem->lock);
> + mem = kzalloc(sizeof(*mem), GFP_KERNEL);
> + if (!mem) {
> + ret = -ENOMEM;
> + i--;
> + goto err_mem;
> + }
>
> - epc->mem = mem;
> + bitmap = kzalloc(bitmap_size, GFP_KERNEL);
> + if (!bitmap) {
> + ret = -ENOMEM;
> + kfree(mem);
> + i--;
> + goto err_mem;
> + }
> +
> + mem->window.phys_base = windows[i].phys_base;
> + mem->window.size = windows[i].size;
> + mem->window.page_size = page_size;
> + mem->bitmap = bitmap;
> + mem->pages = pages;
> + mutex_init(&mem->lock);
> + epc->windows[i] = mem;
> + }
> +
> + epc->mem = epc->windows[0];

"mem" member of EPC looks unnecessary since that value is available at
epc->windows[0].
> + epc->num_windows = num_windows;
>
> return 0;
>
> err_mem:
> - kfree(mem);
> + for (; i >= 0; i--) {
> + mem = epc->windows[i];
> + kfree(mem->bitmap);
> + kfree(mem);
> + }
> + kfree(epc->windows);
>
> -err:
> -return ret;
> + return ret;
> }
> -EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
> +EXPORT_SYMBOL_GPL(pci_epc_multi_mem_init);
>
> int pci_epc_mem_init(struct pci_epc *epc, phys_addr_t base,
> size_t size, size_t page_size)
> {
> - return __pci_epc_mem_init(epc, base, size, page_size);
> + struct pci_epc_mem_window mem_window;
> +
> + mem_window.phys_base = base;
> + mem_window.size = size;
> + mem_window.page_size = page_size;
> +
> + return pci_epc_multi_mem_init(epc, &mem_window, 1);
> }
> EXPORT_SYMBOL_GPL(pci_epc_mem_init);
>
> @@ -109,11 +137,22 @@ 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->num_windows)
> + return;
> +
> + for (i = 0; i < epc->num_windows; i++) {
> + mem = epc->windows[i];
> + kfree(mem->bitmap);
> + kfree(mem);
> + }
> + kfree(epc->windows);
> +
> + epc->windows = NULL;
> epc->mem = NULL;
> - kfree(mem->bitmap);
> - kfree(mem);
> + epc->num_windows = 0;
> }
> EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
>
> @@ -129,31 +168,60 @@ 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 = NULL;
> - struct pci_epc_mem *mem = epc->mem;
> - unsigned int page_shift = ilog2(mem->page_size);
> + struct pci_epc_mem *mem;
> + unsigned int page_shift;
> + size_t align_size;
> + int pageno;
> int order;
> + int i;
>
> - size = ALIGN(size, mem->page_size);
> - order = pci_epc_mem_get_order(mem, size);
> -
> - mutex_lock(&mem->lock);
> - pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
> - if (pageno < 0)
> - goto ret;
> + for (i = 0; i < epc->num_windows; i++) {
> + mem = epc->windows[i];
> + mutex_lock(&mem->lock);
> + align_size = ALIGN(size, mem->window.page_size);
> + order = pci_epc_mem_get_order(mem, align_size);
>
> - *phys_addr = mem->phys_base + ((phys_addr_t)pageno << page_shift);
> - virt_addr = ioremap(*phys_addr, size);
> - if (!virt_addr)
> - bitmap_release_region(mem->bitmap, pageno, order);
> + pageno = bitmap_find_free_region(mem->bitmap, mem->pages,
> + order);
> + if (pageno >= 0) {
> + page_shift = ilog2(mem->window.page_size);
> + *phys_addr = mem->window.phys_base +
> + ((phys_addr_t)pageno << page_shift);
> + virt_addr = ioremap(*phys_addr, align_size);
> + if (!virt_addr) {
> + bitmap_release_region(mem->bitmap,
> + pageno, order);
> + mutex_unlock(&mem->lock);
> + continue;
> + }
> + mutex_unlock(&mem->lock);
> + return virt_addr;
> + }
> + mutex_unlock(&mem->lock);
> + }
>
> -ret:
> - mutex_unlock(&mem->lock);
> return virt_addr;
> }
> 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->num_windows; i++) {
> + mem = epc->windows[i];
> +
> + if (phys_addr >= mem->window.phys_base &&
> + phys_addr < (mem->window.phys_base + mem->window.size))
> + return mem;
> + }
> +
> + return NULL;
> +}
> +
> /**
> * pci_epc_mem_free_addr() - free the allocated memory address
> * @epc: the EPC device on which memory was allocated
> @@ -166,14 +234,23 @@ EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
> void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
> void __iomem *virt_addr, size_t size)
> {
> + struct pci_epc_mem *mem;
> + unsigned int page_shift;
> + size_t page_size;
> int pageno;
> - struct pci_epc_mem *mem = epc->mem;
> - unsigned int page_shift = ilog2(mem->page_size);
> int order;
>
> + mem = pci_epc_get_matching_window(epc, phys_addr);
> + if (!mem) {
> + pr_err("failed to get matching window\n");
> + return;
> + }
> +
> + page_size = mem->window.page_size;
> + page_shift = ilog2(page_size);
> iounmap(virt_addr);
> - pageno = (phys_addr - mem->phys_base) >> page_shift;
> - size = ALIGN(size, mem->page_size);
> + pageno = (phys_addr - mem->window.phys_base) >> page_shift;
> + size = ALIGN(size, page_size);
> order = pci_epc_mem_get_order(mem, size);
> mutex_lock(&mem->lock);
> bitmap_release_region(mem->bitmap, pageno, order);
> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
> index 5bc1de65849e..cc66bec8be90 100644
> --- a/include/linux/pci-epc.h
> +++ b/include/linux/pci-epc.h
> @@ -65,20 +65,28 @@ struct pci_epc_ops {
> struct module *owner;
> };
>
> +/**
> + * struct pci_epc_mem_window - address window of the endpoint controller
> + * @phys_base: physical base address of the PCI address window
> + * @size: the size of the PCI address window
> + * @page_size: size of each page
> + */
> +struct pci_epc_mem_window {
> + phys_addr_t phys_base;
> + size_t size;
> + size_t page_size;
> +};
> +
> /**
> * struct pci_epc_mem - address space of the endpoint controller
> - * @phys_base: physical base address of the PCI address space
> - * @size: the size of the PCI address space
> + * @window: address window of the endpoint controller
> * @bitmap: bitmap to manage the PCI address space
> * @pages: number of bits representing the address region
> - * @page_size: size of each page
> * @lock: mutex to protect bitmap
> */
> struct pci_epc_mem {
> - phys_addr_t phys_base;
> - size_t size;
> + struct pci_epc_mem_window window;

Don't see any additional value in moving phys_base, size, page_size to a new
structure and again including it here.

Thanks
Kishon

Next message: Christoph Hellwig: "Re: [PATCH v2] block: Limit number of items taken from the I/O scheduler in one go"
Previous message: David Gow: "[PATCH v7 5/5] mm: kasan: Do not panic if both panic_on_warn and kasan_multishot set"
In reply to: Yoshihiro Shimoda: "RE: [PATCH v9 5/8] PCI: endpoint: Add support to handle multiple base for mapping outbound memory"
Next in thread: Lad, Prabhakar: "Re: [PATCH v9 5/8] PCI: endpoint: Add support to handle multiple base for mapping outbound memory"
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