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Date: Fri, 24 Apr 2020 13:30:56 +0530
From: Kishon Vijay Abraham I <kishon@...com>
To: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
CC: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@....com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Rob Herring <robh+dt@...nel.org>,
Andrew Murray <amurray@...goodpenguin.co.uk>,
Tom Joseph <tjoseph@...ence.com>,
Jingoo Han <jingoohan1@...il.com>,
Gustavo Pimentel <gustavo.pimentel@...opsys.com>,
Marek Vasut <marek.vasut+renesas@...il.com>,
Shawn Lin <shawn.lin@...k-chips.com>,
Heiko Stuebner <heiko@...ech.de>,
Geert Uytterhoeven <geert@...ux-m68k.org>,
linux-pci <linux-pci@...r.kernel.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@...r.kernel.org>, LKML <linux-kernel@...r.kernel.org>,
Linux-Renesas <linux-renesas-soc@...r.kernel.org>,
"open list:ARM/Rockchip SoC..." <linux-rockchip@...ts.infradead.org>,
LAK <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v9 5/8] PCI: endpoint: Add support to handle multiple base
for mapping outbound memory
Hi Prabhakar,
On 4/24/2020 1:16 PM, Lad, Prabhakar wrote:
> Hi Kishon,
>
> Thank you for the review.
>
> On Fri, Apr 24, 2020 at 7:13 AM Kishon Vijay Abraham I <kishon@...com> wrote:
>>
>> 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@...renesas.com>
>>> ---
>>> .../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].
> This was suggested by Shimoda-san, as most of the current controller
> drivers support single region this pointer would be easier to access
> the region instead of adding #define EPC_DEFAULT_WINDOW 0 and
> accessing as epc->windows[EPC_DEFAULT_WINDOW];
>
>>> + 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.
>>
> Controllers supporting multiple windows create a list of supported
> regions (struct pci_epc_mem_window ) and pass a pointer to
> pci_epc_multi_mem_init(), hence this split.
Okay, thanks for clarifying.
Regards
Kishon
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