Re: [v2 2/6] pci: endpoint: add support to handle features of outbound memory

[Kishon Vijay Abraham I]

Hi Prabhakar,

On 18/12/19 10:53 PM, Lad, Prabhakar wrote:
> Hi Kishon,
> 
> On Mon, Dec 16, 2019 at 11:34 AM Kishon Vijay Abraham I <kishon@xxxxxx> wrote:
>>
>> Hi Prabhakar,
>>
>> On 13/12/19 2:17 pm,  wrote:
>>> From: "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
>>>
>>> rcar pcie controller has support to map multiple memory regions
>>> for mapping the outbound memory in local system, this feature
>>> inspires to add support for handling such features in endpoint
>>> framework. similar features exists on other controllers where
>>> outbound regions can be specifically used for low/high priority
>>> transactions, and regions can be flagged and used for allocation
>>> of large/small memory allocations.
>>> This patch adds support to handle such features, where the
>>> properties described for outbound regions are used whenever a
>>> request to memory is made.
>>>
>>> Signed-off-by: Lad, Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
>>> ---
>>>   drivers/pci/controller/dwc/pcie-designware-ep.c |  30 ++--
>>>   drivers/pci/controller/pcie-cadence-ep.c        |  11 +-
>>>   drivers/pci/controller/pcie-rockchip-ep.c       |  13 +-
>>>   drivers/pci/endpoint/functions/pci-epf-test.c   |  47 ++++--
>>>   drivers/pci/endpoint/pci-epc-core.c             |   7 +-
>>>   drivers/pci/endpoint/pci-epc-mem.c              | 216 +++++++++++++++++++-----
>>>   include/linux/pci-epc.h                         |  72 ++++++--
>>>   7 files changed, 307 insertions(+), 89 deletions(-)
>>>
>>> diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
>>> index 3dd2e26..be6aa94 100644
>>> --- a/drivers/pci/controller/dwc/pcie-designware-ep.c
>>> +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
>>> @@ -195,7 +195,7 @@ static void dw_pcie_ep_unmap_addr(struct pci_epc *epc, u8 func_no,
>>>   }
>>>
>>>   static int dw_pcie_ep_map_addr(struct pci_epc *epc, u8 func_no,
>>> -                            phys_addr_t addr,
>>> +                            phys_addr_t addr, int window,
>>>                              u64 pci_addr, size_t size)
>>>   {
>>>       int ret;
>>> @@ -367,6 +367,7 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>       unsigned int aligned_offset;
>>>       u16 msg_ctrl, msg_data;
>>>       u32 msg_addr_lower, msg_addr_upper, reg;
>>> +     int window = PCI_EPC_DEFAULT_WINDOW;
>>>       u64 msg_addr;
>>>       bool has_upper;
>>>       int ret;
>>> @@ -390,11 +391,11 @@ int dw_pcie_ep_raise_msi_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>               reg = ep->msi_cap + PCI_MSI_DATA_32;
>>>               msg_data = dw_pcie_readw_dbi(pci, reg);
>>>       }
>>> -     aligned_offset = msg_addr_lower & (epc->mem->page_size - 1);
>>> +     aligned_offset = msg_addr_lower & (epc->mem[window]->page_size - 1);
>>>       msg_addr = ((u64)msg_addr_upper) << 32 |
>>>                       (msg_addr_lower & ~aligned_offset);
>>> -     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, msg_addr,
>>> -                               epc->mem->page_size);
>>> +     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, window,
>>> +                               msg_addr, epc->mem[window]->page_size);
>>>       if (ret)
>>>               return ret;
>>>
>>> @@ -416,6 +417,7 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>       u32 reg, msg_data, vec_ctrl;
>>>       u64 tbl_addr, msg_addr, reg_u64;
>>>       void __iomem *msix_tbl;
>>> +     int window = PCI_EPC_DEFAULT_WINDOW;
>>>       int ret;
>>>
>>>       reg = ep->msix_cap + PCI_MSIX_TABLE;
>>> @@ -452,8 +454,8 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>               return -EPERM;
>>>       }
>>>
>>> -     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, msg_addr,
>>> -                               epc->mem->page_size);
>>> +     ret = dw_pcie_ep_map_addr(epc, func_no, ep->msi_mem_phys, window,
>>> +                               msg_addr, epc->mem[window]->page_size);
>>>       if (ret)
>>>               return ret;
>>>
>>> @@ -466,10 +468,11 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
>>>
>>>   void dw_pcie_ep_exit(struct dw_pcie_ep *ep)
>>>   {
>>> +     int window = PCI_EPC_DEFAULT_WINDOW;
>>>       struct pci_epc *epc = ep->epc;
>>>
>>>       pci_epc_mem_free_addr(epc, ep->msi_mem_phys, ep->msi_mem,
>>> -                           epc->mem->page_size);
>>> +                           epc->mem[window]->page_size);
>>>
>>>       pci_epc_mem_exit(epc);
>>>   }
>>> @@ -499,9 +502,12 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>>>       u32 reg;
>>>       void *addr;
>>>       u8 hdr_type;
>>> +     int window;
>>>       unsigned int nbars;
>>>       unsigned int offset;
>>>       struct pci_epc *epc;
>>> +     size_t msi_page_size;
>>> +     struct pci_epc_mem_window mem_window;
>>>       struct dw_pcie *pci = to_dw_pcie_from_ep(ep);
>>>       struct device *dev = pci->dev;
>>>       struct device_node *np = dev->of_node;
>>> @@ -574,15 +580,17 @@ int dw_pcie_ep_init(struct dw_pcie_ep *ep)
>>>       if (ret < 0)
>>>               epc->max_functions = 1;
>>>
>>> -     ret = __pci_epc_mem_init(epc, ep->phys_base, ep->addr_size,
>>> -                              ep->page_size);
>>> +     mem_window.phys_base = ep->phys_base;
>>> +     mem_window.size = ep->addr_size;
>>> +     ret = __pci_epc_mem_init(epc, &mem_window, 1, ep->page_size);
>>>       if (ret < 0) {
>>>               dev_err(dev, "Failed to initialize address space\n");
>>>               return ret;
>>>       }
>>>
>>> -     ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys,
>>> -                                          epc->mem->page_size);
>>> +     msi_page_size = epc->mem[PCI_EPC_DEFAULT_WINDOW]->page_size;
>>> +     ep->msi_mem = pci_epc_mem_alloc_addr(epc, &ep->msi_mem_phys, &window,
>>> +                                          msi_page_size, 0x0);
>>>       if (!ep->msi_mem) {
>>>               dev_err(dev, "Failed to reserve memory for MSI/MSI-X\n");
>>>               return -ENOMEM;
>>> diff --git a/drivers/pci/controller/pcie-cadence-ep.c b/drivers/pci/controller/pcie-cadence-ep.c
>>> index def7820..2410706 100644
>>> --- a/drivers/pci/controller/pcie-cadence-ep.c
>>> +++ b/drivers/pci/controller/pcie-cadence-ep.c
>>> @@ -172,7 +172,7 @@ static void cdns_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
>>>   }
>>>
>>>   static int cdns_pcie_ep_map_addr(struct pci_epc *epc, u8 fn, phys_addr_t addr,
>>> -                              u64 pci_addr, size_t size)
>>> +                              int window, u64 pci_addr, size_t size)
>>>   {
>>>       struct cdns_pcie_ep *ep = epc_get_drvdata(epc);
>>>       struct cdns_pcie *pcie = &ep->pcie;
>>> @@ -434,12 +434,14 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
>>>   {
>>>       struct device *dev = &pdev->dev;
>>>       struct device_node *np = dev->of_node;
>>> +     struct pci_epc_mem_window mem_window;
>>>       struct cdns_pcie_ep *ep;
>>>       struct cdns_pcie *pcie;
>>>       struct pci_epc *epc;
>>>       struct resource *res;
>>>       int ret;
>>>       int phy_count;
>>> +     int window;
>>>
>>>       ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
>>>       if (!ep)
>>> @@ -502,15 +504,16 @@ static int cdns_pcie_ep_probe(struct platform_device *pdev)
>>>       if (of_property_read_u8(np, "max-functions", &epc->max_functions) < 0)
>>>               epc->max_functions = 1;
>>>
>>> -     ret = pci_epc_mem_init(epc, pcie->mem_res->start,
>>> -                            resource_size(pcie->mem_res));
>>> +     mem_window.phys_base = pcie->mem_res->start;
>>> +     mem_window.size = resource_size(pcie->mem_res);
>>> +     ret = pci_epc_mem_init(epc, &mem_window, 1);
>>>       if (ret < 0) {
>>>               dev_err(dev, "failed to initialize the memory space\n");
>>>               goto err_init;
>>>       }
>>>
>>>       ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
>>> -                                               SZ_128K);
>>> +                                               &window, SZ_128K, 0x0);
>>>       if (!ep->irq_cpu_addr) {
>>>               dev_err(dev, "failed to reserve memory space for MSI\n");
>>>               ret = -ENOMEM;
>>> diff --git a/drivers/pci/controller/pcie-rockchip-ep.c b/drivers/pci/controller/pcie-rockchip-ep.c
>>> index d743b0a..828052c 100644
>>> --- a/drivers/pci/controller/pcie-rockchip-ep.c
>>> +++ b/drivers/pci/controller/pcie-rockchip-ep.c
>>> @@ -256,8 +256,8 @@ static void rockchip_pcie_ep_clear_bar(struct pci_epc *epc, u8 fn,
>>>   }
>>>
>>>   static int rockchip_pcie_ep_map_addr(struct pci_epc *epc, u8 fn,
>>> -                                  phys_addr_t addr, u64 pci_addr,
>>> -                                  size_t size)
>>> +                                  phys_addr_t addr, int window,
>>> +                                  u64 pci_addr, size_t size)
>>>   {
>>>       struct rockchip_pcie_ep *ep = epc_get_drvdata(epc);
>>>       struct rockchip_pcie *pcie = &ep->rockchip;
>>> @@ -562,11 +562,13 @@ static const struct of_device_id rockchip_pcie_ep_of_match[] = {
>>>
>>>   static int rockchip_pcie_ep_probe(struct platform_device *pdev)
>>>   {
>>> +     struct pci_epc_mem_window mem_window;
>>>       struct device *dev = &pdev->dev;
>>>       struct rockchip_pcie_ep *ep;
>>>       struct rockchip_pcie *rockchip;
>>>       struct pci_epc *epc;
>>>       size_t max_regions;
>>> +     int window;
>>>       int err;
>>>
>>>       ep = devm_kzalloc(dev, sizeof(*ep), GFP_KERNEL);
>>> @@ -614,15 +616,16 @@ static int rockchip_pcie_ep_probe(struct platform_device *pdev)
>>>       /* Only enable function 0 by default */
>>>       rockchip_pcie_write(rockchip, BIT(0), PCIE_CORE_PHY_FUNC_CFG);
>>>
>>> -     err = pci_epc_mem_init(epc, rockchip->mem_res->start,
>>> -                            resource_size(rockchip->mem_res));
>>> +     mem_window.phys_base = rockchip->mem_res->start;
>>> +     mem_window.size = resource_size(rockchip->mem_res);
>>> +     err = pci_epc_mem_init(epc, &mem_window, 1);
>>>       if (err < 0) {
>>>               dev_err(dev, "failed to initialize the memory space\n");
>>>               goto err_uninit_port;
>>>       }
>>>
>>>       ep->irq_cpu_addr = pci_epc_mem_alloc_addr(epc, &ep->irq_phys_addr,
>>> -                                               SZ_128K);
>>> +                                               &window, SZ_128K, 0x0);
>>>       if (!ep->irq_cpu_addr) {
>>>               dev_err(dev, "failed to reserve memory space for MSI\n");
>>>               err = -ENOMEM;
>>> diff --git a/drivers/pci/endpoint/functions/pci-epf-test.c b/drivers/pci/endpoint/functions/pci-epf-test.c
>>> index 1cfe368..4768d54 100644
>>> --- a/drivers/pci/endpoint/functions/pci-epf-test.c
>>> +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
>>> @@ -84,8 +84,14 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
>>>       struct pci_epc *epc = epf->epc;
>>>       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
>>>       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
>>> -
>>> -     src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
>>> +     int window;
>>> +
>>> +     src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr,
>>> +                                       &window, reg->size,
>>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>>>       if (!src_addr) {
>>>               dev_err(dev, "Failed to allocate source address\n");
>>>               reg->status = STATUS_SRC_ADDR_INVALID;
>>> @@ -93,15 +99,20 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
>>>               goto err;
>>>       }
>>>
>>> -     ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, reg->src_addr,
>>> -                            reg->size);
>>> +     ret = pci_epc_map_addr(epc, epf->func_no, src_phys_addr, window,
>>> +                            reg->src_addr, reg->size);
>>>       if (ret) {
>>>               dev_err(dev, "Failed to map source address\n");
>>>               reg->status = STATUS_SRC_ADDR_INVALID;
>>>               goto err_src_addr;
>>>       }
>>>
>>> -     dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr, reg->size);
>>> +     dst_addr = pci_epc_mem_alloc_addr(epc, &dst_phys_addr,
>>> +                                       &window, reg->size,
>>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>>>       if (!dst_addr) {
>>>               dev_err(dev, "Failed to allocate destination address\n");
>>>               reg->status = STATUS_DST_ADDR_INVALID;
>>> @@ -109,8 +120,8 @@ static int pci_epf_test_copy(struct pci_epf_test *epf_test)
>>>               goto err_src_map_addr;
>>>       }
>>>
>>> -     ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, reg->dst_addr,
>>> -                            reg->size);
>>> +     ret = pci_epc_map_addr(epc, epf->func_no, dst_phys_addr, window,
>>> +                            reg->dst_addr, reg->size);
>>>       if (ret) {
>>>               dev_err(dev, "Failed to map destination address\n");
>>>               reg->status = STATUS_DST_ADDR_INVALID;
>>> @@ -146,8 +157,13 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
>>>       struct pci_epc *epc = epf->epc;
>>>       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
>>>       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
>>> +     int window;
>>>
>>> -     src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
>>> +     src_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, &window, reg->size,
>>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>>>       if (!src_addr) {
>>>               dev_err(dev, "Failed to allocate address\n");
>>>               reg->status = STATUS_SRC_ADDR_INVALID;
>>> @@ -155,8 +171,8 @@ static int pci_epf_test_read(struct pci_epf_test *epf_test)
>>>               goto err;
>>>       }
>>>
>>> -     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->src_addr,
>>> -                            reg->size);
>>> +     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, window,
>>> +                            reg->src_addr, reg->size);
>>>       if (ret) {
>>>               dev_err(dev, "Failed to map address\n");
>>>               reg->status = STATUS_SRC_ADDR_INVALID;
>>> @@ -193,13 +209,18 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
>>>       void __iomem *dst_addr;
>>>       void *buf;
>>>       phys_addr_t phys_addr;
>>> +     int window;
>>>       struct pci_epf *epf = epf_test->epf;
>>>       struct device *dev = &epf->dev;
>>>       struct pci_epc *epc = epf->epc;
>>>       enum pci_barno test_reg_bar = epf_test->test_reg_bar;
>>>       struct pci_epf_test_reg *reg = epf_test->reg[test_reg_bar];
>>>
>>> -     dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, reg->size);
>>> +     dst_addr = pci_epc_mem_alloc_addr(epc, &phys_addr, &window, reg->size,
>>> +                                       PCI_EPC_WINDOW_FLAG_LARGE_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_SMALL_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC |
>>> +                                       PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC);
>>>       if (!dst_addr) {
>>>               dev_err(dev, "Failed to allocate address\n");
>>>               reg->status = STATUS_DST_ADDR_INVALID;
>>> @@ -207,8 +228,8 @@ static int pci_epf_test_write(struct pci_epf_test *epf_test)
>>>               goto err;
>>>       }
>>>
>>> -     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, reg->dst_addr,
>>> -                            reg->size);
>>> +     ret = pci_epc_map_addr(epc, epf->func_no, phys_addr, window,
>>> +                            reg->dst_addr, reg->size);
>>>       if (ret) {
>>>               dev_err(dev, "Failed to map address\n");
>>>               reg->status = STATUS_DST_ADDR_INVALID;
>>> diff --git a/drivers/pci/endpoint/pci-epc-core.c b/drivers/pci/endpoint/pci-epc-core.c
>>> index 2091508..289c266 100644
>>> --- a/drivers/pci/endpoint/pci-epc-core.c
>>> +++ b/drivers/pci/endpoint/pci-epc-core.c
>>> @@ -358,13 +358,15 @@ EXPORT_SYMBOL_GPL(pci_epc_unmap_addr);
>>>    * @epc: the EPC device on which address is allocated
>>>    * @func_no: the endpoint function number in the EPC device
>>>    * @phys_addr: physical address of the local system
>>> + * @window: index to the window region where PCI address will be mapped
>>>    * @pci_addr: PCI address to which the physical address should be mapped
>>>    * @size: the size of the allocation
>>>    *
>>>    * Invoke to map CPU address with PCI address.
>>>    */
>>>   int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
>>> -                  phys_addr_t phys_addr, u64 pci_addr, size_t size)
>>> +                  phys_addr_t phys_addr, int window,
>>> +                  u64 pci_addr, size_t size)
>>>   {
>>>       int ret;
>>>       unsigned long flags;
>>> @@ -376,7 +378,8 @@ int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
>>>               return 0;
>>>
>>>       spin_lock_irqsave(&epc->lock, flags);
>>> -     ret = epc->ops->map_addr(epc, func_no, phys_addr, pci_addr, size);
>>> +     ret = epc->ops->map_addr(epc, func_no, phys_addr,
>>> +                              window, pci_addr, size);
>>>       spin_unlock_irqrestore(&epc->lock, flags);
>>>
>>>       return ret;
>>> diff --git a/drivers/pci/endpoint/pci-epc-mem.c b/drivers/pci/endpoint/pci-epc-mem.c
>>> index 2bf8bd1..4b610cd 100644
>>> --- a/drivers/pci/endpoint/pci-epc-mem.c
>>> +++ b/drivers/pci/endpoint/pci-epc-mem.c
>>> @@ -39,56 +39,78 @@ 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
>>> + * @num_windows: number of windows device supports
>>>    * @page_size: size of each page
>>>    *
>>>    * 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, size_t page_size)
>>>   {
>>> -     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;
>>>       int bitmap_size;
>>> +     int pages;
>>> +     int ret;
>>> +     int i;
>>> +
>>> +     epc->mem_windows = 0;
>>> +
>>> +     if (!windows)
>>> +             return -EINVAL;
>>> +
>>> +     if (num_windows <= 0)
>>> +             return -EINVAL;
>>>
>>>       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;
>>> -     }
>>> +     epc->mem = kcalloc(num_windows, sizeof(*mem), GFP_KERNEL);
>>> +     if (!epc->mem)
>>> +             return -EINVAL;
>>>
>>> -     bitmap = kzalloc(bitmap_size, GFP_KERNEL);
>>> -     if (!bitmap) {
>>> -             ret = -ENOMEM;
>>> -             goto err_mem;
>>> -     }
>>> +     for (i = 0; i < num_windows; i++) {
>>> +             pages = windows[i].phys_base >> 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;
>>> +             mem = kzalloc(sizeof(*mem), GFP_KERNEL);
>>> +             if (!mem) {
>>> +                     ret = -ENOMEM;
>>> +                     goto err_mem;
>>> +             }
>>>
>>> -     epc->mem = 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;
>>> +             mem->window.map_size = 0;
>>> +             mem->window.flags = windows[i].flags;
>>> +
>>> +             epc->mem[i] = mem;
>>> +     }
>>> +     epc->mem_windows = num_windows;
>>>
>>>       return 0;
>>>
>>>   err_mem:
>>> -     kfree(mem);
>>> +     for (; i >= 0; i--) {
>>> +             kfree(mem->bitmap);
>>> +             kfree(epc->mem[i]);
>>> +     }
>>> +     kfree(epc->mem);
>>>
>>> -err:
>>> -return ret;
>>> +     return ret;
>>>   }
>>>   EXPORT_SYMBOL_GPL(__pci_epc_mem_init);
>>>
>>> @@ -101,48 +123,152 @@ 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(epc->mem[i]);
>>> +     }
>>> +     kfree(epc->mem);
>>>
>>>       epc->mem = NULL;
>>> -     kfree(mem->bitmap);
>>> -     kfree(mem);
>>> +     epc->mem_windows = 0;
>>>   }
>>>   EXPORT_SYMBOL_GPL(pci_epc_mem_exit);
>>>
>>> +static int pci_epc_find_best_fit_window(struct pci_epc *epc, size_t size,
>>> +                                     u32 flags)
>>> +{
>>> +     size_t window_least_size = 0;
>>> +     int best_fit_window = -1;
>>> +     struct pci_epc_mem *mem;
>>> +     size_t actual_size;
>>> +     size_t avail_size;
>>> +     u32 win_flags;
>>> +     int i;
>>> +
>>> +     for (i = 0; i < epc->mem_windows; i++) {
>>> +             mem = epc->mem[i];
>>> +             win_flags = mem->window.flags;
>>> +
>>> +             actual_size = ALIGN(size, mem->page_size);
>>> +             avail_size = mem->window.size - mem->window.map_size;
>>> +
>>> +             if (win_flags == 0x0) {
>>> +                     if (best_fit_window == -1) {
>>> +                             if (actual_size <= avail_size) {
>>> +                                     best_fit_window = i;
>>> +                                     window_least_size = mem->window.size;
>>> +                             }
>>> +                     } else {
>>> +                             if (actual_size <= avail_size &&
>>> +                                 mem->window.size < window_least_size) {
>>> +                                     best_fit_window = i;
>>> +                                     window_least_size = mem->window.size;
>>> +                             }
>>> +                     }
>>> +             } else {
>>> +                     if (mem->window.map_size &&
>>> +                         (win_flags | PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC))
>>> +                             continue;
>>> +
>>> +                     if (!(win_flags | flags))
>>> +                             continue;
>>> +
>>> +                     if (best_fit_window == -1) {
>>> +                             if (actual_size <= avail_size) {
>>> +                                     best_fit_window = i;
>>> +                                     window_least_size = mem->window.size;
>>> +                             }
>>> +                     } else {
>>> +                             if (actual_size <= avail_size &&
>>> +                                 mem->window.size < window_least_size) {
>>> +                                     best_fit_window = i;
>>> +                                     window_least_size = mem->window.size;
>>> +                             }
>>> +                     }
>>> +             }
>>> +     }
>>> +
>>> +     return best_fit_window;
>>> +}
>>> +
>>>   /**
>>>    * pci_epc_mem_alloc_addr() - allocate memory address from EPC addr space
>>>    * @epc: the EPC device on which memory has to be allocated
>>>    * @phys_addr: populate the allocated physical address here
>>> + * @window: populate the window here which will be used to map PCI address
>>>    * @size: the size of the address space that has to be allocated
>>> + * @flags: look for window as requested in flags
>>>    *
>>>    * Invoke to allocate memory address from the EPC address space. This
>>>    * is usually done to map the remote RC address into the local system.
>>>    */
>>>   void __iomem *pci_epc_mem_alloc_addr(struct pci_epc *epc,
>>> -                                  phys_addr_t *phys_addr, size_t size)
>>> +                                  phys_addr_t *phys_addr,
>>> +                                  int *window, size_t size, uint32_t flags)
>>>   {
>>> +     int best_fit = PCI_EPC_DEFAULT_WINDOW;
>>> +     void __iomem *virt_addr = NULL;
>>> +     struct pci_epc_mem *mem;
>>> +     unsigned int page_shift;
>>>       int pageno;
>>> -     void __iomem *virt_addr;
>>> -     struct pci_epc_mem *mem = epc->mem;
>>> -     unsigned int page_shift = ilog2(mem->page_size);
>>>       int order;
>>>
>>> +     if (epc->mem_windows <= 0)
>>> +             return NULL;
>>> +
>>> +     if (epc->mem_windows > 1) {
>>> +             best_fit = pci_epc_find_best_fit_window(epc, size, flags);
>>> +             if (best_fit < 0)
>>> +                     return NULL;
>>> +     }
>>> +
>>> +     mem = epc->mem[best_fit];
>>>       size = ALIGN(size, mem->page_size);
>>> +     if (size > (mem->window.size - mem->window.map_size))
>>> +             return NULL;
>>> +     page_shift = ilog2(mem->page_size);
>>>       order = pci_epc_mem_get_order(mem, size);
>>>
>>>       pageno = bitmap_find_free_region(mem->bitmap, mem->pages, order);
>>>       if (pageno < 0)
>>>               return NULL;
>>>
>>> -     *phys_addr = mem->phys_base + (pageno << page_shift);
>>> +     *phys_addr = mem->window.phys_base + (pageno << page_shift);
>>>       virt_addr = ioremap(*phys_addr, size);
>>> -     if (!virt_addr)
>>> +     if (!virt_addr) {
>>>               bitmap_release_region(mem->bitmap, pageno, order);
>>> +     } else {
>>> +             mem->window.map_size += size;
>>> +             *window = best_fit;
>>> +     }
>>>
>>>       return virt_addr;
>>>   }
>>>   EXPORT_SYMBOL_GPL(pci_epc_mem_alloc_addr);
>>>
>>> +static int 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 i;
>>> +     }
>>> +
>>> +     return -EINVAL;
>>> +}
>>> +
>>>   /**
>>>    * pci_epc_mem_free_addr() - free the allocated memory address
>>>    * @epc: the EPC device on which memory was allocated
>>> @@ -155,16 +281,26 @@ 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;
>>> +     int window = 0;
>>>       int pageno;
>>> -     struct pci_epc_mem *mem = epc->mem;
>>> -     unsigned int page_shift = ilog2(mem->page_size);
>>>       int order;
>>>
>>> +     if (epc->mem_windows > 1) {
>>> +             window = pci_epc_get_matching_window(epc, phys_addr);
>>> +             if (window < 0)
>>> +                     return;
>>> +     }
>>> +
>>> +     mem = epc->mem[window];
>>> +     page_shift = ilog2(mem->page_size);
>>>       iounmap(virt_addr);
>>> -     pageno = (phys_addr - mem->phys_base) >> page_shift;
>>> +     pageno = (phys_addr - mem->window.phys_base) >> page_shift;
>>>       size = ALIGN(size, mem->page_size);
>>>       order = pci_epc_mem_get_order(mem, size);
>>>       bitmap_release_region(mem->bitmap, pageno, order);
>>> +     mem->window.map_size -= size;
>>>   }
>>>   EXPORT_SYMBOL_GPL(pci_epc_mem_free_addr);
>>>
>>> diff --git a/include/linux/pci-epc.h b/include/linux/pci-epc.h
>>> index f641bad..bee6f65 100644
>>> --- a/include/linux/pci-epc.h
>>> +++ b/include/linux/pci-epc.h
>>> @@ -48,7 +48,8 @@ struct pci_epc_ops {
>>>       void    (*clear_bar)(struct pci_epc *epc, u8 func_no,
>>>                            struct pci_epf_bar *epf_bar);
>>>       int     (*map_addr)(struct pci_epc *epc, u8 func_no,
>>> -                         phys_addr_t addr, u64 pci_addr, size_t size);
>>> +                         phys_addr_t addr, int window,
>>> +                         u64 pci_addr, size_t size);
>>>       void    (*unmap_addr)(struct pci_epc *epc, u8 func_no,
>>>                             phys_addr_t addr);
>>>       int     (*set_msi)(struct pci_epc *epc, u8 func_no, u8 interrupts);
>>> @@ -64,17 +65,57 @@ struct pci_epc_ops {
>>>       struct module *owner;
>>>   };
>>>
>>> +#define PCI_EPC_DEFAULT_WINDOW               0
>>> +
>>> +/**
>>> + * enum pci_epc_window_flags - flags info for pci_epc_mem_window
>>> + *
>>> + * This enum defines how the endpoint controller window should be used
>>> + * for allocations.
>>> + *
>>> + * @PCI_EPC_WINDOW_FLAG_MULTI_ALLOC: Indicates multiple chunks of memory can be
>>> + *                                allocated from same window
>>> + * @PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC: Indicates only single memory allocation
>>> + *                                    is possible on the window
>>
>> Instead of NON_MULTI_ALLOC, we could simply have different page_size for
>> different windows. For a platform that doesn't allow multiple alloc,
>> page size will be equal to the window size.
>>
> I would still prefer this flag and not go with page size = window size
> as we could allocate unnecessary memory

Nor sure I understand you here. If you have
PCI_EPC_WINDOW_FLAG_NON_MULTI_ALLOC, wouldn't it mean, you cannot have
more than 1 allocation in the entire window. Setting page size same as
window size will also mean the same thing.
> that might not be used and also the window sizes might be too large.

IMHO We could still have flags to provide a type for a window and
directing the allocation to a particular window with a type. But
at-least for the use case that you are trying to solve, it's simpler to
have page_size = window_size and the allocation algorithm need not change.

Thanks
Kishon