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

["Lad, Prabhakar" <prabhakar.csengg@gmail.com>]

Hi Kishon,

On Mon, Dec 16, 2019 at 11:34 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
>
> Hi Prabhakar,
>
> On 13/12/19 2:17 pm,  wrote:
> > From: "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>
> >
> > 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@bp.renesas.com>
> > ---
> >   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
that might not be used and also the window sizes might be too large.

> > + * @PCI_EPC_WINDOW_FLAG_LARGE_ALLOC: Window is used for large memory allocation
> > + * @PCI_EPC_WINDOW_FLAG_SMALL_ALLOC: Window is used for small memory allocation
> > + * @PCI_EPC_WINDOW_FLAG_HIGH_PRI_ALLOC: Window is used for high priority data
> > + *                                   transfers
> > + * @PCI_EPC_WINDOW_FLAG_LOW_PRI_ALLOC: Window is used for low priority data
> > + *                                  transfers
>
> Let's defer adding these flags until a platform actually starts to use this.
>
sure will drop the above.

Cheers,
--Prabhakar

> Thanks
> Kishon