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References: <20191106193609.19645-1-prabhakar.mahadev-lad.rj@bp.renesas.com>
 <20191106193609.19645-3-prabhakar.mahadev-lad.rj@bp.renesas.com> <51563ddf-381f-3290-d9c0-82eb23aaa674@ti.com>
In-Reply-To: <51563ddf-381f-3290-d9c0-82eb23aaa674@ti.com>
From:   "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Date:   Wed, 27 Nov 2019 21:28:14 +0000
Message-ID: <CA+V-a8uNQKVYHk-D3Q6ZftE9q3NfExXJu1vCuuGTSYcwK9xiNw@mail.gmail.com>
Subject: Re: [PATCH 2/5] pci: endpoint: add support to handle multiple base
 for mapping outbound memory
To:     Kishon Vijay Abraham I <kishon@ti.com>
Cc:     Bjorn Helgaas <bhelgaas@google.com>,
        Rob Herring <robh+dt@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Magnus Damm <magnus.damm@gmail.com>,
        Marek Vasut <marek.vasut+renesas@gmail.com>,
        Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
        linux-pci <linux-pci@vger.kernel.org>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Andrew Murray <andrew.murray@arm.com>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org>,
        LAK <linux-arm-kernel@lists.infradead.org>,
        Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
        Chris Paterson <Chris.Paterson2@renesas.com>,
        "Lad, Prabhakar" <prabhakar.mahadev-lad.rj@bp.renesas.com>,
        linux-rockchip@lists.infradead.org,
        Shawn Lin <shawn.lin@rock-chips.com>,
        Heiko Stuebner <heiko@sntech.de>,
        Tom Joseph <tjoseph@cadence.com>,
        Jingoo Han <jingoohan1@gmail.com>,
        Gustavo Pimentel <gustavo.pimentel@synopsys.com>
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Hi Kishon,

On Wed, Nov 27, 2019 at 6:06 AM Kishon Vijay Abraham I <kishon@ti.com> wrote:
>
> Hi Prabhakar,
>
> On 07/11/19 1:06 AM, Lad Prabhakar 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 multiple memory bases in
> > endpoint framework. In case of multiple memory regions only chunk
> > or complete region can be mapped and this window needs to be
> > passed to the controller driver.
>
> Wouldn't this result in lot of unused address and exhausting the memory regions
> quickly? I think we could have a "type" associated with each of these regions
> and smaller allocations could use one "type" and larger allocation could use a
> different "type"? For instance we allocate memory regions for MSI interrupt and
> for data transfer. We could use smaller allocations for MSI and larger
> allocations for data transfers.
>
> We could also extend the "type" for certain special requirements. For instance
> I've seen platforms which have dedicated address space for high priority data
> transfers (uses higher virtual channel numbers) and dedicated address space for
> low priority data transfers (uses lower virtual channel numbers).
>
> Here too we could give a special flag or type for higher priority address
> regions and different type for lower priority address. While allocating, the
> function drivers should provide a flag specifying the region where memory
> should be allocated.
>
agreed but in this controller if chunk is allocated from the window
this cannot be re-used
for further allocations, I haven't come across a where a window could
be used with multiple
chunks being allocated. so as you suggest I could extend the type to
have additional flag
which would indicate if window can be used for multiple chunk allocations.

> Can you add flags in struct pci_epc_mem_window and see how that comes out?
>
sure will do that.

Cheers,
--Prabhakar

> Thanks
> Kishon
>
> >
> > Signed-off-by: Lad, Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
> > Cc: <linux-rockchip@lists.infradead.org>
> > Cc: Shawn Lin <shawn.lin@rock-chips.com>
> > Cc: Heiko Stuebner <heiko@sntech.de>
> > Cc: Tom Joseph <tjoseph@cadence.com>
> > Cc: Jingoo Han <jingoohan1@gmail.com>
> > Cc: Gustavo Pimentel <gustavo.pimentel@synopsys.com>
> > ---
> >  .../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 |  29 +--
> >  drivers/pci/endpoint/pci-epc-core.c           |   7 +-
> >  drivers/pci/endpoint/pci-epc-mem.c            | 189 ++++++++++++++----
> >  include/linux/pci-epc.h                       |  43 ++--
> >  7 files changed, 234 insertions(+), 88 deletions(-)
> >
> > diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
> > index 3dd2e2697294..8d23c20b9afd 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);
> >       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 def7820cb824..7991b38a5350 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);
> >       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 d743b0a48988..d59e85c8d319 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);
> >       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 5d74f81ddfe4..475228011703 100644
> > --- a/drivers/pci/endpoint/functions/pci-epf-test.c
> > +++ b/drivers/pci/endpoint/functions/pci-epf-test.c
> > @@ -84,8 +84,10 @@ 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];
> > +     int window;
> >
> > -     src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr, reg->size);
> > +     src_addr = pci_epc_mem_alloc_addr(epc, &src_phys_addr,
> > +                                       &window, reg->size);
> >       if (!src_addr) {
> >               dev_err(dev, "Failed to allocate source address\n");
> >               reg->status = STATUS_SRC_ADDR_INVALID;
> > @@ -93,15 +95,16 @@ 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);
> >       if (!dst_addr) {
> >               dev_err(dev, "Failed to allocate destination address\n");
> >               reg->status = STATUS_DST_ADDR_INVALID;
> > @@ -109,8 +112,8 @@ 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 +149,9 @@ 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);
> >       if (!src_addr) {
> >               dev_err(dev, "Failed to allocate address\n");
> >               reg->status = STATUS_SRC_ADDR_INVALID;
> > @@ -155,8 +159,8 @@ 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 +197,14 @@ 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);
> >       if (!dst_addr) {
> >               dev_err(dev, "Failed to allocate address\n");
> >               reg->status = STATUS_DST_ADDR_INVALID;
> > @@ -207,8 +212,8 @@ 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 2091508c1620..289c266c2d90 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 d2b174ce15de..c955f2c97944 100644
> > --- a/drivers/pci/endpoint/pci-epc-mem.c
> > +++ b/drivers/pci/endpoint/pci-epc-mem.c
> > @@ -39,56 +39,77 @@ 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;
> > +
> > +             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 +122,126 @@ 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)
> > +{
> > +     size_t window_least_size = 0;
> > +     int best_fit_window = -1;
> > +     struct pci_epc_mem *mem;
> > +     size_t actual_size;
> > +     int i;
> > +
> > +     for (i = 0; i < epc->mem_windows; i++) {
> > +             mem = epc->mem[i];
> > +
> > +             /* if chunk from this region is already used skip it */
> > +             if (mem->window.map_size)
> > +                     continue;
> > +
> > +             actual_size = ALIGN(size, mem->page_size);
> > +
> > +             if (best_fit_window == -1) {
> > +                     best_fit_window = i;
> > +                     window_least_size = mem->window.size;
> > +             } else {
> > +                     if (actual_size <= mem->window.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
> >   *
> >   * 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)
> >  {
> > +     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);
> > +             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 + ((phys_addr_t)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 +254,26 @@ 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 56f1846b9d39..5e86d22dd5c5 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 +65,28 @@ struct pci_epc_ops {
> >       struct module *owner;
> >  };
> >
> > +#define PCI_EPC_DEFAULT_WINDOW               0
> > +
> > +/**
> > + * 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
> > + */
> > +struct pci_epc_mem_window {
> > +     phys_addr_t     phys_base;
> > +     size_t          size;
> > +     size_t          map_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
> > + * @pages: number of bits representing the address region
> >   */
> >  struct pci_epc_mem {
> > -     phys_addr_t     phys_base;
> > -     size_t          size;
> > +     struct pci_epc_mem_window window;
> >       unsigned long   *bitmap;
> >       size_t          page_size;
> >       int             pages;
> > @@ -85,7 +97,8 @@ struct pci_epc_mem {
> >   * @dev: PCI EPC device
> >   * @pci_epf: list of endpoint functions present in this EPC device
> >   * @ops: function pointers for performing endpoint operations
> > - * @mem: address space of the endpoint controller
> > + * @mem: array of address space of the endpoint controller
> > + * @mem_windows: number of windows supported by device
> >   * @max_functions: max number of functions that can be configured in this EPC
> >   * @group: configfs group representing the PCI EPC device
> >   * @lock: spinlock to protect pci_epc ops
> > @@ -94,7 +107,8 @@ struct pci_epc {
> >       struct device                   dev;
> >       struct list_head                pci_epf;
> >       const struct pci_epc_ops        *ops;
> > -     struct pci_epc_mem              *mem;
> > +     struct pci_epc_mem              **mem;
> > +     int                             mem_windows;
> >       u8                              max_functions;
> >       struct config_group             *group;
> >       /* spinlock to protect against concurrent access of EP controller */
> > @@ -128,8 +142,8 @@ struct pci_epc_features {
> >  #define devm_pci_epc_create(dev, ops)    \
> >               __devm_pci_epc_create((dev), (ops), THIS_MODULE)
> >
> > -#define pci_epc_mem_init(epc, phys_addr, size)       \
> > -             __pci_epc_mem_init((epc), (phys_addr), (size), PAGE_SIZE)
> > +#define pci_epc_mem_init(epc, windows, num_windows)  \
> > +             __pci_epc_mem_init((epc), windows, num_windows, PAGE_SIZE)
> >
> >  static inline void epc_set_drvdata(struct pci_epc *epc, void *data)
> >  {
> > @@ -159,7 +173,7 @@ int pci_epc_set_bar(struct pci_epc *epc, u8 func_no,
> >  void pci_epc_clear_bar(struct pci_epc *epc, u8 func_no,
> >                      struct pci_epf_bar *epf_bar);
> >  int pci_epc_map_addr(struct pci_epc *epc, u8 func_no,
> > -                  phys_addr_t phys_addr,
> > +                  phys_addr_t phys_addr, int window,
> >                    u64 pci_addr, size_t size);
> >  void pci_epc_unmap_addr(struct pci_epc *epc, u8 func_no,
> >                       phys_addr_t phys_addr);
> > @@ -178,11 +192,12 @@ unsigned int pci_epc_get_first_free_bar(const struct pci_epc_features
> >  struct pci_epc *pci_epc_get(const char *epc_name);
> >  void pci_epc_put(struct pci_epc *epc);
> >
> > -int __pci_epc_mem_init(struct pci_epc *epc, phys_addr_t phys_addr, size_t size,
> > -                    size_t page_size);
> > +int __pci_epc_mem_init(struct pci_epc *epc, struct pci_epc_mem_window *window,
> > +                    int num_windows, size_t page_size);
> >  void pci_epc_mem_exit(struct pci_epc *epc);
> >  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);
> >  void pci_epc_mem_free_addr(struct pci_epc *epc, phys_addr_t phys_addr,
> >                          void __iomem *virt_addr, size_t size);
> >  #endif /* __LINUX_PCI_EPC_H */
> >