Re: [PATCH 2/5] pci: endpoint: add support to handle multiple base for mapping outbound memory

[Kishon Vijay Abraham I]

Hi,

On 28/11/19 2:51 am, Lad, Prabhakar wrote:
> Hi Kishon,
>
> Thank you for the review.
>
> On Wed, Nov 27, 2019 at 5:15 AM Kishon Vijay Abraham I <kishon@xxxxxx> wrote:
> > Hi Prabhakar,
> >
> > On 07/11/19 1:06 AM, Lad Prabhakar 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 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.
> > >
> > > Signed-off-by: Lad, Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > > Cc: <linux-rockchip@xxxxxxxxxxxxxxxxxxx>
> > > Cc: Shawn Lin <shawn.lin@xxxxxxxxxxxxxx>
> > > Cc: Heiko Stuebner <heiko@xxxxxxxxx>
> > > Cc: Tom Joseph <tjoseph@xxxxxxxxxxx>
> > > Cc: Jingoo Han <jingoohan1@xxxxxxxxx>
> > > Cc: Gustavo Pimentel <gustavo.pimentel@xxxxxxxxxxxx>
> > > ---
> > >   .../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
> >
> > struct pci_epc_mem_window is missing here.
> oops my bad will fix that.
>
> > >    * @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;
> >
> > Assume I have two mem regions, first region is of size 128MB and the second
> > region is of size 4GB. If there is a allocation request for 4GB, will the
> > allocation succeed?
> yes it would succeed, the pci_epc_find_best_fit_window() would get the
> corresponding window.

Can you step through the algo again? pci_epc_find_best_fit_window() will 
return the first region which is of size 128MB.

Thanks
Kishon