PCI/alpha: pci sysfs resources

This closes http://bugzilla.kernel.org/show_bug.cgi?id=10893
which is a showstopper for X development on alpha.

The generic HAVE_PCI_MMAP code (drivers/pci-sysfs.c) is not
very useful since we have to deal with three different types
of MMIO address spaces: sparse and dense mappings for old
ev4/ev5 machines and "normal" 1:1 MMIO space (bwx) for ev56 and
later.
Also "write combine" mappings are meaningless on alpha - roughly
speaking, alpha does write combining, IO reordering and other
optimizations by default, unless user splits IO accesses
with memory barriers.

I think the cleanest way to deal with resource files on alpha
is to convert the default no-op pci_create_resource_files() and
pci_remove_resource_files() for !HAVE_PCI_MMAP case into __weak
functions and override them with alpha specific ones.

Another alpha hook is needed for "legacy_" resource files
to handle sparse addressing (pci_adjust_legacy_attr).

With the "standard" resourceN files on ev56/ev6 libpciaccess
works "out of the box". Handling of resourceN_sparse/resourceN_dense
files on older machines obviously requires some userland work.

Sparse/dense stuff has been tested on sx164 (pca56/pyxis, normally
uses bwx IO) with the kernel hacked into "cia compatible" mode.

Signed-off-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

2 files changed, 367 insertions, 1 deletions

diff --git a/arch/alpha/kernel/Makefile b/arch/alpha/kernel/Makefile
index b4697759a123..a427538252f8 100644
--- a/arch/alpha/kernel/Makefile
+++ b/arch/alpha/kernel/Makefile
@@ -12,7 +12,7 @@ obj-y    := entry.o traps.o process.o init_task.o osf_sys.o irq.o \
 
 obj-$(CONFIG_VGA_HOSE)  += console.o
 obj-$(CONFIG_SMP)       += smp.o
-obj-$(CONFIG_PCI)       += pci.o pci_iommu.o
+obj-$(CONFIG_PCI)       += pci.o pci_iommu.o pci-sysfs.o
 obj-$(CONFIG_SRM_ENV)   += srm_env.o
 obj-$(CONFIG_MODULES)   += module.o
 
diff --git a/arch/alpha/kernel/pci-sysfs.c b/arch/alpha/kernel/pci-sysfs.c
new file mode 100644
index 000000000000..6ea822e7f724
--- /dev/null
+++ b/arch/alpha/kernel/pci-sysfs.c
@@ -0,0 +1,366 @@
+/*
+ * arch/alpha/kernel/pci-sysfs.c
+ *
+ * Copyright (C) 2009 Ivan Kokshaysky
+ *
+ * Alpha PCI resource files.
+ *
+ * Loosely based on generic HAVE_PCI_MMAP implementation in
+ * drivers/pci/pci-sysfs.c
+ */
+
+#include <linux/sched.h>
+#include <linux/pci.h>
+
+static int hose_mmap_page_range(struct pci_controller *hose,
+                                struct vm_area_struct *vma,
+                                enum pci_mmap_state mmap_type, int sparse)
+{
+        unsigned long base;
+
+        if (mmap_type == pci_mmap_mem)
+                base = sparse ? hose->sparse_mem_base : hose->dense_mem_base;
+        else
+                base = sparse ? hose->sparse_io_base : hose->dense_io_base;
+
+        vma->vm_pgoff += base >> PAGE_SHIFT;
+        vma->vm_flags |= (VM_IO | VM_RESERVED);
+
+        return io_remap_pfn_range(vma, vma->vm_start, vma->vm_pgoff,
+                                  vma->vm_end - vma->vm_start,
+                                  vma->vm_page_prot);
+}
+
+static int __pci_mmap_fits(struct pci_dev *pdev, int num,
+                           struct vm_area_struct *vma, int sparse)
+{
+        unsigned long nr, start, size;
+        int shift = sparse ? 5 : 0;
+
+        nr = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+        start = vma->vm_pgoff;
+        size = ((pci_resource_len(pdev, num) - 1) >> (PAGE_SHIFT - shift)) + 1;
+
+        if (start < size && size - start >= nr)
+                return 1;
+        WARN(1, "process \"%s\" tried to map%s 0x%08lx-0x%08lx on %s BAR %d "
+                "(size 0x%08lx)\n",
+                current->comm, sparse ? " sparse" : "", start, start + nr,
+                pci_name(pdev), num, size);
+        return 0;
+}
+
+/**
+ * pci_mmap_resource - map a PCI resource into user memory space
+ * @kobj: kobject for mapping
+ * @attr: struct bin_attribute for the file being mapped
+ * @vma: struct vm_area_struct passed into the mmap
+ * @sparse: address space type
+ *
+ * Use the bus mapping routines to map a PCI resource into userspace.
+ */
+static int pci_mmap_resource(struct kobject *kobj, struct bin_attribute *attr,
+                             struct vm_area_struct *vma, int sparse)
+{
+        struct pci_dev *pdev = to_pci_dev(container_of(kobj,
+                                                       struct device, kobj));
+        struct resource *res = (struct resource *)attr->private;
+        enum pci_mmap_state mmap_type;
+        struct pci_bus_region bar;
+        int i;
+
+        for (i = 0; i < PCI_ROM_RESOURCE; i++)
+                if (res == &pdev->resource[i])
+                        break;
+        if (i >= PCI_ROM_RESOURCE)
+                return -ENODEV;
+
+        if (!__pci_mmap_fits(pdev, i, vma, sparse))
+                return -EINVAL;
+
+        if (iomem_is_exclusive(res->start))
+                return -EINVAL;
+
+        pcibios_resource_to_bus(pdev, &bar, res);
+        vma->vm_pgoff += bar.start >> (PAGE_SHIFT - (sparse ? 5 : 0));
+        mmap_type = res->flags & IORESOURCE_MEM ? pci_mmap_mem : pci_mmap_io;
+
+        return hose_mmap_page_range(pdev->sysdata, vma, mmap_type, sparse);
+}
+
+static int pci_mmap_resource_sparse(struct kobject *kobj,
+                                    struct bin_attribute *attr,
+                                    struct vm_area_struct *vma)
+{
+        return pci_mmap_resource(kobj, attr, vma, 1);
+}
+
+static int pci_mmap_resource_dense(struct kobject *kobj,
+                                   struct bin_attribute *attr,
+                                   struct vm_area_struct *vma)
+{
+        return pci_mmap_resource(kobj, attr, vma, 0);
+}
+
+/**
+ * pci_remove_resource_files - cleanup resource files
+ * @dev: dev to cleanup
+ *
+ * If we created resource files for @dev, remove them from sysfs and
+ * free their resources.
+ */
+void pci_remove_resource_files(struct pci_dev *pdev)
+{
+        int i;
+
+        for (i = 0; i < PCI_ROM_RESOURCE; i++) {
+                struct bin_attribute *res_attr;
+
+                res_attr = pdev->res_attr[i];
+                if (res_attr) {
+                        sysfs_remove_bin_file(&pdev->dev.kobj, res_attr);
+                        kfree(res_attr);
+                }
+
+                res_attr = pdev->res_attr_wc[i];
+                if (res_attr) {
+                        sysfs_remove_bin_file(&pdev->dev.kobj, res_attr);
+                        kfree(res_attr);
+                }
+        }
+}
+
+static int sparse_mem_mmap_fits(struct pci_dev *pdev, int num)
+{
+        struct pci_bus_region bar;
+        struct pci_controller *hose = pdev->sysdata;
+        long dense_offset;
+        unsigned long sparse_size;
+
+        pcibios_resource_to_bus(pdev, &bar, &pdev->resource[num]);
+
+        /* All core logic chips have 4G sparse address space, except
+           CIA which has 16G (see xxx_SPARSE_MEM and xxx_DENSE_MEM
+           definitions in asm/core_xxx.h files). This corresponds
+           to 128M or 512M of the bus space. */
+        dense_offset = (long)(hose->dense_mem_base - hose->sparse_mem_base);
+        sparse_size = dense_offset >= 0x400000000UL ? 0x20000000 : 0x8000000;
+
+        return bar.end < sparse_size;
+}
+
+static int pci_create_one_attr(struct pci_dev *pdev, int num, char *name,
+                               char *suffix, struct bin_attribute *res_attr,
+                               unsigned long sparse)
+{
+        size_t size = pci_resource_len(pdev, num);
+
+        sprintf(name, "resource%d%s", num, suffix);
+        res_attr->mmap = sparse ? pci_mmap_resource_sparse :
+                                  pci_mmap_resource_dense;
+        res_attr->attr.name = name;
+        res_attr->attr.mode = S_IRUSR | S_IWUSR;
+        res_attr->size = sparse ? size << 5 : size;
+        res_attr->private = &pdev->resource[num];
+        return sysfs_create_bin_file(&pdev->dev.kobj, res_attr);
+}
+
+static int pci_create_attr(struct pci_dev *pdev, int num)
+{
+        /* allocate attribute structure, piggyback attribute name */
+        int retval, nlen1, nlen2 = 0, res_count = 1;
+        unsigned long sparse_base, dense_base;
+        struct bin_attribute *attr;
+        struct pci_controller *hose = pdev->sysdata;
+        char *suffix, *attr_name;
+
+        suffix = "";    /* Assume bwx machine, normal resourceN files. */
+        nlen1 = 10;
+
+        if (pdev->resource[num].flags & IORESOURCE_MEM) {
+                sparse_base = hose->sparse_mem_base;
+                dense_base = hose->dense_mem_base;
+                if (sparse_base && !sparse_mem_mmap_fits(pdev, num)) {
+                        sparse_base = 0;
+                        suffix = "_dense";
+                        nlen1 = 16;     /* resourceN_dense */
+                }
+        } else {
+                sparse_base = hose->sparse_io_base;
+                dense_base = hose->dense_io_base;
+        }
+
+        if (sparse_base) {
+                suffix = "_sparse";
+                nlen1 = 17;
+                if (dense_base) {
+                        nlen2 = 16;     /* resourceN_dense */
+                        res_count = 2;
+                }
+        }
+
+        attr = kzalloc(sizeof(*attr) * res_count + nlen1 + nlen2, GFP_ATOMIC);
+        if (!attr)
+                return -ENOMEM;
+
+        /* Create bwx, sparse or single dense file */
+        attr_name = (char *)(attr + res_count);
+        pdev->res_attr[num] = attr;
+        retval = pci_create_one_attr(pdev, num, attr_name, suffix, attr,
+                                     sparse_base);
+        if (retval || res_count == 1)
+                return retval;
+
+        /* Create dense file */
+        attr_name += nlen1;
+        attr++;
+        pdev->res_attr_wc[num] = attr;
+        return pci_create_one_attr(pdev, num, attr_name, "_dense", attr, 0);
+}
+
+/**
+ * pci_create_resource_files - create resource files in sysfs for @dev
+ * @dev: dev in question
+ *
+ * Walk the resources in @dev creating files for each resource available.
+ */
+int pci_create_resource_files(struct pci_dev *pdev)
+{
+        int i;
+        int retval;
+
+        /* Expose the PCI resources from this device as files */
+        for (i = 0; i < PCI_ROM_RESOURCE; i++) {
+
+                /* skip empty resources */
+                if (!pci_resource_len(pdev, i))
+                        continue;
+
+                retval = pci_create_attr(pdev, i);
+                if (retval) {
+                        pci_remove_resource_files(pdev);
+                        return retval;
+                }
+        }
+        return 0;
+}
+
+/* Legacy I/O bus mapping stuff. */
+
+static int __legacy_mmap_fits(struct pci_controller *hose,
+                              struct vm_area_struct *vma,
+                              unsigned long res_size, int sparse)
+{
+        unsigned long nr, start, size;
+
+        nr = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
+        start = vma->vm_pgoff;
+        size = ((res_size - 1) >> PAGE_SHIFT) + 1;
+
+        if (start < size && size - start >= nr)
+                return 1;
+        WARN(1, "process \"%s\" tried to map%s 0x%08lx-0x%08lx on hose %d "
+                "(size 0x%08lx)\n",
+                current->comm, sparse ? " sparse" : "", start, start + nr,
+                hose->index, size);
+        return 0;
+}
+
+static inline int has_sparse(struct pci_controller *hose,
+                             enum pci_mmap_state mmap_type)
+{
+        unsigned long base;
+
+        base = (mmap_type == pci_mmap_mem) ? hose->sparse_mem_base :
+                                             hose->sparse_io_base;
+
+        return base != 0;
+}
+
+int pci_mmap_legacy_page_range(struct pci_bus *bus, struct vm_area_struct *vma,
+                               enum pci_mmap_state mmap_type)
+{
+        struct pci_controller *hose = bus->sysdata;
+        int sparse = has_sparse(hose, mmap_type);
+        unsigned long res_size;
+
+        res_size = (mmap_type == pci_mmap_mem) ? bus->legacy_mem->size :
+                                                 bus->legacy_io->size;
+        if (!__legacy_mmap_fits(hose, vma, res_size, sparse))
+                return -EINVAL;
+
+        return hose_mmap_page_range(hose, vma, mmap_type, sparse);
+}
+
+/**
+ * pci_adjust_legacy_attr - adjustment of legacy file attributes
+ * @b: bus to create files under
+ * @mmap_type: I/O port or memory
+ *
+ * Adjust file name and size for sparse mappings.
+ */
+void pci_adjust_legacy_attr(struct pci_bus *bus, enum pci_mmap_state mmap_type)
+{
+        struct pci_controller *hose = bus->sysdata;
+
+        if (!has_sparse(hose, mmap_type))
+                return;
+
+        if (mmap_type == pci_mmap_mem) {
+                bus->legacy_mem->attr.name = "legacy_mem_sparse";
+                bus->legacy_mem->size <<= 5;
+        } else {
+                bus->legacy_io->attr.name = "legacy_io_sparse";
+                bus->legacy_io->size <<= 5;
+        }
+        return;
+}
+
+/* Legacy I/O bus read/write functions */
+int pci_legacy_read(struct pci_bus *bus, loff_t port, u32 *val, size_t size)
+{
+        struct pci_controller *hose = bus->sysdata;
+
+        port += hose->io_space->start;
+
+        switch(size) {
+        case 1:
+                *((u8 *)val) = inb(port);
+                return 1;
+        case 2:
+                if (port & 1)
+                        return -EINVAL;
+                *((u16 *)val) = inw(port);
+                return 2;
+        case 4:
+                if (port & 3)
+                        return -EINVAL;
+                *((u32 *)val) = inl(port);
+                return 4;
+        }
+        return -EINVAL;
+}
+
+int pci_legacy_write(struct pci_bus *bus, loff_t port, u32 val, size_t size)
+{
+        struct pci_controller *hose = bus->sysdata;
+
+        port += hose->io_space->start;
+
+        switch(size) {
+        case 1:
+                outb(port, val);
+                return 1;
+        case 2:
+                if (port & 1)
+                        return -EINVAL;
+                outw(port, val);
+                return 2;
+        case 4:
+                if (port & 3)
+                        return -EINVAL;
+                outl(port, val);
+                return 4;
+        }
+        return -EINVAL;
+}