[PATCH] alpha: pci sysfs resources

From: Ivan Kokshaysky
Date: Tue Feb 17 2009 - 05:46:58 EST

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@xxxxxxxxxxxxxxxxxxxx>
---
arch/alpha/include/asm/pci.h | 14 ++
arch/alpha/kernel/Makefile | 2 +-
arch/alpha/kernel/pci-sysfs.c | 366 +++++++++++++++++++++++++++++++++++++++++
drivers/pci/pci-sysfs.c | 19 ++-
4 files changed, 398 insertions(+), 3 deletions(-)

diff --git a/arch/alpha/include/asm/pci.h b/arch/alpha/include/asm/pci.h
index 2a14302..cb04eaa 100644
--- a/arch/alpha/include/asm/pci.h
+++ b/arch/alpha/include/asm/pci.h
@@ -273,4 +273,18 @@ struct pci_dev *alpha_gendev_to_pci(struct device *dev);

extern struct pci_dev *isa_bridge;

+extern int pci_legacy_read(struct pci_bus *bus, loff_t port, u32 *val,
+ size_t count);
+extern int pci_legacy_write(struct pci_bus *bus, loff_t port, u32 val,
+ size_t count);
+extern int pci_mmap_legacy_page_range(struct pci_bus *bus,
+ struct vm_area_struct *vma,
+ enum pci_mmap_state mmap_state);
+extern void pci_adjust_legacy_attr(struct pci_bus *bus,
+ enum pci_mmap_state mmap_type);
+#define HAVE_PCI_LEGACY 1
+
+extern int pci_create_resource_files(struct pci_dev *dev);
+extern void pci_remove_resource_files(struct pci_dev *dev);
+
#endif /* __ALPHA_PCI_H */
diff --git a/arch/alpha/kernel/Makefile b/arch/alpha/kernel/Makefile
index e203713..7739a62 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 0000000..6ea822e
--- /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;
+}
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index dfc4e0d..1c89298 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -493,6 +493,19 @@ pci_mmap_legacy_io(struct kobject *kobj, struct bin_attribute *attr,
}

/**
+ * pci_adjust_legacy_attr - adjustment of legacy file attributes
+ * @b: bus to create files under
+ * @mmap_type: I/O port or memory
+ *
+ * Stub implementation. Can be overridden by arch if necessary.
+ */
+void __weak
+pci_adjust_legacy_attr(struct pci_bus *b, enum pci_mmap_state mmap_type)
+{
+ return;
+}
+
+/**
* pci_create_legacy_files - create legacy I/O port and memory files
* @b: bus to create files under
*
@@ -518,6 +531,7 @@ void pci_create_legacy_files(struct pci_bus *b)
b->legacy_io->read = pci_read_legacy_io;
b->legacy_io->write = pci_write_legacy_io;
b->legacy_io->mmap = pci_mmap_legacy_io;
+ pci_adjust_legacy_attr(b, pci_mmap_io);
error = device_create_bin_file(&b->dev, b->legacy_io);
if (error)
goto legacy_io_err;
@@ -528,6 +542,7 @@ void pci_create_legacy_files(struct pci_bus *b)
b->legacy_mem->size = 1024*1024;
b->legacy_mem->attr.mode = S_IRUSR | S_IWUSR;
b->legacy_mem->mmap = pci_mmap_legacy_mem;
+ pci_adjust_legacy_attr(b, pci_mmap_mem);
error = device_create_bin_file(&b->dev, b->legacy_mem);
if (error)
goto legacy_mem_err;
@@ -719,8 +734,8 @@ static int pci_create_resource_files(struct pci_dev *pdev)
return 0;
}
#else /* !HAVE_PCI_MMAP */
-static inline int pci_create_resource_files(struct pci_dev *dev) { return 0; }
-static inline void pci_remove_resource_files(struct pci_dev *dev) { return; }
+int __weak pci_create_resource_files(struct pci_dev *dev) { return 0; }
+void __weak pci_remove_resource_files(struct pci_dev *dev) { return; }
#endif /* HAVE_PCI_MMAP */

/**
--
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