Re: [PATCH] add PCI ROMs to sysfs
From: Jon Smirl
Date: Fri Aug 06 2004 - 16:23:11 EST
Version 11
I removed the call to pci_alloc_resource(). The sysfs attribute code
builds the attributes before the pci subsystem is fully initialized.
Specifically before arch pcibios_init() has been called. If
pci_alloc_resource() is called for the ROM before pcibios_init() the
kernel's resource maps have not been built yet. This will result in the
ROM being located on top of the framebuffer; as soon as it is enabled
the system will lock. Right now the code relies on the BIOS getting
things set up right. If we can figure out how to initialize the sysfs
attributes after pcibios_init() then I can put the alloc call back.
Changes the API to make it useful from a device driver:
pci_map_rom - map the rom and provide virtual address, transparently
return shadow/copy if needed. Normal drivers call this
pci_map_rom_copy - same as pci_map_rom except the ROM will copied,
future reads of ROM will use copy. Hardware with minimal decoding calls
this
pci_unmap_rom - release the ioremap if there is one
If the ROM code finds the 55 AA signature at the start of the ROM it
will use the len/512 from the third byte for the length. The PCI window
is often much larger than the ROM really is so this saves a lot of
memory for copied ROMs.
I added two new defines in pci.h
#define PCI_ROM_SHADOW 0x02 /* resource flag, ROM is copy at C000:0 */
#define PCI_ROM_COPY 0x04 /* resource flag, ROM is alloc'd copy */
I don't think these conflict with anything, please check to make sure.
Please check the code out and give it some testing. It will probably
needs some adjustment for other platforms.
=====
Jon Smirl
jonsmirl@xxxxxxxxx
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http://promotions.yahoo.com/new_mail ===== arch/i386/pci/fixup.c 1.19 vs edited =====
--- 1.19/arch/i386/pci/fixup.c Thu Jun 3 10:58:17 2004
+++ edited/arch/i386/pci/fixup.c Thu Aug 5 00:20:08 2004
@@ -237,6 +237,29 @@
}
}
+static void __devinit pci_fixup_video(struct pci_dev *pdev)
+{
+ struct pci_dev *bridge;
+ struct pci_bus *bus;
+ u16 l;
+
+ if ((pdev->class >> 8) != PCI_CLASS_DISPLAY_VGA)
+ return;
+
+ /* Is VGA routed to us? */
+ bus = pdev->bus;
+ while (bus) {
+ bridge = bus->self;
+ if (bridge) {
+ pci_read_config_word(bridge, PCI_BRIDGE_CONTROL, &l);
+ if (!(l & PCI_BRIDGE_CTL_VGA))
+ return;
+ }
+ bus = bus->parent;
+ }
+ pdev->resource[PCI_ROM_RESOURCE].flags |= PCI_ROM_SHADOW;
+}
+
struct pci_fixup pcibios_fixups[] = {
{
.pass = PCI_FIXUP_HEADER,
@@ -345,6 +368,12 @@
.vendor = PCI_VENDOR_ID_NVIDIA,
.device = PCI_DEVICE_ID_NVIDIA_NFORCE2,
.hook = pci_fixup_nforce2
+ },
+ {
+ .pass = PCI_FIXUP_FINAL,
+ .vendor = PCI_ANY_ID,
+ .device = PCI_ANY_ID,
+ .hook = pci_fixup_video
},
{ .pass = 0 }
};
===== drivers/pci/pci-sysfs.c 1.10 vs edited =====
--- 1.10/drivers/pci/pci-sysfs.c Fri Jun 4 09:23:04 2004
+++ edited/drivers/pci/pci-sysfs.c Fri Aug 6 16:38:00 2004
@@ -5,6 +5,7 @@
* (C) Copyright 2002-2004 IBM Corp.
* (C) Copyright 2003 Matthew Wilcox
* (C) Copyright 2003 Hewlett-Packard
+ * (C) Copyright 2004 Jon Smirl
*
* File attributes for PCI devices
*
@@ -164,6 +165,176 @@
return count;
}
+/**
+ * pci_enable_rom - enable ROM decoding for a PCI device
+ * @dev: PCI device to enable
+ *
+ * Enable ROM decoding on @dev. This involves simply turning on the last
+ * bit of the PCI ROM BAR. Note that some cards may share address decoders
+ * between the ROM and other resources, so enabling it may disable access
+ * to MMIO registers or other card memory.
+ */
+static void
+pci_enable_rom(struct pci_dev *dev)
+{
+ u32 rom_addr;
+
+ pci_read_config_dword(dev, dev->rom_base_reg, &rom_addr);
+ rom_addr |= PCI_ROM_ADDRESS_ENABLE;
+ pci_write_config_dword(dev, dev->rom_base_reg, rom_addr);
+}
+
+/**
+ * pci_disable_rom - disable ROM decoding for a PCI device
+ * @dev: PCI device to disable
+ *
+ * Disable ROM decoding on a PCI device by turning off the last bit in the
+ * ROM BAR.
+ */
+static void
+pci_disable_rom(struct pci_dev *dev)
+{
+ u32 rom_addr;
+ pci_read_config_dword(dev, dev->rom_base_reg, &rom_addr);
+ rom_addr &= ~PCI_ROM_ADDRESS_ENABLE;
+ pci_write_config_dword(dev, dev->rom_base_reg, rom_addr);
+}
+
+/**
+ * pci_map_rom - map a PCI ROM to kernel space
+ * @dev: pointer to pci device struct
+ * @size: pointer to receive size of pci window over ROM
+ * @return: kernel virtual pointer to image of ROM
+ *
+ * Map a PCI ROM into kernel space. If ROM is boot video ROM,
+ * the shadow BIOS copy will be returned instead of the
+ * actual ROM.
+ */
+unsigned char *
+pci_map_rom(struct pci_dev *dev, size_t *size) {
+ struct resource *res = &dev->resource[PCI_ROM_RESOURCE];
+ loff_t start;
+ unsigned char *rom;
+
+ if (res->flags & PCI_ROM_SHADOW) { /* PCI_ROM_SHADOW only set on x86 */
+ start = (loff_t)0xC0000; /* primary video rom always starts here */
+ *size = 0x20000; /* cover C000:0 through E000:0 */
+ } else if (res->flags & PCI_ROM_COPY) {
+ *size = pci_resource_len(dev, PCI_ROM_RESOURCE);
+ return (unsigned char *)pci_resource_start(dev, PCI_ROM_RESOURCE);
+ } else {
+ start = pci_resource_start(dev, PCI_ROM_RESOURCE);
+ *size = pci_resource_len(dev, PCI_ROM_RESOURCE);
+ if (*size == 0)
+ return NULL;
+
+ /* Enable ROM space decodes */
+ pci_enable_rom(dev);
+ }
+
+ rom = ioremap(start, *size);
+ if (!rom) {
+ /* restore enable if ioremap fails */
+ if (!(res->flags & (PCI_ROM_ADDRESS_ENABLE | PCI_ROM_SHADOW | PCI_ROM_COPY)))
+ pci_disable_rom(dev);
+ return NULL;
+ }
+ /* Standard PCI ROMs start out with these three bytes 55 AA size/512 */
+ if ((*rom == 0x55) && (*(rom + 1) == 0xAA))
+ *size = *(rom + 2) * 512; /* return true ROM size, not PCI window size */
+
+ return rom;
+}
+
+/**
+ * pci_map_rom_copy - map a PCI ROM to kernel space, create a copy
+ * @dev: pointer to pci device struct
+ * @size: pointer to receive size of pci window over ROM
+ * @return: kernel virtual pointer to image of ROM
+ *
+ * Map a PCI ROM into kernel space. If ROM is boot video ROM,
+ * the shadow BIOS copy will be returned instead of the
+ * actual ROM.
+ */
+unsigned char *
+pci_map_rom_copy(struct pci_dev *dev, size_t *size) {
+ struct resource *res = &dev->resource[PCI_ROM_RESOURCE];
+ unsigned char *rom;
+
+ rom = pci_map_rom(dev, size);
+ if (!rom)
+ return NULL;
+
+ if (res->flags & (PCI_ROM_COPY | PCI_ROM_SHADOW))
+ return rom;
+
+ res->start = (unsigned long)kmalloc(*size, GFP_KERNEL);
+ if (!res->start)
+ return rom;
+
+ res->end = res->start + *size;
+ memcpy((void*)res->start, rom, *size);
+ pci_unmap_rom(dev, rom);
+ res->flags |= PCI_ROM_COPY;
+
+ return (unsigned char *)res->start;
+}
+
+/**
+ * pci_unmap_rom - unmap the ROM from kernel space
+ * @dev: pointer to pci device struct
+ * @rom: virtual address of the previous mapping
+ *
+ * Remove a mapping of a previously mapped ROM
+ */
+void
+pci_unmap_rom(struct pci_dev *dev, unsigned char *rom) {
+ struct resource *res = &dev->resource[PCI_ROM_RESOURCE];
+
+ if (res->flags & PCI_ROM_COPY)
+ return;
+
+ iounmap(rom);
+
+ /* Disable again before continuing, leave enabled if pci=rom */
+ if (!(res->flags & (PCI_ROM_ADDRESS_ENABLE | PCI_ROM_SHADOW)))
+ pci_disable_rom(dev);
+}
+
+/**
+ * pci_read_rom - read a PCI ROM
+ * @kobj: kernel object handle
+ * @buf: where to put the data we read from the ROM
+ * @off: file offset
+ * @count: number of bytes to read
+ *
+ * Put @count bytes starting at @off into @buf from the ROM in the PCI
+ * device corresponding to @kobj.
+ */
+static ssize_t
+pci_read_rom(struct kobject *kobj, char *buf, loff_t off, size_t count)
+{
+ struct pci_dev *dev = to_pci_dev(container_of(kobj,struct device,kobj));
+ unsigned char *rom;
+ size_t size;
+
+ rom = pci_map_rom(dev, &size); /* size starts out as PCI window size */
+ if (!rom)
+ return 0;
+
+ if (off >= size)
+ count = 0;
+ else {
+ if (off + count > size)
+ count = size - off;
+
+ memcpy_fromio(buf, rom + off, count);
+ }
+ pci_unmap_rom(dev, rom);
+
+ return count;
+}
+
static struct bin_attribute pci_config_attr = {
.attr = {
.name = "config",
@@ -186,13 +357,53 @@
.write = pci_write_config,
};
-void pci_create_sysfs_dev_files (struct pci_dev *pdev)
+static struct bin_attribute rom_attr = {
+ .attr = {
+ .name = "rom",
+ .mode = S_IRUSR,
+ .owner = THIS_MODULE,
+ },
+ /* .size is set individually for each device, sysfs copies it into dentry */
+ .read = pci_read_rom,
+};
+
+void pci_create_sysfs_dev_files(struct pci_dev *pdev)
{
if (pdev->cfg_size < 4096)
sysfs_create_bin_file(&pdev->dev.kobj, &pci_config_attr);
else
sysfs_create_bin_file(&pdev->dev.kobj, &pcie_config_attr);
+ /* If the device has a ROM, try to expose it in sysfs. */
+ if (pci_resource_len(pdev, PCI_ROM_RESOURCE)) {
+ unsigned char *rom;
+ rom = pci_map_rom(pdev, &rom_attr.size);
+ if (rom) {
+ pci_unmap_rom(pdev, rom);
+ sysfs_create_bin_file(&pdev->dev.kobj, &rom_attr);
+ }
+ }
/* add platform-specific attributes */
pcibios_add_platform_entries(pdev);
}
+
+/**
+ * pci_remove_sysfs_dev_files - cleanup PCI specific sysfs files
+ * @pdev: device whose entries we should free
+ *
+ * Cleanup when @pdev is removed from sysfs.
+ */
+void pci_remove_sysfs_dev_files(struct pci_dev *pdev)
+{
+ if (pdev->cfg_size < 4096)
+ sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr);
+ else
+ sysfs_remove_bin_file(&pdev->dev.kobj, &pcie_config_attr);
+
+ if (pci_resource_len(pdev, PCI_ROM_RESOURCE))
+ sysfs_remove_bin_file(&pdev->dev.kobj, &rom_attr);
+}
+
+EXPORT_SYMBOL(pci_map_rom);
+EXPORT_SYMBOL(pci_map_rom_copy);
+EXPORT_SYMBOL(pci_unmap_rom);
===== drivers/pci/pci.h 1.12 vs edited =====
--- 1.12/drivers/pci/pci.h Fri Jun 4 09:23:04 2004
+++ edited/drivers/pci/pci.h Tue Aug 3 17:05:19 2004
@@ -3,6 +3,7 @@
extern int pci_hotplug (struct device *dev, char **envp, int num_envp,
char *buffer, int buffer_size);
extern void pci_create_sysfs_dev_files(struct pci_dev *pdev);
+extern void pci_remove_sysfs_dev_files(struct pci_dev *pdev);
extern int pci_bus_alloc_resource(struct pci_bus *bus, struct resource *res,
unsigned long size, unsigned long align,
unsigned long min, unsigned int type_mask,
===== drivers/pci/remove.c 1.3 vs edited =====
--- 1.3/drivers/pci/remove.c Tue Feb 3 12:17:30 2004
+++ edited/drivers/pci/remove.c Fri Aug 6 15:36:18 2004
@@ -12,12 +12,22 @@
static void pci_free_resources(struct pci_dev *dev)
{
+ struct resource *res;
int i;
msi_remove_pci_irq_vectors(dev);
+ if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL) {
+ res = &dev->resource[PCI_ROM_RESOURCE];
+ if (res->flags & PCI_ROM_COPY) {
+ kfree((void*)res->start);
+ res->flags &= !PCI_ROM_COPY;
+ res->start = 0;
+ res->end = 0;
+ }
+ }
for (i = 0; i < PCI_NUM_RESOURCES; i++) {
- struct resource *res = dev->resource + i;
+ res = dev->resource + i;
if (res->parent)
release_resource(res);
}
@@ -26,6 +36,7 @@
static void pci_destroy_dev(struct pci_dev *dev)
{
pci_proc_detach_device(dev);
+ pci_remove_sysfs_dev_files(dev);
device_unregister(&dev->dev);
/* Remove the device from the device lists, and prevent any further
===== include/linux/pci.h 1.132 vs edited =====
--- 1.132/include/linux/pci.h Mon Aug 2 04:00:43 2004
+++ edited/include/linux/pci.h Fri Aug 6 00:34:27 2004
@@ -102,6 +102,8 @@
#define PCI_SUBSYSTEM_ID 0x2e
#define PCI_ROM_ADDRESS 0x30 /* Bits 31..11 are address, 10..1 reserved */
#define PCI_ROM_ADDRESS_ENABLE 0x01
+#define PCI_ROM_SHADOW 0x02 /* resource flag, ROM is copy at C000:0 */
+#define PCI_ROM_COPY 0x04 /* resource flag, ROM is alloc'd copy */
#define PCI_ROM_ADDRESS_MASK (~0x7ffUL)
#define PCI_CAPABILITY_LIST 0x34 /* Offset of first capability list entry */
@@ -777,6 +779,9 @@
int pci_dac_set_dma_mask(struct pci_dev *dev, u64 mask);
int pci_set_consistent_dma_mask(struct pci_dev *dev, u64 mask);
int pci_assign_resource(struct pci_dev *dev, int i);
+unsigned char *pci_map_rom(struct pci_dev *dev, size_t *size);
+unsigned char *pci_map_rom_copy(struct pci_dev *dev, size_t *size);
+void pci_unmap_rom(struct pci_dev *dev, unsigned char *rom);
/* Power management related routines */
int pci_save_state(struct pci_dev *dev, u32 *buffer);