Re: [PATCH] add PCI ROMs to sysfs

[Jon Smirl]

I can put together a new patch later tonight that reverts to the old
size scheme. It was more complicated since you need to allocate each
attribute.

I'll attach a newer version that incorporates a little feedback about
creating a function to remove the attribute for devices that don't want
to expose the ROM.

Alan Cox had concerns about copying the ROMs for those devices that
don't implement full address decoding. I'm using kmalloc for 40-60KB.
Would vmalloc be a better choice? Very few drivers will use the copy
option, mostly old hardware.

BenH said he would check it out on ppc but I haven't heard from him
yet.

Jesse, did you notice that the quirk for tracking the boot video device
is x86 only? I believe this needs to run on ia64 and x86_64 too. How do
we want to do that? It will do the wrong thing on architectures that
don't shadow video ROMs to C0000.

 
--- Greg KH <greg@xxxxxxxxx> wrote:

> On Wed, Aug 11, 2004 at 10:04:02AM -0700, Jesse Barnes wrote:
> > On Friday, August 6, 2004 2:14 pm, Jon Smirl wrote:
> > > Please check the code out and give it some testing. It will
> probably
> > > needs some adjustment for other platforms.
> > 
> > Jon, this works on my machine too.  Greg, if it looks ok can you
> pull it in?  
> > And can you add:
> > 
> >  * (C) Copyright 2004 Silicon Graphics, Inc.
> >  *       Jesse Barnes <jbarnes@xxxxxxx>
> > 
> > to pci-sysfs.c if you do?

I'll add this

> Care to send me a new patch?  Oh, and that copyright line needs to
> look
> like:
> * Copyright (c) 2004 Silicon Graphics, Inc. Jesse Barnes
> <jbarnes@xxxxxxx>
> 
> to make it legal, or so my lawyers say :)
> 
> > Greg was a little worried that your comment
> > 	/* .size is set individually for each device, sysfs copies it into
> dentry */
> > might not be correct.
> 
> I looked at the code, and he's right.  But it's pretty scary that it
> works correctly so I'd prefer to do it the way your patch did it
> (create
> a new attribute for every entry.)

I can revert back to the old code. The new scheme was just so much
simpler.

> 
> thanks,
> 
> greg k-h
> 

=====
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	Sat Aug  7 13:37:14 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 +165,193 @@
 	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);
+}
+
+static struct bin_attribute rom_attr;
+
+/**
+ * pci_remove_rom - disable the ROM and remove it's sysfs attribute
+ * @dev: pointer to pci device struct
+ *
+ */
+void 
+pci_remove_rom(struct pci_dev *dev) {
+	struct resource *res = &dev->resource[PCI_ROM_RESOURCE];
+	
+	if (pci_resource_len(dev, PCI_ROM_RESOURCE))
+		sysfs_remove_bin_file(&dev->dev.kobj, &rom_attr);
+	if (!(res->flags & (PCI_ROM_ADDRESS_ENABLE | PCI_ROM_SHADOW | PCI_ROM_COPY)))
+		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 +374,53 @@
 	.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	Sat Aug  7 13:33:34 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 +779,12 @@
 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);
+
+/* ROM control related routines */
+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);
+void pci_remove_rom(struct pci_dev *dev);
 
 /* Power management related routines */
 int pci_save_state(struct pci_dev *dev, u32 *buffer);