From bhutchings@solarflare.com Wed Mar 12 14:46:31 2008 From: Ben Hutchings Date: Wed, 5 Mar 2008 16:52:39 +0000 Subject: PCI: Expose PCI VPD through sysfs To: linux-pci@atrey.karlin.mff.cuni.cz Cc: Greg KH Message-ID: <20080305165238.GS2988@solarflare.com> Content-Disposition: inline From: Ben Hutchings Vital Product Data (VPD) may be exposed by PCI devices in several ways. It is generally unsafe to read this information through the existing interfaces to user-land because of stateful interfaces. This adds: - abstract operations for VPD access (struct pci_vpd_ops) - VPD state information in struct pci_dev (struct pci_vpd) - an implementation of the VPD access method specified in PCI 2.2 (in access.c) - a 'vpd' binary file in sysfs directories for PCI devices with VPD operations defined It adds a probe for PCI 2.2 VPD in pci_scan_device() and release of VPD state in pci_release_dev(). Signed-off-by: Ben Hutchings Signed-off-by: Greg Kroah-Hartman --- Documentation/ABI/testing/sysfs-bus-pci | 11 ++ drivers/pci/access.c | 166 ++++++++++++++++++++++++++++++++ drivers/pci/pci-sysfs.c | 109 ++++++++++++++++++--- drivers/pci/pci.h | 19 +++ drivers/pci/probe.c | 3 include/linux/pci.h | 3 6 files changed, 297 insertions(+), 14 deletions(-) --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -0,0 +1,11 @@ +What: /sys/bus/pci/devices/.../vpd +Date: February 2008 +Contact: Ben Hutchings +Description: + A file named vpd in a device directory will be a + binary file containing the Vital Product Data for the + device. It should follow the VPD format defined in + PCI Specification 2.1 or 2.2, but users should consider + that some devices may have malformatted data. If the + underlying VPD has a writable section then the + corresponding section of this file will be writable. --- a/drivers/pci/access.c +++ b/drivers/pci/access.c @@ -1,3 +1,4 @@ +#include #include #include #include @@ -126,6 +127,171 @@ PCI_USER_WRITE_CONFIG(byte, u8) PCI_USER_WRITE_CONFIG(word, u16) PCI_USER_WRITE_CONFIG(dword, u32) +/* VPD access through PCI 2.2+ VPD capability */ + +#define PCI_VPD_PCI22_SIZE (PCI_VPD_ADDR_MASK + 1) + +struct pci_vpd_pci22 { + struct pci_vpd base; + spinlock_t lock; /* controls access to hardware and the flags */ + u8 cap; + bool busy; + bool flag; /* value of F bit to wait for */ +}; + +/* Wait for last operation to complete */ +static int pci_vpd_pci22_wait(struct pci_dev *dev) +{ + struct pci_vpd_pci22 *vpd = + container_of(dev->vpd, struct pci_vpd_pci22, base); + u16 flag, status; + int wait; + int ret; + + if (!vpd->busy) + return 0; + + flag = vpd->flag ? PCI_VPD_ADDR_F : 0; + wait = vpd->flag ? 10 : 1000; /* read: 100 us; write: 10 ms */ + for (;;) { + ret = pci_user_read_config_word(dev, + vpd->cap + PCI_VPD_ADDR, + &status); + if (ret < 0) + return ret; + if ((status & PCI_VPD_ADDR_F) == flag) { + vpd->busy = false; + return 0; + } + if (wait-- == 0) + return -ETIMEDOUT; + udelay(10); + } +} + +static int pci_vpd_pci22_read(struct pci_dev *dev, int pos, int size, + char *buf) +{ + struct pci_vpd_pci22 *vpd = + container_of(dev->vpd, struct pci_vpd_pci22, base); + u32 val; + int ret; + int begin, end, i; + + if (pos < 0 || pos > PCI_VPD_PCI22_SIZE || + size > PCI_VPD_PCI22_SIZE - pos) + return -EINVAL; + if (size == 0) + return 0; + + spin_lock_irq(&vpd->lock); + ret = pci_vpd_pci22_wait(dev); + if (ret < 0) + goto out; + ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR, + pos & ~3); + if (ret < 0) + goto out; + vpd->busy = true; + vpd->flag = 1; + ret = pci_vpd_pci22_wait(dev); + if (ret < 0) + goto out; + ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, + &val); +out: + spin_unlock_irq(&vpd->lock); + if (ret < 0) + return ret; + + /* Convert to bytes */ + begin = pos & 3; + end = min(4, begin + size); + for (i = 0; i < end; ++i) { + if (i >= begin) + *buf++ = val; + val >>= 8; + } + return end - begin; +} + +static int pci_vpd_pci22_write(struct pci_dev *dev, int pos, int size, + const char *buf) +{ + struct pci_vpd_pci22 *vpd = + container_of(dev->vpd, struct pci_vpd_pci22, base); + u32 val; + int ret; + + if (pos < 0 || pos > PCI_VPD_PCI22_SIZE || pos & 3 || + size > PCI_VPD_PCI22_SIZE - pos || size < 4) + return -EINVAL; + + val = (u8) *buf++; + val |= ((u8) *buf++) << 8; + val |= ((u8) *buf++) << 16; + val |= ((u32)(u8) *buf++) << 24; + + spin_lock_irq(&vpd->lock); + ret = pci_vpd_pci22_wait(dev); + if (ret < 0) + goto out; + ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA, + val); + if (ret < 0) + goto out; + ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR, + pos | PCI_VPD_ADDR_F); + if (ret < 0) + goto out; + vpd->busy = true; + vpd->flag = 0; + ret = pci_vpd_pci22_wait(dev); +out: + spin_unlock_irq(&vpd->lock); + if (ret < 0) + return ret; + + return 4; +} + +static int pci_vpd_pci22_get_size(struct pci_dev *dev) +{ + return PCI_VPD_PCI22_SIZE; +} + +static void pci_vpd_pci22_release(struct pci_dev *dev) +{ + kfree(container_of(dev->vpd, struct pci_vpd_pci22, base)); +} + +static struct pci_vpd_ops pci_vpd_pci22_ops = { + .read = pci_vpd_pci22_read, + .write = pci_vpd_pci22_write, + .get_size = pci_vpd_pci22_get_size, + .release = pci_vpd_pci22_release, +}; + +int pci_vpd_pci22_init(struct pci_dev *dev) +{ + struct pci_vpd_pci22 *vpd; + u8 cap; + + cap = pci_find_capability(dev, PCI_CAP_ID_VPD); + if (!cap) + return -ENODEV; + vpd = kzalloc(sizeof(*vpd), GFP_ATOMIC); + if (!vpd) + return -ENOMEM; + + vpd->base.ops = &pci_vpd_pci22_ops; + spin_lock_init(&vpd->lock); + vpd->cap = cap; + vpd->busy = false; + dev->vpd = &vpd->base; + return 0; +} + /** * pci_block_user_cfg_access - Block userspace PCI config reads/writes * @dev: pci device struct --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -343,6 +343,58 @@ pci_write_config(struct kobject *kobj, s return count; } +static ssize_t +pci_read_vpd(struct kobject *kobj, struct bin_attribute *bin_attr, + char *buf, loff_t off, size_t count) +{ + struct pci_dev *dev = + to_pci_dev(container_of(kobj, struct device, kobj)); + int end; + int ret; + + if (off > bin_attr->size) + count = 0; + else if (count > bin_attr->size - off) + count = bin_attr->size - off; + end = off + count; + + while (off < end) { + ret = dev->vpd->ops->read(dev, off, end - off, buf); + if (ret < 0) + return ret; + buf += ret; + off += ret; + } + + return count; +} + +static ssize_t +pci_write_vpd(struct kobject *kobj, struct bin_attribute *bin_attr, + char *buf, loff_t off, size_t count) +{ + struct pci_dev *dev = + to_pci_dev(container_of(kobj, struct device, kobj)); + int end; + int ret; + + if (off > bin_attr->size) + count = 0; + else if (count > bin_attr->size - off) + count = bin_attr->size - off; + end = off + count; + + while (off < end) { + ret = dev->vpd->ops->write(dev, off, end - off, buf); + if (ret < 0) + return ret; + buf += ret; + off += ret; + } + + return count; +} + #ifdef HAVE_PCI_LEGACY /** * pci_read_legacy_io - read byte(s) from legacy I/O port space @@ -611,7 +663,7 @@ int __attribute__ ((weak)) pcibios_add_p int __must_check pci_create_sysfs_dev_files (struct pci_dev *pdev) { - struct bin_attribute *rom_attr = NULL; + struct bin_attribute *attr = NULL; int retval; if (!sysfs_initialized) @@ -624,22 +676,41 @@ int __must_check pci_create_sysfs_dev_fi if (retval) goto err; + /* If the device has VPD, try to expose it in sysfs. */ + if (pdev->vpd) { + attr = kzalloc(sizeof(*attr), GFP_ATOMIC); + if (attr) { + pdev->vpd->attr = attr; + attr->size = pdev->vpd->ops->get_size(pdev); + attr->attr.name = "vpd"; + attr->attr.mode = S_IRUGO | S_IWUSR; + attr->read = pci_read_vpd; + attr->write = pci_write_vpd; + retval = sysfs_create_bin_file(&pdev->dev.kobj, attr); + if (retval) + goto err_vpd; + } else { + retval = -ENOMEM; + goto err_config_file; + } + } + retval = pci_create_resource_files(pdev); if (retval) - goto err_bin_file; + goto err_vpd_file; /* If the device has a ROM, try to expose it in sysfs. */ if (pci_resource_len(pdev, PCI_ROM_RESOURCE) || (pdev->resource[PCI_ROM_RESOURCE].flags & IORESOURCE_ROM_SHADOW)) { - rom_attr = kzalloc(sizeof(*rom_attr), GFP_ATOMIC); - if (rom_attr) { - pdev->rom_attr = rom_attr; - rom_attr->size = pci_resource_len(pdev, PCI_ROM_RESOURCE); - rom_attr->attr.name = "rom"; - rom_attr->attr.mode = S_IRUSR; - rom_attr->read = pci_read_rom; - rom_attr->write = pci_write_rom; - retval = sysfs_create_bin_file(&pdev->dev.kobj, rom_attr); + attr = kzalloc(sizeof(*attr), GFP_ATOMIC); + if (attr) { + pdev->rom_attr = attr; + attr->size = pci_resource_len(pdev, PCI_ROM_RESOURCE); + attr->attr.name = "rom"; + attr->attr.mode = S_IRUSR; + attr->read = pci_read_rom; + attr->write = pci_write_rom; + retval = sysfs_create_bin_file(&pdev->dev.kobj, attr); if (retval) goto err_rom; } else { @@ -657,12 +728,18 @@ int __must_check pci_create_sysfs_dev_fi err_rom_file: if (pci_resource_len(pdev, PCI_ROM_RESOURCE)) - sysfs_remove_bin_file(&pdev->dev.kobj, rom_attr); + sysfs_remove_bin_file(&pdev->dev.kobj, pdev->rom_attr); err_rom: - kfree(rom_attr); + kfree(pdev->rom_attr); err_resource_files: pci_remove_resource_files(pdev); -err_bin_file: +err_vpd_file: + if (pdev->vpd) { + sysfs_remove_bin_file(&pdev->dev.kobj, pdev->vpd->attr); +err_vpd: + kfree(pdev->vpd->attr); + } +err_config_file: if (pdev->cfg_size < 4096) sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr); else @@ -684,6 +761,10 @@ void pci_remove_sysfs_dev_files(struct p pcie_aspm_remove_sysfs_dev_files(pdev); + if (pdev->vpd) { + sysfs_remove_bin_file(&pdev->dev.kobj, pdev->vpd->attr); + kfree(pdev->vpd->attr); + } if (pdev->cfg_size < 4096) sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr); else --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -18,6 +18,25 @@ extern int pci_user_write_config_byte(st extern int pci_user_write_config_word(struct pci_dev *dev, int where, u16 val); extern int pci_user_write_config_dword(struct pci_dev *dev, int where, u32 val); +struct pci_vpd_ops { + int (*read)(struct pci_dev *dev, int pos, int size, char *buf); + int (*write)(struct pci_dev *dev, int pos, int size, const char *buf); + int (*get_size)(struct pci_dev *dev); + void (*release)(struct pci_dev *dev); +}; + +struct pci_vpd { + struct pci_vpd_ops *ops; + struct bin_attribute *attr; /* descriptor for sysfs VPD entry */ +}; + +extern int pci_vpd_pci22_init(struct pci_dev *dev); +static inline void pci_vpd_release(struct pci_dev *dev) +{ + if (dev->vpd) + dev->vpd->ops->release(dev); +} + /* PCI /proc functions */ #ifdef CONFIG_PROC_FS extern int pci_proc_attach_device(struct pci_dev *dev); --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -794,6 +794,7 @@ static void pci_release_dev(struct devic struct pci_dev *pci_dev; pci_dev = to_pci_dev(dev); + pci_vpd_release(pci_dev); kfree(pci_dev); } @@ -933,6 +934,8 @@ pci_scan_device(struct pci_bus *bus, int return NULL; } + pci_vpd_pci22_init(dev); + return dev; } --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -20,6 +20,8 @@ /* Include the pci register defines */ #include +struct pci_vpd; + /* * The PCI interface treats multi-function devices as independent * devices. The slot/function address of each device is encoded @@ -206,6 +208,7 @@ struct pci_dev { #ifdef CONFIG_PCI_MSI struct list_head msi_list; #endif + struct pci_vpd *vpd; }; extern struct pci_dev *alloc_pci_dev(void);