| Message ID | 1412693312-2449-1-git-send-email-marcel.a@redhat.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Tue, Oct 07, 2014 at 05:48:32PM +0300, Marcel Apfelbaum wrote: > Scanning a lot of devices during boot requires a lot of time. > On other scenarios there is a need to bind a driver to a specific slot. > > Binding devices to pci-stub driver does not work, > as it will not differentiate between devices of the > same type. Using some start scripts is error prone. > > The solution leverages driver_override functionality introduced by > > commit: 782a985d7af26db39e86070d28f987cad21313c0 > Author: Alex Williamson <alex.williamson@redhat.com> > Date: Tue May 20 08:53:21 2014 -0600 > > PCI: Introduce new device binding path using pci_dev.driver_override > > In order to bind PCI slots to specific drivers use: > pci=driver[xxxx:xx:xx.x]=foo,driver[xxxx:xx:xx.x]=bar,... > > Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com> > --- > v2 -> v3: > - Corrected subject line > v1 -> v2: > - Addressed Michael S. Tsirkin comments > - Removed 32 slots limitation > - Better handling of memory allocation failures > (preferred BUG_ON over error messages) > - Addressed Alex Williamson's comments: > - Modified commit message to show parameter usage more clear. > - I preferred to re-use parse_args instead of manually using > strstr in order to better comply with command line parsing > rules. > - I didn't use any locking when parsing the command line args > (see parse_done usage) assuming that first call will be > early in system boot and no race can occur. Please correct > me if I am wrong. > > Notes: > - I have further ideas on top of this patch based on your reviews. > I thought of: > - Use wildcards to specify entire buses/devices, something like: > driver[0001:02:*.*]=pci-stub > - Use comma to separate several devices: > driver[0001:02:03.4,0001:02:04.0,...]=pci-stub > - Make domain optional: > driver[00:03.0]=pci-stub > > Comments will be appreciated, > Thanks, > Marcel > Documentation/kernel-parameters.txt | 4 ++ > drivers/pci/bus.c | 86 +++++++++++++++++++++++++++++++++++++ > drivers/pci/pci.c | 2 + > 3 files changed, 92 insertions(+) > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > index 5ae8608..c1cbb4c 100644 > --- a/Documentation/kernel-parameters.txt > +++ b/Documentation/kernel-parameters.txt > @@ -2631,6 +2631,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > pcie_scan_all Scan all possible PCIe devices. Otherwise we > only look for one device below a PCIe downstream > port. > + driver Provide an override to the devid<->driver mapping > + for a specific slot. > + Bind PCI slot 0001:02:03.4 to pci-stub by: > + driver[0001:02:03.4]=pci-stub > > pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power > Management. > diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c > index 73aef51..d2c0721 100644 > --- a/drivers/pci/bus.c > +++ b/drivers/pci/bus.c > @@ -230,6 +230,91 @@ EXPORT_SYMBOL(pci_bus_alloc_resource); > > void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { } > > +#define DRIVER_OVERRIDE_NAME_LENGTH 64 Do we know all drivers have shorter names? > + > +struct driver_override_entry { > + unsigned int domain; > + unsigned char bus; > + unsigned int devfn; > + char driver_name[DRIVER_OVERRIDE_NAME_LENGTH]; > + struct list_head list; > +}; > + > +static LIST_HEAD(driver_override_entries); > + > +static int pci_device_parse_driver_override(char *param, char *val, > + const char *unused) > +{ > + unsigned int domain, bus, dev, fn; > + char driver_name[DRIVER_OVERRIDE_NAME_LENGTH]; > + char format[] = "[%4x:%2x:%2x.%2x]=%%%ds"; > + struct driver_override_entry *entry; > + int ret; > + > + while (val) { > + char *k = strchr(val, ','); > + > + if (k) > + *k++ = 0; > + > + if (strncmp(val, "driver", 6)) { > + val = k; > + continue; > + } > + > + sprintf(format + 18, "%%%ds", DRIVER_OVERRIDE_NAME_LENGTH); > + ret = sscanf(val + 6, format, &domain, &bus, &dev, &fn, > + driver_name); > + if (ret != 5) { > + pr_err("PCI: Invalid command line: %s\n", val); > + val = k; > + continue; > + } > + > + entry = kzalloc(sizeof(*entry), GFP_KERNEL); > + BUG_ON(!entry); > + > + INIT_LIST_HEAD(&entry->list); > + entry->domain = domain; > + entry->bus = bus && 0xff; > + entry->devfn = ((dev & 0x1f) << 3) | (fn & 0x7); > + memcpy(entry->driver_name, driver_name, sizeof(driver_name)); > + > + list_add_tail(&entry->list, &driver_override_entries); > + val = k; > + } > + > + return 0; > +} > + > +static void pci_device_setup_driver_override(struct pci_dev *dev) > +{ > + static int parse_done; > + struct driver_override_entry *entry; > + > + if (!parse_done) { > + char *cmdline = kstrdup(saved_command_line, GFP_KERNEL); > + > + BUG_ON(!cmdline); > + > + parse_args("pci", cmdline, NULL, > + 0, 0, 0, &pci_device_parse_driver_override); > + kfree(cmdline); > + parse_done = 1; > + } > + > + list_for_each_entry(entry, &driver_override_entries, list) { > + if (pci_domain_nr(dev->bus) != entry->domain || > + dev->bus->number != entry->bus || > + dev->devfn != entry->devfn) > + continue; > + > + dev->driver_override = kstrdup(entry->driver_name, GFP_KERNEL); > + BUG_ON(!dev->driver_override); > + break; > + } > +} > + > /** > * pci_bus_add_device - start driver for a single device > * @dev: device to add > @@ -245,6 +330,7 @@ void pci_bus_add_device(struct pci_dev *dev) > * are not assigned yet for some devices. > */ > pci_fixup_device(pci_fixup_final, dev); > + pci_device_setup_driver_override(dev); > pci_create_sysfs_dev_files(dev); > pci_proc_attach_device(dev); > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index b7678be..6bd7844 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -4468,6 +4468,8 @@ static int __init pci_setup(char *str) > pcie_bus_config = PCIE_BUS_PEER2PEER; > } else if (!strncmp(str, "pcie_scan_all", 13)) { > pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS); > + } else if (!strncmp(str, "driver", 6)) { > + /* lazy evaluation by the pci subsystem */ > } else { > printk(KERN_ERR "PCI: Unknown option `%s'\n", > str); > -- > 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Tue, 2014-10-07 at 18:02 +0300, Michael S. Tsirkin wrote: > On Tue, Oct 07, 2014 at 05:48:32PM +0300, Marcel Apfelbaum wrote: > > Scanning a lot of devices during boot requires a lot of time. > > On other scenarios there is a need to bind a driver to a specific slot. > > > > Binding devices to pci-stub driver does not work, > > as it will not differentiate between devices of the > > same type. Using some start scripts is error prone. > > > > The solution leverages driver_override functionality introduced by > > > > commit: 782a985d7af26db39e86070d28f987cad21313c0 > > Author: Alex Williamson <alex.williamson@redhat.com> > > Date: Tue May 20 08:53:21 2014 -0600 > > > > PCI: Introduce new device binding path using pci_dev.driver_override > > > > In order to bind PCI slots to specific drivers use: > > pci=driver[xxxx:xx:xx.x]=foo,driver[xxxx:xx:xx.x]=bar,... > > > > Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com> > > --- > > v2 -> v3: > > - Corrected subject line > > v1 -> v2: > > - Addressed Michael S. Tsirkin comments > > - Removed 32 slots limitation > > - Better handling of memory allocation failures > > (preferred BUG_ON over error messages) > > - Addressed Alex Williamson's comments: > > - Modified commit message to show parameter usage more clear. > > - I preferred to re-use parse_args instead of manually using > > strstr in order to better comply with command line parsing > > rules. > > - I didn't use any locking when parsing the command line args > > (see parse_done usage) assuming that first call will be > > early in system boot and no race can occur. Please correct > > me if I am wrong. > > > > Notes: > > - I have further ideas on top of this patch based on your reviews. > > I thought of: > > - Use wildcards to specify entire buses/devices, something like: > > driver[0001:02:*.*]=pci-stub > > - Use comma to separate several devices: > > driver[0001:02:03.4,0001:02:04.0,...]=pci-stub > > - Make domain optional: > > driver[00:03.0]=pci-stub > > > > Comments will be appreciated, > > Thanks, > > Marcel > > Documentation/kernel-parameters.txt | 4 ++ > > drivers/pci/bus.c | 86 +++++++++++++++++++++++++++++++++++++ > > drivers/pci/pci.c | 2 + > > 3 files changed, 92 insertions(+) > > > > diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt > > index 5ae8608..c1cbb4c 100644 > > --- a/Documentation/kernel-parameters.txt > > +++ b/Documentation/kernel-parameters.txt > > @@ -2631,6 +2631,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. > > pcie_scan_all Scan all possible PCIe devices. Otherwise we > > only look for one device below a PCIe downstream > > port. > > + driver Provide an override to the devid<->driver mapping > > + for a specific slot. > > + Bind PCI slot 0001:02:03.4 to pci-stub by: > > + driver[0001:02:03.4]=pci-stub > > > > pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power > > Management. > > diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c > > index 73aef51..d2c0721 100644 > > --- a/drivers/pci/bus.c > > +++ b/drivers/pci/bus.c > > @@ -230,6 +230,91 @@ EXPORT_SYMBOL(pci_bus_alloc_resource); > > > > void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { } > > > > +#define DRIVER_OVERRIDE_NAME_LENGTH 64 > > Do we know all drivers have shorter names? Hi Michael, I saw this assumption in at least one place (sadly I don't remember where) and I chose to follow it. It seems a reasonable one in my opinion. Thanks, Marcel > > > + > > +struct driver_override_entry { > > + unsigned int domain; > > + unsigned char bus; > > + unsigned int devfn; > > + char driver_name[DRIVER_OVERRIDE_NAME_LENGTH]; > > + struct list_head list; > > +}; > > + > > +static LIST_HEAD(driver_override_entries); > > + > > +static int pci_device_parse_driver_override(char *param, char *val, > > + const char *unused) > > +{ > > + unsigned int domain, bus, dev, fn; > > + char driver_name[DRIVER_OVERRIDE_NAME_LENGTH]; > > + char format[] = "[%4x:%2x:%2x.%2x]=%%%ds"; > > + struct driver_override_entry *entry; > > + int ret; > > + > > + while (val) { > > + char *k = strchr(val, ','); > > + > > + if (k) > > + *k++ = 0; > > + > > + if (strncmp(val, "driver", 6)) { > > + val = k; > > + continue; > > + } > > + > > + sprintf(format + 18, "%%%ds", DRIVER_OVERRIDE_NAME_LENGTH); > > + ret = sscanf(val + 6, format, &domain, &bus, &dev, &fn, > > + driver_name); > > + if (ret != 5) { > > + pr_err("PCI: Invalid command line: %s\n", val); > > + val = k; > > + continue; > > + } > > + > > + entry = kzalloc(sizeof(*entry), GFP_KERNEL); > > + BUG_ON(!entry); > > + > > + INIT_LIST_HEAD(&entry->list); > > + entry->domain = domain; > > + entry->bus = bus && 0xff; > > + entry->devfn = ((dev & 0x1f) << 3) | (fn & 0x7); > > + memcpy(entry->driver_name, driver_name, sizeof(driver_name)); > > + > > + list_add_tail(&entry->list, &driver_override_entries); > > + val = k; > > + } > > + > > + return 0; > > +} > > + > > +static void pci_device_setup_driver_override(struct pci_dev *dev) > > +{ > > + static int parse_done; > > + struct driver_override_entry *entry; > > + > > + if (!parse_done) { > > + char *cmdline = kstrdup(saved_command_line, GFP_KERNEL); > > + > > + BUG_ON(!cmdline); > > + > > + parse_args("pci", cmdline, NULL, > > + 0, 0, 0, &pci_device_parse_driver_override); > > + kfree(cmdline); > > + parse_done = 1; > > + } > > + > > + list_for_each_entry(entry, &driver_override_entries, list) { > > + if (pci_domain_nr(dev->bus) != entry->domain || > > + dev->bus->number != entry->bus || > > + dev->devfn != entry->devfn) > > + continue; > > + > > + dev->driver_override = kstrdup(entry->driver_name, GFP_KERNEL); > > + BUG_ON(!dev->driver_override); > > + break; > > + } > > +} > > + > > /** > > * pci_bus_add_device - start driver for a single device > > * @dev: device to add > > @@ -245,6 +330,7 @@ void pci_bus_add_device(struct pci_dev *dev) > > * are not assigned yet for some devices. > > */ > > pci_fixup_device(pci_fixup_final, dev); > > + pci_device_setup_driver_override(dev); > > pci_create_sysfs_dev_files(dev); > > pci_proc_attach_device(dev); > > > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > > index b7678be..6bd7844 100644 > > --- a/drivers/pci/pci.c > > +++ b/drivers/pci/pci.c > > @@ -4468,6 +4468,8 @@ static int __init pci_setup(char *str) > > pcie_bus_config = PCIE_BUS_PEER2PEER; > > } else if (!strncmp(str, "pcie_scan_all", 13)) { > > pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS); > > + } else if (!strncmp(str, "driver", 6)) { > > + /* lazy evaluation by the pci subsystem */ > > } else { > > printk(KERN_ERR "PCI: Unknown option `%s'\n", > > str); > > -- > > 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 5ae8608..c1cbb4c 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2631,6 +2631,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted. pcie_scan_all Scan all possible PCIe devices. Otherwise we only look for one device below a PCIe downstream port. + driver Provide an override to the devid<->driver mapping + for a specific slot. + Bind PCI slot 0001:02:03.4 to pci-stub by: + driver[0001:02:03.4]=pci-stub pcie_aspm= [PCIE] Forcibly enable or disable PCIe Active State Power Management. diff --git a/drivers/pci/bus.c b/drivers/pci/bus.c index 73aef51..d2c0721 100644 --- a/drivers/pci/bus.c +++ b/drivers/pci/bus.c @@ -230,6 +230,91 @@ EXPORT_SYMBOL(pci_bus_alloc_resource); void __weak pcibios_resource_survey_bus(struct pci_bus *bus) { } +#define DRIVER_OVERRIDE_NAME_LENGTH 64 + +struct driver_override_entry { + unsigned int domain; + unsigned char bus; + unsigned int devfn; + char driver_name[DRIVER_OVERRIDE_NAME_LENGTH]; + struct list_head list; +}; + +static LIST_HEAD(driver_override_entries); + +static int pci_device_parse_driver_override(char *param, char *val, + const char *unused) +{ + unsigned int domain, bus, dev, fn; + char driver_name[DRIVER_OVERRIDE_NAME_LENGTH]; + char format[] = "[%4x:%2x:%2x.%2x]=%%%ds"; + struct driver_override_entry *entry; + int ret; + + while (val) { + char *k = strchr(val, ','); + + if (k) + *k++ = 0; + + if (strncmp(val, "driver", 6)) { + val = k; + continue; + } + + sprintf(format + 18, "%%%ds", DRIVER_OVERRIDE_NAME_LENGTH); + ret = sscanf(val + 6, format, &domain, &bus, &dev, &fn, + driver_name); + if (ret != 5) { + pr_err("PCI: Invalid command line: %s\n", val); + val = k; + continue; + } + + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + BUG_ON(!entry); + + INIT_LIST_HEAD(&entry->list); + entry->domain = domain; + entry->bus = bus && 0xff; + entry->devfn = ((dev & 0x1f) << 3) | (fn & 0x7); + memcpy(entry->driver_name, driver_name, sizeof(driver_name)); + + list_add_tail(&entry->list, &driver_override_entries); + val = k; + } + + return 0; +} + +static void pci_device_setup_driver_override(struct pci_dev *dev) +{ + static int parse_done; + struct driver_override_entry *entry; + + if (!parse_done) { + char *cmdline = kstrdup(saved_command_line, GFP_KERNEL); + + BUG_ON(!cmdline); + + parse_args("pci", cmdline, NULL, + 0, 0, 0, &pci_device_parse_driver_override); + kfree(cmdline); + parse_done = 1; + } + + list_for_each_entry(entry, &driver_override_entries, list) { + if (pci_domain_nr(dev->bus) != entry->domain || + dev->bus->number != entry->bus || + dev->devfn != entry->devfn) + continue; + + dev->driver_override = kstrdup(entry->driver_name, GFP_KERNEL); + BUG_ON(!dev->driver_override); + break; + } +} + /** * pci_bus_add_device - start driver for a single device * @dev: device to add @@ -245,6 +330,7 @@ void pci_bus_add_device(struct pci_dev *dev) * are not assigned yet for some devices. */ pci_fixup_device(pci_fixup_final, dev); + pci_device_setup_driver_override(dev); pci_create_sysfs_dev_files(dev); pci_proc_attach_device(dev); diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index b7678be..6bd7844 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4468,6 +4468,8 @@ static int __init pci_setup(char *str) pcie_bus_config = PCIE_BUS_PEER2PEER; } else if (!strncmp(str, "pcie_scan_all", 13)) { pci_add_flags(PCI_SCAN_ALL_PCIE_DEVS); + } else if (!strncmp(str, "driver", 6)) { + /* lazy evaluation by the pci subsystem */ } else { printk(KERN_ERR "PCI: Unknown option `%s'\n", str);
Scanning a lot of devices during boot requires a lot of time. On other scenarios there is a need to bind a driver to a specific slot. Binding devices to pci-stub driver does not work, as it will not differentiate between devices of the same type. Using some start scripts is error prone. The solution leverages driver_override functionality introduced by commit: 782a985d7af26db39e86070d28f987cad21313c0 Author: Alex Williamson <alex.williamson@redhat.com> Date: Tue May 20 08:53:21 2014 -0600 PCI: Introduce new device binding path using pci_dev.driver_override In order to bind PCI slots to specific drivers use: pci=driver[xxxx:xx:xx.x]=foo,driver[xxxx:xx:xx.x]=bar,... Signed-off-by: Marcel Apfelbaum <marcel.a@redhat.com> --- v2 -> v3: - Corrected subject line v1 -> v2: - Addressed Michael S. Tsirkin comments - Removed 32 slots limitation - Better handling of memory allocation failures (preferred BUG_ON over error messages) - Addressed Alex Williamson's comments: - Modified commit message to show parameter usage more clear. - I preferred to re-use parse_args instead of manually using strstr in order to better comply with command line parsing rules. - I didn't use any locking when parsing the command line args (see parse_done usage) assuming that first call will be early in system boot and no race can occur. Please correct me if I am wrong. Notes: - I have further ideas on top of this patch based on your reviews. I thought of: - Use wildcards to specify entire buses/devices, something like: driver[0001:02:*.*]=pci-stub - Use comma to separate several devices: driver[0001:02:03.4,0001:02:04.0,...]=pci-stub - Make domain optional: driver[00:03.0]=pci-stub Comments will be appreciated, Thanks, Marcel Documentation/kernel-parameters.txt | 4 ++ drivers/pci/bus.c | 86 +++++++++++++++++++++++++++++++++++++ drivers/pci/pci.c | 2 + 3 files changed, 92 insertions(+)