| Message ID | 20200110030112.188845-1-saravanak@google.com (mailing list archive) |
|---|---|
| State | Mainlined |
| Commit | 64c8a0cd0a535891d5905c3a1651150f0f141439 |
| Headers | show |
| Series | [v3] efi: arm: defer probe of PCIe backed efifb on DT systems | expand |
On Fri, 10 Jan 2020 at 04:01, Saravana Kannan <saravanak@google.com> wrote: > > From: Ard Biesheuvel <ardb@kernel.org> > > The new of_devlink support breaks PCIe probing on ARM platforms booting > via UEFI if the firmware exposes a EFI framebuffer that is backed by a > PCI device. The reason is that the probing order gets reversed, > resulting in a resource conflict on the framebuffer memory window when > the PCIe probes last, causing it to give up entirely. > > Given that we rely on PCI quirks to deal with EFI framebuffers that get > moved around in memory, we cannot simply drop the memory reservation, so > instead, let's use the device link infrastructure to register this > dependency, and force the probing to occur in the expected order. > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > Co-developed-by: Saravana Kannan <saravanak@google.com> > Signed-off-by: Saravana Kannan <saravanak@google.com> > Reviewed-by: Ard Biesheuvel <ardb@kernel.org> > --- > > v1 -> v2: > - Rewrote the device linking part to not depend on initcall ordering > v2 -> v3: > - Added const and check for CONFIG_PCI > Thanks. I've queued this version in efi/next for v5.6 > drivers/firmware/efi/arm-init.c | 107 ++++++++++++++++++++++++++++++-- > 1 file changed, 103 insertions(+), 4 deletions(-) > > diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c > index 904fa09e6a6b..d99f5b0c8a09 100644 > --- a/drivers/firmware/efi/arm-init.c > +++ b/drivers/firmware/efi/arm-init.c > @@ -10,10 +10,12 @@ > #define pr_fmt(fmt) "efi: " fmt > > #include <linux/efi.h> > +#include <linux/fwnode.h> > #include <linux/init.h> > #include <linux/memblock.h> > #include <linux/mm_types.h> > #include <linux/of.h> > +#include <linux/of_address.h> > #include <linux/of_fdt.h> > #include <linux/platform_device.h> > #include <linux/screen_info.h> > @@ -276,15 +278,112 @@ void __init efi_init(void) > efi_memmap_unmap(); > } > > +static bool efifb_overlaps_pci_range(const struct of_pci_range *range) > +{ > + u64 fb_base = screen_info.lfb_base; > + > + if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) > + fb_base |= (u64)(unsigned long)screen_info.ext_lfb_base << 32; > + > + return fb_base >= range->cpu_addr && > + fb_base < (range->cpu_addr + range->size); > +} > + > +static struct device_node *find_pci_overlap_node(void) > +{ > + struct device_node *np; > + > + for_each_node_by_type(np, "pci") { > + struct of_pci_range_parser parser; > + struct of_pci_range range; > + int err; > + > + err = of_pci_range_parser_init(&parser, np); > + if (err) { > + pr_warn("of_pci_range_parser_init() failed: %d\n", err); > + continue; > + } > + > + for_each_of_pci_range(&parser, &range) > + if (efifb_overlaps_pci_range(&range)) > + return np; > + } > + return NULL; > +} > + > +/* > + * If the efifb framebuffer is backed by a PCI graphics controller, we have > + * to ensure that this relation is expressed using a device link when > + * running in DT mode, or the probe order may be reversed, resulting in a > + * resource reservation conflict on the memory window that the efifb > + * framebuffer steals from the PCIe host bridge. > + */ > +static int efifb_add_links(const struct fwnode_handle *fwnode, > + struct device *dev) > +{ > + struct device_node *sup_np; > + struct device *sup_dev; > + > + sup_np = find_pci_overlap_node(); > + > + /* > + * If there's no PCI graphics controller backing the efifb, we are > + * done here. > + */ > + if (!sup_np) > + return 0; > + > + sup_dev = get_dev_from_fwnode(&sup_np->fwnode); > + of_node_put(sup_np); > + > + /* > + * Return -ENODEV if the PCI graphics controller device hasn't been > + * registered yet. This ensures that efifb isn't allowed to probe > + * and this function is retried again when new devices are > + * registered. > + */ > + if (!sup_dev) > + return -ENODEV; > + > + /* > + * If this fails, retrying this function at a later point won't > + * change anything. So, don't return an error after this. > + */ > + if (!device_link_add(dev, sup_dev, 0)) > + dev_warn(dev, "device_link_add() failed\n"); > + > + put_device(sup_dev); > + > + return 0; > +} > + > +static const struct fwnode_operations efifb_fwnode_ops = { > + .add_links = efifb_add_links, > +}; > + > +static struct fwnode_handle efifb_fwnode = { > + .ops = &efifb_fwnode_ops, > +}; > + > static int __init register_gop_device(void) > { > - void *pd; > + struct platform_device *pd; > + int err; > > if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI) > return 0; > > - pd = platform_device_register_data(NULL, "efi-framebuffer", 0, > - &screen_info, sizeof(screen_info)); > - return PTR_ERR_OR_ZERO(pd); > + pd = platform_device_alloc("efi-framebuffer", 0); > + if (!pd) > + return -ENOMEM; > + > + if (IS_ENABLED(CONFIG_PCI)) > + pd->dev.fwnode = &efifb_fwnode; > + > + err = platform_device_add_data(pd, &screen_info, sizeof(screen_info)); > + if (err) > + return err; > + > + return platform_device_add(pd); > } > subsys_initcall(register_gop_device); > -- > 2.25.0.rc1.283.g88dfdc4193-goog >
On Thu, Jan 9, 2020 at 10:41 PM Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote: > > On Fri, 10 Jan 2020 at 04:01, Saravana Kannan <saravanak@google.com> wrote: > > > > From: Ard Biesheuvel <ardb@kernel.org> > > > > The new of_devlink support breaks PCIe probing on ARM platforms booting > > via UEFI if the firmware exposes a EFI framebuffer that is backed by a > > PCI device. The reason is that the probing order gets reversed, > > resulting in a resource conflict on the framebuffer memory window when > > the PCIe probes last, causing it to give up entirely. > > > > Given that we rely on PCI quirks to deal with EFI framebuffers that get > > moved around in memory, we cannot simply drop the memory reservation, so > > instead, let's use the device link infrastructure to register this > > dependency, and force the probing to occur in the expected order. > > > > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > Signed-off-by: Ard Biesheuvel <ardb@kernel.org> > > Co-developed-by: Saravana Kannan <saravanak@google.com> > > Signed-off-by: Saravana Kannan <saravanak@google.com> > > Reviewed-by: Ard Biesheuvel <ardb@kernel.org> > > --- > > > > v1 -> v2: > > - Rewrote the device linking part to not depend on initcall ordering > > v2 -> v3: > > - Added const and check for CONFIG_PCI > > > > Thanks. I've queued this version in efi/next for v5.6 Awesome, thanks! -Saravana
diff --git a/drivers/firmware/efi/arm-init.c b/drivers/firmware/efi/arm-init.c index 904fa09e6a6b..d99f5b0c8a09 100644 --- a/drivers/firmware/efi/arm-init.c +++ b/drivers/firmware/efi/arm-init.c @@ -10,10 +10,12 @@ #define pr_fmt(fmt) "efi: " fmt #include <linux/efi.h> +#include <linux/fwnode.h> #include <linux/init.h> #include <linux/memblock.h> #include <linux/mm_types.h> #include <linux/of.h> +#include <linux/of_address.h> #include <linux/of_fdt.h> #include <linux/platform_device.h> #include <linux/screen_info.h> @@ -276,15 +278,112 @@ void __init efi_init(void) efi_memmap_unmap(); } +static bool efifb_overlaps_pci_range(const struct of_pci_range *range) +{ + u64 fb_base = screen_info.lfb_base; + + if (screen_info.capabilities & VIDEO_CAPABILITY_64BIT_BASE) + fb_base |= (u64)(unsigned long)screen_info.ext_lfb_base << 32; + + return fb_base >= range->cpu_addr && + fb_base < (range->cpu_addr + range->size); +} + +static struct device_node *find_pci_overlap_node(void) +{ + struct device_node *np; + + for_each_node_by_type(np, "pci") { + struct of_pci_range_parser parser; + struct of_pci_range range; + int err; + + err = of_pci_range_parser_init(&parser, np); + if (err) { + pr_warn("of_pci_range_parser_init() failed: %d\n", err); + continue; + } + + for_each_of_pci_range(&parser, &range) + if (efifb_overlaps_pci_range(&range)) + return np; + } + return NULL; +} + +/* + * If the efifb framebuffer is backed by a PCI graphics controller, we have + * to ensure that this relation is expressed using a device link when + * running in DT mode, or the probe order may be reversed, resulting in a + * resource reservation conflict on the memory window that the efifb + * framebuffer steals from the PCIe host bridge. + */ +static int efifb_add_links(const struct fwnode_handle *fwnode, + struct device *dev) +{ + struct device_node *sup_np; + struct device *sup_dev; + + sup_np = find_pci_overlap_node(); + + /* + * If there's no PCI graphics controller backing the efifb, we are + * done here. + */ + if (!sup_np) + return 0; + + sup_dev = get_dev_from_fwnode(&sup_np->fwnode); + of_node_put(sup_np); + + /* + * Return -ENODEV if the PCI graphics controller device hasn't been + * registered yet. This ensures that efifb isn't allowed to probe + * and this function is retried again when new devices are + * registered. + */ + if (!sup_dev) + return -ENODEV; + + /* + * If this fails, retrying this function at a later point won't + * change anything. So, don't return an error after this. + */ + if (!device_link_add(dev, sup_dev, 0)) + dev_warn(dev, "device_link_add() failed\n"); + + put_device(sup_dev); + + return 0; +} + +static const struct fwnode_operations efifb_fwnode_ops = { + .add_links = efifb_add_links, +}; + +static struct fwnode_handle efifb_fwnode = { + .ops = &efifb_fwnode_ops, +}; + static int __init register_gop_device(void) { - void *pd; + struct platform_device *pd; + int err; if (screen_info.orig_video_isVGA != VIDEO_TYPE_EFI) return 0; - pd = platform_device_register_data(NULL, "efi-framebuffer", 0, - &screen_info, sizeof(screen_info)); - return PTR_ERR_OR_ZERO(pd); + pd = platform_device_alloc("efi-framebuffer", 0); + if (!pd) + return -ENOMEM; + + if (IS_ENABLED(CONFIG_PCI)) + pd->dev.fwnode = &efifb_fwnode; + + err = platform_device_add_data(pd, &screen_info, sizeof(screen_info)); + if (err) + return err; + + return platform_device_add(pd); } subsys_initcall(register_gop_device);