Re: [PATCH v2 09/18] pci: Add config for Enhanced Allocation

On Wed, Mar 30, 2022 at 12:59 AM Andrew Scull ascull@google.com wrote:

Add a config to control whether Enhanced Allocation is supported by the driver.

Signed-off-by: Andrew Scull ascull@google.com

drivers/pci/Kconfig | 7 +++++++ drivers/pci/pci-uclass.c | 25 +++++++++++++++---------- 2 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index 47cd074aa1..fd2203420c 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -67,6 +67,13 @@ config PCI_SRIOV if available on a PCI Physical Function device and probe for applicable drivers.

+config PCI_ENHANCED_ALLOCATION

•   bool "Enable support for Enhanced Allocation of resources"
  

•   default y
  

•   help
  

•     Enable support for Enhanced Allocation which can be used by supported
  

•     devices in place of traditional BARS for allocation of resources.
  

Why do we need a config option for EA as it can be figured out in the run time?

config PCI_ARID bool "Enable Alternate Routing-ID support for PCI" help diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c index 8bbeb62f2e..719656eb3a 100644 --- a/drivers/pci/pci-uclass.c +++ b/drivers/pci/pci-uclass.c @@ -645,7 +645,11 @@ int dm_pci_hose_probe_bus(struct udevice *bus) return log_msg_ret("probe", -EINVAL); }

•   ea_pos = dm_pci_find_capability(bus, PCI_CAP_ID_EA);
  

•   if (IS_ENABLED(CONFIG_PCI_ENHANCED_ALLOCATION))
  

•           ea_pos = dm_pci_find_capability(bus, PCI_CAP_ID_EA);
  

•   else
  

•           ea_pos = 0;
  

•   if (ea_pos) {
            dm_pci_read_config8(bus, ea_pos + sizeof(u32) + sizeof(u8),
                                &reg);
  

@@ -1600,15 +1604,16 @@ void *dm_pci_map_bar(struct udevice *dev, int bar, unsigned long flags) udev = pdata->pfdev; }

•   /*
  

•    * if the function supports Enhanced Allocation use that instead of
  

•    * BARs
  

•    * Incase of virtual functions, pdata will help read VF BEI
  

•    * and EA entry size.
  

•    */
  

•   ea_off = dm_pci_find_capability(udev, PCI_CAP_ID_EA);
  

•   if (ea_off)
  

•           return dm_pci_map_ea_bar(udev, bar, ea_off, pdata);
  

•   if (IS_ENABLED(CONFIG_PCI_ENHANCED_ALLOCATION)) {
  

•           /*
  

•            * If the function supports Enhanced Allocation use that
  

•            * instead of BARs. Incase of virtual functions, pdata will
  

•            * help read VF BEI and EA entry size.
  

•            */
  

•           ea_off = dm_pci_find_capability(udev, PCI_CAP_ID_EA);
  

•           if (ea_off)
  

•                   return dm_pci_map_ea_bar(udev, bar, ea_off, pdata);
  

•   }
  
    /* read BAR address */
    dm_pci_read_config32(udev, bar, &bar_response);
  

--

Regards, Bin