Sharing PCI device with 2 different PCI drivers - linux-kernel

Question

I am writing pci driver to access the Intel device with ID PCI_DEVICE_ID_INTEL_BROADWELL_IMC_HA0., which is at ff:12.0 (device ID 0x6fa0).
But, turned out sbridge_edac driver was already installed and associated with that PCI device. This causes my pci_register_driver() to return error.
Is there a way to make my PCI driver use that PCI device if another driver already associated with it?
#define PCI_DEVICE_ID_INTEL_BROADWELL_IMC_HA0 0x6fa0
static const struct pci_device_id sbridge_pci_tbl[] = {
{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_SBRIDGE_IMC_HA0)},
{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_IBRIDGE_IMC_HA0_TA)},
{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_HASWELL_IMC_HA0)},
{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_BROADWELL_IMC_HA0)},
{PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_DEVICE_ID_INTEL_KNL_IMC_SAD0)},
{0,} /* 0 terminated list. */
};
MODULE_DEVICE_TABLE(pci, sbridge_pci_tbl);
static struct pci_driver discovery_pci_driver ={
.name = DRIVER_NAME,
.probe = discovery_probe,
.remove = discovery_remove,
.id_table = sbridge_pci_tbl,
};
static int __init discovery_init(void)
{
int res;
res = pci_register_driver(&discovery_pci_driver);
if(res<0) {
PERR("Adding driver to pci core failed\n");
return res;
}
return 0;
}
$lspci -x
ff:12.0 System peripheral: Intel Corporation Xeon E7 v4/Xeon E5 v4/Xeon E3 v4/Xeon D Home Agent 0
Subsystem: Intel Corporation Xeon E7 v4/Xeon E5 v4/Xeon E3 v4/Xeon D Home Agent 0
Kernel driver in use: sbridge_edac

Answer 1

Since you want to create your own driver and associate it with the Intel hardware you can do one of the following:
Remove the sbridge_edac driver from the kernel config and recompile. You could also add your driver at this time.
Create a startup script that unloads the sbridge_edac driver and then loads in your driver.
Extend the sbridge_edac driver with your functionality (edit their code).
Create a function in your user space code that determines what driver is running and call it accordingly. You would have to put your driver functionality in your user space code and work with the sbridge_edac. But other user programs could access this one program instead of a driver.