On Wed, Oct 16, 2019 at 11:04:47AM -0600, Jon Derrick wrote:
> When some VMDs are enabled and others are not, it's difficult to
> determine which IIO stack corresponds to the enabled VMD.
>
> To assist userspace with management tasks, VMD BIOS will write the VMD
> instance number and socket number into the first enabled root port's IO
> Base/Limit registers prior to OS handoff. VMD driver can capture this
> information and expose it to userspace.
>
> Signed-off-by: Jon Derrick <jonathan.derrick@xxxxxxxxx>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
> ---
> drivers/pci/controller/vmd.c | 79 ++++++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 77 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
> index 959c7c7..dbe1bff 100644
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -98,6 +98,8 @@ struct vmd_dev {
> struct irq_domain *irq_domain;
> struct pci_bus *bus;
> u8 busn_start;
> + u8 socket_nr;
> + u8 instance_nr;
>
> struct dma_map_ops dma_ops;
> struct dma_domain dma_domain;
> @@ -543,6 +545,74 @@ static int vmd_pci_write(struct pci_bus *bus, unsigned int devfn, int reg,
> .write = vmd_pci_write,
> };
>
> +/**
> + * for_each_vmd_root_port - iterate over all enabled VMD Root Ports
> + * @vmd: &struct vmd_dev VMD device descriptor
> + * @rp: int iterator cursor
> + * @temp: u32 temporary value for config read
> + *
> + * VMD Root Ports are located in the VMD PCIe Domain at 00:[0-3].0, and config
> + * space can be determinately accessed through the VMD Config BAR. Because VMD
> + * Root Ports can be individually disabled, it's important to iterate for the
> + * first enabled Root Port as determined by reading the Vendor/Device register.
> + */
> +#define for_each_vmd_root_port(vmd, rp, temp) \
> + for (rp = 0; rp < 4; rp++) \
> + if (vmd_cfg_read(vmd, 0, PCI_DEVFN(root_port, 0), \
> + PCI_VENDOR_ID, 4, &temp) || \
> + temp == 0xffffffff) {} else
Nit: I do not think this macro is particularly helpful or easy to read.
I leave it up to you but I would turn this code (plus the inner loop in
vmd_parse_domain()) into a function, eg:
struct vmd_dev *vmd_find_first_root_port(..)
with the code in the macro above inlined. Up to you.
Thanks,
Lorenzo
> +static int vmd_parse_domain(struct vmd_dev *vmd)
> +{
> + int root_port, ret;
> + u32 temp, iobase;
> +
> + vmd->socket_nr = -1;
> + vmd->instance_nr = -1;
> +
> + for_each_vmd_root_port(vmd, root_port, temp) {
> + ret = vmd_cfg_read(vmd, 0, PCI_DEVFN(root_port, 0),
> + PCI_IO_BASE, 2, &iobase);
> + if (ret)
> + return ret;
> +
> + vmd->socket_nr = (iobase >> 4) & 0xf;
> + vmd->instance_nr = (iobase >> 14) & 0x3;
> +
> + /* First available will be used */
> + break;
> + }
> +
> + return 0;
> +}
> +
> +static ssize_t socket_nr_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct pci_dev *pdev = to_pci_dev(dev);
> + struct vmd_dev *vmd = pci_get_drvdata(pdev);
> +
> + return sprintf(buf, "%u\n", vmd->socket_nr);
> +}
> +static DEVICE_ATTR_RO(socket_nr);
> +
> +static ssize_t instance_nr_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct pci_dev *pdev = to_pci_dev(dev);
> + struct vmd_dev *vmd = pci_get_drvdata(pdev);
> +
> + return sprintf(buf, "%u\n", vmd->instance_nr);
> +}
> +static DEVICE_ATTR_RO(instance_nr);
> +
> +static struct attribute *vmd_dev_attrs[] = {
> + &dev_attr_socket_nr.attr,
> + &dev_attr_instance_nr.attr,
> + NULL
> +};
> +ATTRIBUTE_GROUPS(vmd_dev);
> +
> static void vmd_attach_resources(struct vmd_dev *vmd)
> {
> vmd->dev->resource[VMD_MEMBAR1].child = &vmd->resources[1];
> @@ -582,6 +652,11 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
> resource_size_t offset[2] = {0};
> resource_size_t membar2_offset = 0x2000;
> struct pci_bus *child;
> + int ret;
> +
> + ret = vmd_parse_domain(vmd);
> + if (ret)
> + return ret;
>
> /*
> * Shadow registers may exist in certain VMD device ids which allow
> @@ -591,7 +666,6 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
> */
> if (features & VMD_FEAT_HAS_MEMBAR_SHADOW) {
> u32 vmlock;
> - int ret;
>
> membar2_offset = MB2_SHADOW_OFFSET + MB2_SHADOW_SIZE;
> ret = pci_read_config_dword(vmd->dev, PCI_REG_VMLOCK, &vmlock);
> @@ -876,7 +950,8 @@ static int vmd_resume(struct device *dev)
> .probe = vmd_probe,
> .remove = vmd_remove,
> .driver = {
> - .pm = &vmd_dev_pm_ops,
> + .pm = &vmd_dev_pm_ops,
> + .dev_groups = vmd_dev_groups,
> },
> };
> module_pci_driver(vmd_drv);
> --
> 1.8.3.1
>
