PCI/ACPI: Implement _HPX Type 3 Setting Record

The _HPX Type 3 Setting Record is intended to be more generic and allow
configuration of settings not possible with Type 2 records.  For example,
firmware could ensure that the completion timeout value is set accordingly
throughout the PCI tree.

Implement support for _HPX Type 3 Setting Records, which were added in the
ACPI 6.3 spec.

Link: https://lore.kernel.org/lkml/20190208162414.3996-4-mr.nuke.me@gmail.com
Signed-off-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

1 files changed, 114 insertions, 0 deletions

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index dce5ae39d0d8..ea6c1762d5c8 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2026,6 +2026,119 @@ static void program_hpp_type2(struct pci_dev *dev, struct hpp_type2 *hpp)
 	 */
 }
 
+static u16 hpx3_device_type(struct pci_dev *dev)
+{
+	u16 pcie_type = pci_pcie_type(dev);
+	const int pcie_to_hpx3_type[] = {
+		[PCI_EXP_TYPE_ENDPOINT]    = HPX_TYPE_ENDPOINT,
+		[PCI_EXP_TYPE_LEG_END]     = HPX_TYPE_LEG_END,
+		[PCI_EXP_TYPE_RC_END]      = HPX_TYPE_RC_END,
+		[PCI_EXP_TYPE_RC_EC]       = HPX_TYPE_RC_EC,
+		[PCI_EXP_TYPE_ROOT_PORT]   = HPX_TYPE_ROOT_PORT,
+		[PCI_EXP_TYPE_UPSTREAM]    = HPX_TYPE_UPSTREAM,
+		[PCI_EXP_TYPE_DOWNSTREAM]  = HPX_TYPE_DOWNSTREAM,
+		[PCI_EXP_TYPE_PCI_BRIDGE]  = HPX_TYPE_PCI_BRIDGE,
+		[PCI_EXP_TYPE_PCIE_BRIDGE] = HPX_TYPE_PCIE_BRIDGE,
+	};
+
+	if (pcie_type >= ARRAY_SIZE(pcie_to_hpx3_type))
+		return 0;
+
+	return pcie_to_hpx3_type[pcie_type];
+}
+
+static u8 hpx3_function_type(struct pci_dev *dev)
+{
+	if (dev->is_virtfn)
+		return HPX_FN_SRIOV_VIRT;
+	else if (pci_find_ext_capability(dev, PCI_EXT_CAP_ID_SRIOV) > 0)
+		return HPX_FN_SRIOV_PHYS;
+	else
+		return HPX_FN_NORMAL;
+}
+
+static bool hpx3_cap_ver_matches(u8 pcie_cap_id, u8 hpx3_cap_id)
+{
+	u8 cap_ver = hpx3_cap_id & 0xf;
+
+	if ((hpx3_cap_id & BIT(4)) && cap_ver >= pcie_cap_id)
+		return true;
+	else if (cap_ver == pcie_cap_id)
+		return true;
+
+	return false;
+}
+
+static void program_hpx_type3_register(struct pci_dev *dev,
+				       const struct hpx_type3 *reg)
+{
+	u32 match_reg, write_reg, header, orig_value;
+	u16 pos;
+
+	if (!(hpx3_device_type(dev) & reg->device_type))
+		return;
+
+	if (!(hpx3_function_type(dev) & reg->function_type))
+		return;
+
+	switch (reg->config_space_location) {
+	case HPX_CFG_PCICFG:
+		pos = 0;
+		break;
+	case HPX_CFG_PCIE_CAP:
+		pos = pci_find_capability(dev, reg->pci_exp_cap_id);
+		if (pos == 0)
+			return;
+
+		break;
+	case HPX_CFG_PCIE_CAP_EXT:
+		pos = pci_find_ext_capability(dev, reg->pci_exp_cap_id);
+		if (pos == 0)
+			return;
+
+		pci_read_config_dword(dev, pos, &header);
+		if (!hpx3_cap_ver_matches(PCI_EXT_CAP_VER(header),
+					  reg->pci_exp_cap_ver))
+			return;
+
+		break;
+	case HPX_CFG_VEND_CAP:	/* Fall through */
+	case HPX_CFG_DVSEC:	/* Fall through */
+	default:
+		pci_warn(dev, "Encountered _HPX type 3 with unsupported config space location");
+		return;
+	}
+
+	pci_read_config_dword(dev, pos + reg->match_offset, &match_reg);
+
+	if ((match_reg & reg->match_mask_and) != reg->match_value)
+		return;
+
+	pci_read_config_dword(dev, pos + reg->reg_offset, &write_reg);
+	orig_value = write_reg;
+	write_reg &= reg->reg_mask_and;
+	write_reg |= reg->reg_mask_or;
+
+	if (orig_value == write_reg)
+		return;
+
+	pci_write_config_dword(dev, pos + reg->reg_offset, write_reg);
+
+	pci_dbg(dev, "Applied _HPX3 at [0x%x]: 0x%08x -> 0x%08x",
+		pos, orig_value, write_reg);
+}
+
+static void program_hpx_type3(struct pci_dev *dev, struct hpx_type3 *hpx3)
+{
+	if (!hpx3)
+		return;
+
+	if (!pci_is_pcie(dev))
+		return;
+
+	program_hpx_type3_register(dev, hpx3);
+}
+
 int pci_configure_extended_tags(struct pci_dev *dev, void *ign)
 {
 	struct pci_host_bridge *host;
@@ -2210,6 +2323,7 @@ static void pci_configure_device(struct pci_dev *dev)
 		.program_type0 = program_hpp_type0,
 		.program_type1 = program_hpp_type1,
 		.program_type2 = program_hpp_type2,
+		.program_type3 = program_hpx_type3,
 	};
 
 	pci_configure_mps(dev);