[PATCH] PCI/ACPI: Add Ampere Altra SOC MCFG quirk

[Tuan Phan]

Ampere Altra SOC supports only 32-bit ECAM reading. Therefore,
add an MCFG quirk for the platform.

Signed-off-by: Tuan Phan <tuanphan@xxxxxxxxxxxxxxxxxxxxxx>
---
 drivers/acpi/pci_mcfg.c  | 20 ++++++++++++++++++++
 drivers/pci/ecam.c       | 10 ++++++++++
 include/linux/pci-ecam.h |  1 +
 3 files changed, 31 insertions(+)

diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
index 54b36b7ad47d..e526571e0ebd 100644
--- a/drivers/acpi/pci_mcfg.c
+++ b/drivers/acpi/pci_mcfg.c
@@ -142,6 +142,26 @@ static struct mcfg_fixup mcfg_quirks[] = {
 	XGENE_V2_ECAM_MCFG(4, 0),
 	XGENE_V2_ECAM_MCFG(4, 1),
 	XGENE_V2_ECAM_MCFG(4, 2),
+
+#define ALTRA_ECAM_QUIRK(rev, seg) \
+	{ "Ampere", "Altra   ", rev, seg, MCFG_BUS_ANY, &pci_32b_read_ops }
+
+	ALTRA_ECAM_QUIRK(1, 0),
+	ALTRA_ECAM_QUIRK(1, 1),
+	ALTRA_ECAM_QUIRK(1, 2),
+	ALTRA_ECAM_QUIRK(1, 3),
+	ALTRA_ECAM_QUIRK(1, 4),
+	ALTRA_ECAM_QUIRK(1, 5),
+	ALTRA_ECAM_QUIRK(1, 6),
+	ALTRA_ECAM_QUIRK(1, 7),
+	ALTRA_ECAM_QUIRK(1, 8),
+	ALTRA_ECAM_QUIRK(1, 9),
+	ALTRA_ECAM_QUIRK(1, 10),
+	ALTRA_ECAM_QUIRK(1, 11),
+	ALTRA_ECAM_QUIRK(1, 12),
+	ALTRA_ECAM_QUIRK(1, 13),
+	ALTRA_ECAM_QUIRK(1, 14),
+	ALTRA_ECAM_QUIRK(1, 15),
 };
 
 static char mcfg_oem_id[ACPI_OEM_ID_SIZE];
diff --git a/drivers/pci/ecam.c b/drivers/pci/ecam.c
index 8f065a42fc1a..b54d32a31669 100644
--- a/drivers/pci/ecam.c
+++ b/drivers/pci/ecam.c
@@ -168,4 +168,14 @@ const struct pci_ecam_ops pci_32b_ops = {
 		.write		= pci_generic_config_write32,
 	}
 };
+
+/* ECAM ops for 32-bit read only (non-compliant) */
+const struct pci_ecam_ops pci_32b_read_ops = {
+	.bus_shift	= 20,
+	.pci_ops	= {
+		.map_bus	= pci_ecam_map_bus,
+		.read		= pci_generic_config_read32,
+		.write		= pci_generic_config_write,
+	}
+};
 #endif
diff --git a/include/linux/pci-ecam.h b/include/linux/pci-ecam.h
index 1af5cb02ef7f..033ce74f02e8 100644
--- a/include/linux/pci-ecam.h
+++ b/include/linux/pci-ecam.h
@@ -51,6 +51,7 @@ extern const struct pci_ecam_ops pci_generic_ecam_ops;
 
 #if defined(CONFIG_ACPI) && defined(CONFIG_PCI_QUIRKS)
 extern const struct pci_ecam_ops pci_32b_ops;	/* 32-bit accesses only */
+extern const struct pci_ecam_ops pci_32b_read_ops; /* 32-bit read only */
 extern const struct pci_ecam_ops hisi_pcie_ops;	/* HiSilicon */
 extern const struct pci_ecam_ops thunder_pem_ecam_ops; /* Cavium ThunderX 1.x & 2.x */
 extern const struct pci_ecam_ops pci_thunder_ecam_ops; /* Cavium ThunderX 1.x */
-- 
2.18.4