[PATCH] pci: dw_common: Set INCREASE_REGION_SIZE flag based on limit address

[Neil Armstrong]

Set the INCREASE_REGION_SIZE for the outbound iATU entry if it
causes the 4GB range overflow in order to activate the extended
limit address by means of an additional iATU CSR (upper limit
address register).

This is required to make PCIe host controller work on Qualcomm SoCs,
namely the SM8550 and SM8650.

Based on the Linux commit 777e7c3ab7303 that can be found at [1].

[1] https://lore.kernel.org/all/20220624143428.8334-5-Sergey.Semin@baikalelectronics.ru/

Signed-off-by: Neil Armstrong <neil.armstrong at linaro.org>
---
 drivers/pci/pcie_dw_common.c | 8 ++++++--
 drivers/pci/pcie_dw_common.h | 2 ++
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/pci/pcie_dw_common.c b/drivers/pci/pcie_dw_common.c
index 78961271a8eef8e4b6991675ee9de2bb1968b8da..5322f6bdaee450470d7f706bb4b4097a368ec455 100644
--- a/drivers/pci/pcie_dw_common.c
+++ b/drivers/pci/pcie_dw_common.c
@@ -78,8 +78,12 @@ int pcie_dw_prog_outbound_atu_unroll(struct pcie_dw *pci, int index,
 				 lower_32_bits(pci_addr));
 	dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_UPPER_TARGET,
 				 upper_32_bits(pci_addr));
-	dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_REGION_CTRL1,
-				 type);
+	if (upper_32_bits(cpu_addr + size - 1) > upper_32_bits(cpu_addr))
+		dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_REGION_CTRL1,
+					 type | PCIE_ATU_INCREASE_REGION_SIZE);
+	else
+		dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_REGION_CTRL1,
+					 type);
 	dw_pcie_writel_ob_unroll(pci, index, PCIE_ATU_UNR_REGION_CTRL2,
 				 PCIE_ATU_ENABLE);
 
diff --git a/drivers/pci/pcie_dw_common.h b/drivers/pci/pcie_dw_common.h
index 8cb99a12ea1a5fd3687f980cc1ff99839d06dbc2..748945f95975e8251cdb92a670e8d5bc575d2847 100644
--- a/drivers/pci/pcie_dw_common.h
+++ b/drivers/pci/pcie_dw_common.h
@@ -46,6 +46,8 @@
 #define PCIE_ATU_DEV(x)			(((x) & 0x1f) << 19)
 #define PCIE_ATU_FUNC(x)		(((x) & 0x7) << 16)
 
+#define PCIE_ATU_INCREASE_REGION_SIZE    BIT(13)
+
 /* Register address builder */
 #define PCIE_GET_ATU_OUTB_UNR_REG_OFFSET(region)	((region) << 9)
 

---
base-commit: b3c09eb36529fbb277bec17b35e638f42cb33683
change-id: 20250206-topic-sm8x50-pcie-dw-atu-increase-region-size-878465356c54

Best regards,
-- 
Neil Armstrong <neil.armstrong at linaro.org>