[PATCH v10 0/4] PCI: dwc: Add ECAM support with iATU configuration

[PATCH v10 0/4] PCI: dwc: Add ECAM support with iATU configuration

[Manivannan Sadhasivam]

The current implementation requires iATU for every configuration
space access which increases latency & cpu utilization.

Designware databook 5.20a, section 3.10.10.3 says about CFG Shift Feature,
which shifts/maps the BDF (bits [31:16] of the third header DWORD, which
would be matched against the Base and Limit addresses) of the incoming
CfgRd0/CfgWr0 down to bits[27:12]of the translated address.

Configuring iATU in config shift mode enables ECAM feature to access the
config space, which avoids iATU configuration for every config access.

Add cfg_shft_mode into struct dw_pcie_ob_atu_cfg to enable config shift mode.

As DBI comes under config space, this avoids remapping of DBI space
separately. Instead, it uses the mapped config space address returned from
ECAM initialization. Change the order of dw_pcie_get_resources() execution
to acheive this.

Enable the ECAM feature if the config space size is equal to size required
to represent number of buses in the bus range property.

ELBI registers are optional registers which are part of dwc. So move
ELBI resource mapping to dwc. Also change the dtbinding and devicetree
to make the elbi registers as optional one. Having ELBI as the required
one is making the ecam feature complicated.

The ELBI registers falls after the DBI space, PARF_SLV_DBI_ELBI register
gives us the offset from which ELBI starts. so use this offset and cfg
win to map these regions instead of doing the ioremap again.

On root bus, we have only the root port. Any access other than that
should not go out of the link and should return all F's. Since the iATU
is configured for the buses which starts after root bus, block the
transactions starting from function 1 of the root bus to the end of
the root bus (i.e from dbi_base + 4kb to dbi_base + 1MB) from going
outside the link through ECAM blocker through PARF registers.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
---
Changes in v10:
- Moved qcom_pci_config_ecam() to qcom_pcie_host_init()
- Reworded the comment in patch 3
- Rebased on top of pci/controller/qcom 
- Link to v9: https://lore.kernel.org/r/20250909-controller-dwc-ecam-v9-0-7d5b651840dd@kernel.org

Changes in v9:
 - Splitted the ECAM enablement change to avoid bisect hole and excluded pcie-al
   driver from DWC ECAM since it uses its own ECAM mechanism.
 - Squashed the patches 2 and 3 as patch 2 won't work without 3.

For the rest of the history, please refer v8 changeset:
https://lore.kernel.org/linux-pci/20250828-ecam_v4-v8-0-92a30e0fa02d@oss.qualcomm.com

---
Krishna Chaitanya Chundru (4):
      PCI: dwc: Add support for ELBI resource mapping
      PCI: dwc: Prepare the driver for enabling ECAM mechanism using iATU 'CFG Shift Feature'
      PCI: qcom: Prepare for the DWC ECAM enablement
      PCI: dwc: Support ECAM mechanism by enabling iATU 'CFG Shift Feature'

 drivers/pci/controller/dwc/Kconfig                |   1 +
 drivers/pci/controller/dwc/pci-exynos.c           |  62 ++++-----
 drivers/pci/controller/dwc/pcie-al.c              |   1 +
 drivers/pci/controller/dwc/pcie-designware-host.c | 148 ++++++++++++++++++++--
 drivers/pci/controller/dwc/pcie-designware.c      |  10 +-
 drivers/pci/controller/dwc/pcie-designware.h      |   7 +
 drivers/pci/controller/dwc/pcie-qcom-ep.c         |  15 +--
 drivers/pci/controller/dwc/pcie-qcom.c            |  84 ++++++++++--
 8 files changed, 261 insertions(+), 67 deletions(-)
---
base-commit: af8df709bf365f5583d31091280354e1ef0b201f
change-id: 20250908-controller-dwc-ecam-4c7c3136de14

Best regards,
-- 
Manivannan Sadhasivam <mani@kernel.org>

[PATCH v10 1/4] PCI: dwc: Add support for ELBI resource mapping

[Manivannan Sadhasivam]

From: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>

External Local Bus Interface (ELBI) is an optional register space for all
DWC IPs containing the vendor specific registers. There is no need for the
vendor glue drivers to fetch and map the ELBI region separately.

Hence, optionally fetch and map the resource from DT in the DWC core. This
also warrants dropping the corresponding code from glue drivers. Hence,
drop the ELBI resource fetch and map logic from glue drivers and convert
them to use 'dw_pci::elbi_base'.

Note that the pcie-qcom-ep driver used devm_pci_remap_cfg_resource() to map
the ELBI resource previously. But it was a mistake since
devm_pci_remap_cfg_resource() should only be used for mapping the PCIe
config space region as it maps the region as Non-Posted. As ELBI is used to
hold vendor specific registers, there is no need to map the region as
Non-Posted. With this conversion, the region will get mapped as normal MMIO
memory.

Suggested-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
[mani: removed elbi override, converted glue drivers and reworded description]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
---
 drivers/pci/controller/dwc/pci-exynos.c      | 62 ++++++++++++++--------------
 drivers/pci/controller/dwc/pcie-designware.c |  8 ++++
 drivers/pci/controller/dwc/pcie-designware.h |  1 +
 drivers/pci/controller/dwc/pcie-qcom-ep.c    | 15 ++-----
 drivers/pci/controller/dwc/pcie-qcom.c       | 16 ++++---
 5 files changed, 50 insertions(+), 52 deletions(-)

diff --git a/drivers/pci/controller/dwc/pci-exynos.c b/drivers/pci/controller/dwc/pci-exynos.c
index 1f0e98d07109353e7321667e98ead2695151184c..0bb7d4f5d7840eaed75b2ba0884f045e4d1c6d2f 100644
--- a/drivers/pci/controller/dwc/pci-exynos.c
+++ b/drivers/pci/controller/dwc/pci-exynos.c
@@ -53,7 +53,6 @@
 
 struct exynos_pcie {
 	struct dw_pcie			pci;
-	void __iomem			*elbi_base;
 	struct clk_bulk_data		*clks;
 	struct phy			*phy;
 	struct regulator_bulk_data	supplies[2];
@@ -71,73 +70,78 @@ static u32 exynos_pcie_readl(void __iomem *base, u32 reg)
 
 static void exynos_pcie_sideband_dbi_w_mode(struct exynos_pcie *ep, bool on)
 {
+	struct dw_pcie *pci = &ep->pci;
 	u32 val;
 
-	val = exynos_pcie_readl(ep->elbi_base, PCIE_ELBI_SLV_AWMISC);
+	val = exynos_pcie_readl(pci->elbi_base, PCIE_ELBI_SLV_AWMISC);
 	if (on)
 		val |= PCIE_ELBI_SLV_DBI_ENABLE;
 	else
 		val &= ~PCIE_ELBI_SLV_DBI_ENABLE;
-	exynos_pcie_writel(ep->elbi_base, val, PCIE_ELBI_SLV_AWMISC);
+	exynos_pcie_writel(pci->elbi_base, val, PCIE_ELBI_SLV_AWMISC);
 }
 
 static void exynos_pcie_sideband_dbi_r_mode(struct exynos_pcie *ep, bool on)
 {
+	struct dw_pcie *pci = &ep->pci;
 	u32 val;
 
-	val = exynos_pcie_readl(ep->elbi_base, PCIE_ELBI_SLV_ARMISC);
+	val = exynos_pcie_readl(pci->elbi_base, PCIE_ELBI_SLV_ARMISC);
 	if (on)
 		val |= PCIE_ELBI_SLV_DBI_ENABLE;
 	else
 		val &= ~PCIE_ELBI_SLV_DBI_ENABLE;
-	exynos_pcie_writel(ep->elbi_base, val, PCIE_ELBI_SLV_ARMISC);
+	exynos_pcie_writel(pci->elbi_base, val, PCIE_ELBI_SLV_ARMISC);
 }
 
 static void exynos_pcie_assert_core_reset(struct exynos_pcie *ep)
 {
+	struct dw_pcie *pci = &ep->pci;
 	u32 val;
 
-	val = exynos_pcie_readl(ep->elbi_base, PCIE_CORE_RESET);
+	val = exynos_pcie_readl(pci->elbi_base, PCIE_CORE_RESET);
 	val &= ~PCIE_CORE_RESET_ENABLE;
-	exynos_pcie_writel(ep->elbi_base, val, PCIE_CORE_RESET);
-	exynos_pcie_writel(ep->elbi_base, 0, PCIE_STICKY_RESET);
-	exynos_pcie_writel(ep->elbi_base, 0, PCIE_NONSTICKY_RESET);
+	exynos_pcie_writel(pci->elbi_base, val, PCIE_CORE_RESET);
+	exynos_pcie_writel(pci->elbi_base, 0, PCIE_STICKY_RESET);
+	exynos_pcie_writel(pci->elbi_base, 0, PCIE_NONSTICKY_RESET);
 }
 
 static void exynos_pcie_deassert_core_reset(struct exynos_pcie *ep)
 {
+	struct dw_pcie *pci = &ep->pci;
 	u32 val;
 
-	val = exynos_pcie_readl(ep->elbi_base, PCIE_CORE_RESET);
+	val = exynos_pcie_readl(pci->elbi_base, PCIE_CORE_RESET);
 	val |= PCIE_CORE_RESET_ENABLE;
 
-	exynos_pcie_writel(ep->elbi_base, val, PCIE_CORE_RESET);
-	exynos_pcie_writel(ep->elbi_base, 1, PCIE_STICKY_RESET);
-	exynos_pcie_writel(ep->elbi_base, 1, PCIE_NONSTICKY_RESET);
-	exynos_pcie_writel(ep->elbi_base, 1, PCIE_APP_INIT_RESET);
-	exynos_pcie_writel(ep->elbi_base, 0, PCIE_APP_INIT_RESET);
+	exynos_pcie_writel(pci->elbi_base, val, PCIE_CORE_RESET);
+	exynos_pcie_writel(pci->elbi_base, 1, PCIE_STICKY_RESET);
+	exynos_pcie_writel(pci->elbi_base, 1, PCIE_NONSTICKY_RESET);
+	exynos_pcie_writel(pci->elbi_base, 1, PCIE_APP_INIT_RESET);
+	exynos_pcie_writel(pci->elbi_base, 0, PCIE_APP_INIT_RESET);
 }
 
 static int exynos_pcie_start_link(struct dw_pcie *pci)
 {
-	struct exynos_pcie *ep = to_exynos_pcie(pci);
 	u32 val;
 
-	val = exynos_pcie_readl(ep->elbi_base, PCIE_SW_WAKE);
+	val = exynos_pcie_readl(pci->elbi_base, PCIE_SW_WAKE);
 	val &= ~PCIE_BUS_EN;
-	exynos_pcie_writel(ep->elbi_base, val, PCIE_SW_WAKE);
+	exynos_pcie_writel(pci->elbi_base, val, PCIE_SW_WAKE);
 
 	/* assert LTSSM enable */
-	exynos_pcie_writel(ep->elbi_base, PCIE_ELBI_LTSSM_ENABLE,
+	exynos_pcie_writel(pci->elbi_base, PCIE_ELBI_LTSSM_ENABLE,
 			  PCIE_APP_LTSSM_ENABLE);
 	return 0;
 }
 
 static void exynos_pcie_clear_irq_pulse(struct exynos_pcie *ep)
 {
-	u32 val = exynos_pcie_readl(ep->elbi_base, PCIE_IRQ_PULSE);
+	struct dw_pcie *pci = &ep->pci;
 
-	exynos_pcie_writel(ep->elbi_base, val, PCIE_IRQ_PULSE);
+	u32 val = exynos_pcie_readl(pci->elbi_base, PCIE_IRQ_PULSE);
+
+	exynos_pcie_writel(pci->elbi_base, val, PCIE_IRQ_PULSE);
 }
 
 static irqreturn_t exynos_pcie_irq_handler(int irq, void *arg)
@@ -150,12 +154,14 @@ static irqreturn_t exynos_pcie_irq_handler(int irq, void *arg)
 
 static void exynos_pcie_enable_irq_pulse(struct exynos_pcie *ep)
 {
+	struct dw_pcie *pci = &ep->pci;
+
 	u32 val = IRQ_INTA_ASSERT | IRQ_INTB_ASSERT |
 		  IRQ_INTC_ASSERT | IRQ_INTD_ASSERT;
 
-	exynos_pcie_writel(ep->elbi_base, val, PCIE_IRQ_EN_PULSE);
-	exynos_pcie_writel(ep->elbi_base, 0, PCIE_IRQ_EN_LEVEL);
-	exynos_pcie_writel(ep->elbi_base, 0, PCIE_IRQ_EN_SPECIAL);
+	exynos_pcie_writel(pci->elbi_base, val, PCIE_IRQ_EN_PULSE);
+	exynos_pcie_writel(pci->elbi_base, 0, PCIE_IRQ_EN_LEVEL);
+	exynos_pcie_writel(pci->elbi_base, 0, PCIE_IRQ_EN_SPECIAL);
 }
 
 static u32 exynos_pcie_read_dbi(struct dw_pcie *pci, void __iomem *base,
@@ -211,8 +217,7 @@ static struct pci_ops exynos_pci_ops = {
 
 static bool exynos_pcie_link_up(struct dw_pcie *pci)
 {
-	struct exynos_pcie *ep = to_exynos_pcie(pci);
-	u32 val = exynos_pcie_readl(ep->elbi_base, PCIE_ELBI_RDLH_LINKUP);
+	u32 val = exynos_pcie_readl(pci->elbi_base, PCIE_ELBI_RDLH_LINKUP);
 
 	return val & PCIE_ELBI_XMLH_LINKUP;
 }
@@ -295,11 +300,6 @@ static int exynos_pcie_probe(struct platform_device *pdev)
 	if (IS_ERR(ep->phy))
 		return PTR_ERR(ep->phy);
 
-	/* External Local Bus interface (ELBI) registers */
-	ep->elbi_base = devm_platform_ioremap_resource_byname(pdev, "elbi");
-	if (IS_ERR(ep->elbi_base))
-		return PTR_ERR(ep->elbi_base);
-
 	ret = devm_clk_bulk_get_all_enabled(dev, &ep->clks);
 	if (ret < 0)
 		return ret;
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 89aad5a08928cc29870ab258d33bee9ff8f83143..93da8a26c9313dfdd6b269a90bbfb017aab2abe7 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -167,6 +167,14 @@ int dw_pcie_get_resources(struct dw_pcie *pci)
 		}
 	}
 
+	/* ELBI is an optional resource */
+	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "elbi");
+	if (res) {
+		pci->elbi_base = devm_ioremap_resource(pci->dev, res);
+		if (IS_ERR(pci->elbi_base))
+			return PTR_ERR(pci->elbi_base);
+	}
+
 	/* LLDD is supposed to manually switch the clocks and resets state */
 	if (dw_pcie_cap_is(pci, REQ_RES)) {
 		ret = dw_pcie_get_clocks(pci);
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 2418214730e4a2d065651f177bb64530b5d4f88b..9eb3c4c762ddca7d6faff3a98a54b37d7cd9f11b 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -491,6 +491,7 @@ struct dw_pcie {
 	resource_size_t		dbi_phys_addr;
 	void __iomem		*dbi_base2;
 	void __iomem		*atu_base;
+	void __iomem		*elbi_base;
 	resource_size_t		atu_phys_addr;
 	size_t			atu_size;
 	resource_size_t		parent_bus_offset;
diff --git a/drivers/pci/controller/dwc/pcie-qcom-ep.c b/drivers/pci/controller/dwc/pcie-qcom-ep.c
index aaf060bf39d40b6927e190b0aba5a86dcd320d0d..d7a7e278f6821dc7976f96982607564fb2f42169 100644
--- a/drivers/pci/controller/dwc/pcie-qcom-ep.c
+++ b/drivers/pci/controller/dwc/pcie-qcom-ep.c
@@ -179,7 +179,6 @@ struct qcom_pcie_ep_cfg {
  * struct qcom_pcie_ep - Qualcomm PCIe Endpoint Controller
  * @pci: Designware PCIe controller struct
  * @parf: Qualcomm PCIe specific PARF register base
- * @elbi: Designware PCIe specific ELBI register base
  * @mmio: MMIO register base
  * @perst_map: PERST regmap
  * @mmio_res: MMIO region resource
@@ -202,7 +201,6 @@ struct qcom_pcie_ep {
 	struct dw_pcie pci;
 
 	void __iomem *parf;
-	void __iomem *elbi;
 	void __iomem *mmio;
 	struct regmap *perst_map;
 	struct resource *mmio_res;
@@ -267,10 +265,9 @@ static void qcom_pcie_ep_configure_tcsr(struct qcom_pcie_ep *pcie_ep)
 
 static bool qcom_pcie_dw_link_up(struct dw_pcie *pci)
 {
-	struct qcom_pcie_ep *pcie_ep = to_pcie_ep(pci);
 	u32 reg;
 
-	reg = readl_relaxed(pcie_ep->elbi + ELBI_SYS_STTS);
+	reg = readl_relaxed(pci->elbi_base + ELBI_SYS_STTS);
 
 	return reg & XMLH_LINK_UP;
 }
@@ -294,16 +291,15 @@ static void qcom_pcie_dw_stop_link(struct dw_pcie *pci)
 static void qcom_pcie_dw_write_dbi2(struct dw_pcie *pci, void __iomem *base,
 				    u32 reg, size_t size, u32 val)
 {
-	struct qcom_pcie_ep *pcie_ep = to_pcie_ep(pci);
 	int ret;
 
-	writel(1, pcie_ep->elbi + ELBI_CS2_ENABLE);
+	writel(1, pci->elbi_base + ELBI_CS2_ENABLE);
 
 	ret = dw_pcie_write(pci->dbi_base2 + reg, size, val);
 	if (ret)
 		dev_err(pci->dev, "Failed to write DBI2 register (0x%x): %d\n", reg, ret);
 
-	writel(0, pcie_ep->elbi + ELBI_CS2_ENABLE);
+	writel(0, pci->elbi_base + ELBI_CS2_ENABLE);
 }
 
 static void qcom_pcie_ep_icc_update(struct qcom_pcie_ep *pcie_ep)
@@ -583,11 +579,6 @@ static int qcom_pcie_ep_get_io_resources(struct platform_device *pdev,
 		return PTR_ERR(pci->dbi_base);
 	pci->dbi_base2 = pci->dbi_base;
 
-	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "elbi");
-	pcie_ep->elbi = devm_pci_remap_cfg_resource(dev, res);
-	if (IS_ERR(pcie_ep->elbi))
-		return PTR_ERR(pcie_ep->elbi);
-
 	pcie_ep->mmio_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
 							 "mmio");
 	if (!pcie_ep->mmio_res) {
diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index 15d71109a2f7d45ea2184728360d1f3db8e8f3c6..c48a20602d7fa4c50056ccf6502d3b5bf0a8287f 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -276,7 +276,6 @@ struct qcom_pcie_port {
 struct qcom_pcie {
 	struct dw_pcie *pci;
 	void __iomem *parf;			/* DT parf */
-	void __iomem *elbi;			/* DT elbi */
 	void __iomem *mhi;
 	union qcom_pcie_resources res;
 	struct icc_path *icc_mem;
@@ -409,12 +408,17 @@ static void qcom_pcie_configure_dbi_atu_base(struct qcom_pcie *pcie)
 
 static void qcom_pcie_2_1_0_ltssm_enable(struct qcom_pcie *pcie)
 {
+	struct dw_pcie *pci = pcie->pci;
 	u32 val;
 
+	if (!pci->elbi_base) {
+		dev_err(pci->dev, "ELBI is not present\n");
+		return;
+	}
 	/* enable link training */
-	val = readl(pcie->elbi + ELBI_SYS_CTRL);
+	val = readl(pci->elbi_base + ELBI_SYS_CTRL);
 	val |= ELBI_SYS_CTRL_LT_ENABLE;
-	writel(val, pcie->elbi + ELBI_SYS_CTRL);
+	writel(val, pci->elbi_base + ELBI_SYS_CTRL);
 }
 
 static int qcom_pcie_get_resources_2_1_0(struct qcom_pcie *pcie)
@@ -1847,12 +1851,6 @@ static int qcom_pcie_probe(struct platform_device *pdev)
 		goto err_pm_runtime_put;
 	}
 
-	pcie->elbi = devm_platform_ioremap_resource_byname(pdev, "elbi");
-	if (IS_ERR(pcie->elbi)) {
-		ret = PTR_ERR(pcie->elbi);
-		goto err_pm_runtime_put;
-	}
-
 	/* MHI region is optional */
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "mhi");
 	if (res) {

-- 
2.48.1

[PATCH v10 2/4] PCI: dwc: Prepare the driver for enabling ECAM mechanism using iATU 'CFG Shift Feature'

[Manivannan Sadhasivam]

From: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>

In order to enable PCIe ECAM mechanism in DWC driver as per the 'CFG Shift
Feature' documented in Designware databook r5.20a, sec 3.10.10.3, prepare
the driver to handle the one time iATU setup and creating ECAM window.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
[mani: splitted the preparatory code into a separate commit for bisectability]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
---
 drivers/pci/controller/dwc/Kconfig                |   1 +
 drivers/pci/controller/dwc/pcie-designware-host.c | 116 +++++++++++++++++++---
 drivers/pci/controller/dwc/pcie-designware.c      |   2 +-
 drivers/pci/controller/dwc/pcie-designware.h      |   5 +
 4 files changed, 109 insertions(+), 15 deletions(-)

diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig
index deafc512b07928e30e93b814ad325a6be7dbcf75..dc0271203909fbcfa2b47733693d99b7a069426b 100644
--- a/drivers/pci/controller/dwc/Kconfig
+++ b/drivers/pci/controller/dwc/Kconfig
@@ -20,6 +20,7 @@ config PCIE_DW_HOST
 	bool
 	select PCIE_DW
 	select IRQ_MSI_LIB
+	select PCI_HOST_COMMON
 
 config PCIE_DW_EP
 	bool
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 952f8594b501254d2b2de5d5e056e16d2aa8d4b7..94e0fe11a0b062d0f14e09fe586e20bde46a4266 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -413,6 +413,67 @@ static void dw_pcie_host_request_msg_tlp_res(struct dw_pcie_rp *pp)
 	}
 }
 
+static int dw_pcie_config_ecam_iatu(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct dw_pcie_ob_atu_cfg atu = {0};
+	resource_size_t bus_range_max;
+	struct resource_entry *bus;
+	int ret;
+
+	bus = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS);
+
+	/*
+	 * Root bus under the host bridge doesn't require any iATU configuration
+	 * as DBI region will be used to access root bus config space.
+	 * Immediate bus under Root Bus, needs type 0 iATU configuration and
+	 * remaining buses need type 1 iATU configuration.
+	 */
+	atu.index = 0;
+	atu.type = PCIE_ATU_TYPE_CFG0;
+	atu.parent_bus_addr = pp->cfg0_base + SZ_1M;
+	/* 1MiB is to cover 1 (bus) * 32 (devices) * 8 (functions) */
+	atu.size = SZ_1M;
+	atu.ctrl2 = PCIE_ATU_CFG_SHIFT_MODE_ENABLE;
+	ret = dw_pcie_prog_outbound_atu(pci, &atu);
+	if (ret)
+		return ret;
+
+	bus_range_max = resource_size(bus->res);
+
+	if (bus_range_max < 2)
+		return 0;
+
+	/* Configure remaining buses in type 1 iATU configuration */
+	atu.index = 1;
+	atu.type = PCIE_ATU_TYPE_CFG1;
+	atu.parent_bus_addr = pp->cfg0_base + SZ_2M;
+	atu.size = (SZ_1M * bus_range_max) - SZ_2M;
+	atu.ctrl2 = PCIE_ATU_CFG_SHIFT_MODE_ENABLE;
+
+	return dw_pcie_prog_outbound_atu(pci, &atu);
+}
+
+static int dw_pcie_create_ecam_window(struct dw_pcie_rp *pp, struct resource *res)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct device *dev = pci->dev;
+	struct resource_entry *bus;
+
+	bus = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS);
+	if (!bus)
+		return -ENODEV;
+
+	pp->cfg = pci_ecam_create(dev, res, bus->res, &pci_generic_ecam_ops);
+	if (IS_ERR(pp->cfg))
+		return PTR_ERR(pp->cfg);
+
+	pci->dbi_base = pp->cfg->win;
+	pci->dbi_phys_addr = res->start;
+
+	return 0;
+}
+
 static int dw_pcie_host_get_resources(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -422,10 +483,6 @@ static int dw_pcie_host_get_resources(struct dw_pcie_rp *pp)
 	struct resource *res;
 	int ret;
 
-	ret = dw_pcie_get_resources(pci);
-	if (ret)
-		return ret;
-
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "config");
 	if (!res) {
 		dev_err(dev, "Missing \"config\" reg space\n");
@@ -435,9 +492,31 @@ static int dw_pcie_host_get_resources(struct dw_pcie_rp *pp)
 	pp->cfg0_size = resource_size(res);
 	pp->cfg0_base = res->start;
 
-	pp->va_cfg0_base = devm_pci_remap_cfg_resource(dev, res);
-	if (IS_ERR(pp->va_cfg0_base))
-		return PTR_ERR(pp->va_cfg0_base);
+	if (pp->ecam_enabled) {
+		ret = dw_pcie_create_ecam_window(pp, res);
+		if (ret)
+			return ret;
+
+		pp->bridge->ops = (struct pci_ops *)&pci_generic_ecam_ops.pci_ops;
+		pp->bridge->sysdata = pp->cfg;
+		pp->cfg->priv = pp;
+	} else {
+		pp->va_cfg0_base = devm_pci_remap_cfg_resource(dev, res);
+		if (IS_ERR(pp->va_cfg0_base))
+			return PTR_ERR(pp->va_cfg0_base);
+
+		/* Set default bus ops */
+		pp->bridge->ops = &dw_pcie_ops;
+		pp->bridge->child_ops = &dw_child_pcie_ops;
+		pp->bridge->sysdata = pp;
+	}
+
+	ret = dw_pcie_get_resources(pci);
+	if (ret) {
+		if (pp->cfg)
+			pci_ecam_free(pp->cfg);
+		return ret;
+	}
 
 	/* Get the I/O range from DT */
 	win = resource_list_first_type(&pp->bridge->windows, IORESOURCE_IO);
@@ -476,14 +555,10 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
 	if (ret)
 		return ret;
 
-	/* Set default bus ops */
-	bridge->ops = &dw_pcie_ops;
-	bridge->child_ops = &dw_child_pcie_ops;
-
 	if (pp->ops->init) {
 		ret = pp->ops->init(pp);
 		if (ret)
-			return ret;
+			goto err_free_ecam;
 	}
 
 	if (pci_msi_enabled()) {
@@ -525,6 +600,14 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
 	if (ret)
 		goto err_free_msi;
 
+	if (pp->ecam_enabled) {
+		ret = dw_pcie_config_ecam_iatu(pp);
+		if (ret) {
+			dev_err(dev, "Failed to configure iATU in ECAM mode\n");
+			goto err_free_msi;
+		}
+	}
+
 	/*
 	 * Allocate the resource for MSG TLP before programming the iATU
 	 * outbound window in dw_pcie_setup_rc(). Since the allocation depends
@@ -560,8 +643,6 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
 		/* Ignore errors, the link may come up later */
 		dw_pcie_wait_for_link(pci);
 
-	bridge->sysdata = pp;
-
 	ret = pci_host_probe(bridge);
 	if (ret)
 		goto err_stop_link;
@@ -587,6 +668,10 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp)
 	if (pp->ops->deinit)
 		pp->ops->deinit(pp);
 
+err_free_ecam:
+	if (pp->cfg)
+		pci_ecam_free(pp->cfg);
+
 	return ret;
 }
 EXPORT_SYMBOL_GPL(dw_pcie_host_init);
@@ -609,6 +694,9 @@ void dw_pcie_host_deinit(struct dw_pcie_rp *pp)
 
 	if (pp->ops->deinit)
 		pp->ops->deinit(pp);
+
+	if (pp->cfg)
+		pci_ecam_free(pp->cfg);
 }
 EXPORT_SYMBOL_GPL(dw_pcie_host_deinit);
 
diff --git a/drivers/pci/controller/dwc/pcie-designware.c b/drivers/pci/controller/dwc/pcie-designware.c
index 93da8a26c9313dfdd6b269a90bbfb017aab2abe7..ee8caae1edbd44c10e6986430a6932c10f20a9eb 100644
--- a/drivers/pci/controller/dwc/pcie-designware.c
+++ b/drivers/pci/controller/dwc/pcie-designware.c
@@ -575,7 +575,7 @@ int dw_pcie_prog_outbound_atu(struct dw_pcie *pci,
 		val = dw_pcie_enable_ecrc(val);
 	dw_pcie_writel_atu_ob(pci, atu->index, PCIE_ATU_REGION_CTRL1, val);
 
-	val = PCIE_ATU_ENABLE;
+	val = PCIE_ATU_ENABLE | atu->ctrl2;
 	if (atu->type == PCIE_ATU_TYPE_MSG) {
 		/* The data-less messages only for now */
 		val |= PCIE_ATU_INHIBIT_PAYLOAD | atu->code;
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 9eb3c4c762ddca7d6faff3a98a54b37d7cd9f11b..779868e8fa8fd78e5f35cd0fa2575f52cc07c335 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -20,6 +20,7 @@
 #include <linux/irq.h>
 #include <linux/msi.h>
 #include <linux/pci.h>
+#include <linux/pci-ecam.h>
 #include <linux/reset.h>
 
 #include <linux/pci-epc.h>
@@ -168,6 +169,7 @@
 #define PCIE_ATU_REGION_CTRL2		0x004
 #define PCIE_ATU_ENABLE			BIT(31)
 #define PCIE_ATU_BAR_MODE_ENABLE	BIT(30)
+#define PCIE_ATU_CFG_SHIFT_MODE_ENABLE	BIT(28)
 #define PCIE_ATU_INHIBIT_PAYLOAD	BIT(22)
 #define PCIE_ATU_FUNC_NUM_MATCH_EN      BIT(19)
 #define PCIE_ATU_LOWER_BASE		0x008
@@ -386,6 +388,7 @@ struct dw_pcie_ob_atu_cfg {
 	u8 func_no;
 	u8 code;
 	u8 routing;
+	u32 ctrl2;
 	u64 parent_bus_addr;
 	u64 pci_addr;
 	u64 size;
@@ -424,6 +427,8 @@ struct dw_pcie_rp {
 	struct resource		*msg_res;
 	bool			use_linkup_irq;
 	struct pci_eq_presets	presets;
+	struct pci_config_window *cfg;
+	bool			ecam_enabled;
 };
 
 struct dw_pcie_ep_ops {

-- 
2.48.1

[PATCH v10 3/4] PCI: qcom: Prepare for the DWC ECAM enablement

[Manivannan Sadhasivam]

From: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>

To support the DWC ECAM mechanism, prepare the driver by performing below
configurations:

  1. Since the ELBI region will be covered by the ECAM 'config' space,
     override the 'elbi_base' with the address derived from 'dbi_base' and
     the offset from PARF_SLV_DBI_ELBI register.

  2. Block the transactions from the host bridge to devices other than Root
     Port on the root bus to return all F's. This is required when the 'CFG
     Shift Feature' of iATU is enabled.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
[mani: code split, reworded subject/description and comments]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
---
 drivers/pci/controller/dwc/pcie-qcom.c | 68 ++++++++++++++++++++++++++++++++++
 1 file changed, 68 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c
index c48a20602d7fa4c50056ccf6502d3b5bf0a8287f..e6d2a6b0c087151781ddaf6bf7612f87e2445d17 100644
--- a/drivers/pci/controller/dwc/pcie-qcom.c
+++ b/drivers/pci/controller/dwc/pcie-qcom.c
@@ -55,6 +55,7 @@
 #define PARF_AXI_MSTR_WR_ADDR_HALT_V2		0x1a8
 #define PARF_Q2A_FLUSH				0x1ac
 #define PARF_LTSSM				0x1b0
+#define PARF_SLV_DBI_ELBI			0x1b4
 #define PARF_INT_ALL_STATUS			0x224
 #define PARF_INT_ALL_CLEAR			0x228
 #define PARF_INT_ALL_MASK			0x22c
@@ -64,6 +65,16 @@
 #define PARF_DBI_BASE_ADDR_V2_HI		0x354
 #define PARF_SLV_ADDR_SPACE_SIZE_V2		0x358
 #define PARF_SLV_ADDR_SPACE_SIZE_V2_HI		0x35c
+#define PARF_BLOCK_SLV_AXI_WR_BASE		0x360
+#define PARF_BLOCK_SLV_AXI_WR_BASE_HI		0x364
+#define PARF_BLOCK_SLV_AXI_WR_LIMIT		0x368
+#define PARF_BLOCK_SLV_AXI_WR_LIMIT_HI		0x36c
+#define PARF_BLOCK_SLV_AXI_RD_BASE		0x370
+#define PARF_BLOCK_SLV_AXI_RD_BASE_HI		0x374
+#define PARF_BLOCK_SLV_AXI_RD_LIMIT		0x378
+#define PARF_BLOCK_SLV_AXI_RD_LIMIT_HI		0x37c
+#define PARF_ECAM_BASE				0x380
+#define PARF_ECAM_BASE_HI			0x384
 #define PARF_NO_SNOOP_OVERRIDE			0x3d4
 #define PARF_ATU_BASE_ADDR			0x634
 #define PARF_ATU_BASE_ADDR_HI			0x638
@@ -87,6 +98,7 @@
 
 /* PARF_SYS_CTRL register fields */
 #define MAC_PHY_POWERDOWN_IN_P2_D_MUX_EN	BIT(29)
+#define PCIE_ECAM_BLOCKER_EN			BIT(26)
 #define MST_WAKEUP_EN				BIT(13)
 #define SLV_WAKEUP_EN				BIT(12)
 #define MSTR_ACLK_CGC_DIS			BIT(10)
@@ -134,6 +146,9 @@
 /* PARF_LTSSM register fields */
 #define LTSSM_EN				BIT(8)
 
+/* PARF_SLV_DBI_ELBI */
+#define SLV_DBI_ELBI_ADDR_BASE			GENMASK(11, 0)
+
 /* PARF_INT_ALL_{STATUS/CLEAR/MASK} register fields */
 #define PARF_INT_ALL_LINK_UP			BIT(13)
 #define PARF_INT_MSI_DEV_0_7			GENMASK(30, 23)
@@ -312,6 +327,47 @@ static void qcom_ep_reset_deassert(struct qcom_pcie *pcie)
 	qcom_perst_assert(pcie, false);
 }
 
+static void qcom_pci_config_ecam(struct dw_pcie_rp *pp)
+{
+	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
+	struct qcom_pcie *pcie = to_qcom_pcie(pci);
+	u64 addr, addr_end;
+	u32 val;
+
+	writel_relaxed(lower_32_bits(pci->dbi_phys_addr), pcie->parf + PARF_ECAM_BASE);
+	writel_relaxed(upper_32_bits(pci->dbi_phys_addr), pcie->parf + PARF_ECAM_BASE_HI);
+
+	/*
+	 * The only device on the root bus is a single Root Port. If we try to
+	 * access any devices other than Device/Function 00.0 on Bus 0, the TLP
+	 * will go outside of the controller to the PCI bus. But with CFG Shift
+	 * Feature (ECAM) enabled in iATU, there is no guarantee that the
+	 * response is going to be all F's. Hence, to make sure that the
+	 * requester gets all F's response for accesses other than the Root
+	 * Port, configure iATU to block the transactions starting from
+	 * function 1 of the root bus to the end of the root bus (i.e., from
+	 * dbi_base + 4KB to dbi_base + 1MB).
+	 */
+	addr = pci->dbi_phys_addr + SZ_4K;
+	writel_relaxed(lower_32_bits(addr), pcie->parf + PARF_BLOCK_SLV_AXI_WR_BASE);
+	writel_relaxed(upper_32_bits(addr), pcie->parf + PARF_BLOCK_SLV_AXI_WR_BASE_HI);
+
+	writel_relaxed(lower_32_bits(addr), pcie->parf + PARF_BLOCK_SLV_AXI_RD_BASE);
+	writel_relaxed(upper_32_bits(addr), pcie->parf + PARF_BLOCK_SLV_AXI_RD_BASE_HI);
+
+	addr_end = pci->dbi_phys_addr + SZ_1M - 1;
+
+	writel_relaxed(lower_32_bits(addr_end), pcie->parf + PARF_BLOCK_SLV_AXI_WR_LIMIT);
+	writel_relaxed(upper_32_bits(addr_end), pcie->parf + PARF_BLOCK_SLV_AXI_WR_LIMIT_HI);
+
+	writel_relaxed(lower_32_bits(addr_end), pcie->parf + PARF_BLOCK_SLV_AXI_RD_LIMIT);
+	writel_relaxed(upper_32_bits(addr_end), pcie->parf + PARF_BLOCK_SLV_AXI_RD_LIMIT_HI);
+
+	val = readl_relaxed(pcie->parf + PARF_SYS_CTRL);
+	val |= PCIE_ECAM_BLOCKER_EN;
+	writel_relaxed(val, pcie->parf + PARF_SYS_CTRL);
+}
+
 static int qcom_pcie_start_link(struct dw_pcie *pci)
 {
 	struct qcom_pcie *pcie = to_qcom_pcie(pci);
@@ -1284,6 +1340,7 @@ static int qcom_pcie_host_init(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
 	struct qcom_pcie *pcie = to_qcom_pcie(pci);
+	u16 offset;
 	int ret;
 
 	qcom_ep_reset_assert(pcie);
@@ -1292,6 +1349,17 @@ static int qcom_pcie_host_init(struct dw_pcie_rp *pp)
 	if (ret)
 		return ret;
 
+	if (pp->ecam_enabled) {
+		/*
+		 * Override ELBI when ECAM is enabled, as when ECAM is enabled,
+		 * ELBI moves under the 'config' space.
+		 */
+		offset = FIELD_GET(SLV_DBI_ELBI_ADDR_BASE, readl(pcie->parf + PARF_SLV_DBI_ELBI));
+		pci->elbi_base = pci->dbi_base + offset;
+
+		qcom_pci_config_ecam(pp);
+	}
+
 	ret = qcom_pcie_phy_power_on(pcie);
 	if (ret)
 		goto err_deinit;

-- 
2.48.1

[PATCH v10 4/4] PCI: dwc: Support ECAM mechanism by enabling iATU 'CFG Shift Feature'

[Manivannan Sadhasivam]

From: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>

Designware databook r5.20a, sec 3.10.10.3 documents the 'CFG Shift Feature'
of the internal Address Translation Unit (iATU). When this feature is
enabled, it shifts/maps the BDF contained in the bits [27:12] of the target
address in MEM TLP to become BDF of the CFG TLP. This essentially
implements the Enhanced Configuration Address Mapping (ECAM) mechanism as
defined in PCIe r6.0, sec 7.2.2.

Currently, the driver is not making use of this CFG shift feature, thereby
creating the iATU outbound map for each config access to the devices,
causing latency and wasting CPU cycles.

So to avoid this, configure the controller to enable CFG shift feature by
enabling the 'CFG Shift' bit of the 'iATU Control 2 Register'.

As a result of enabling CFG shift (ECAM), there is longer a need to map the
DBI register space separately as the DBI region falls under the 'config'
space used for ECAM (as DBI is used to access the Root Port).

For enabling ECAM using CFG shift, the platform has to satisfy following
requirements:

  1. Size of the 'config' memory space to be used as ECAM memory should be
     able to accommodate the number of buses defined in the 'bus-range'
     property of the host bridge DT node.

  2. The 'config' memory space should be 256 MiB aligned. This requirement
     comes from PCIe r6.0, sec 7.2.2, which says the base address of ECAM
     memory should be aligned to a 2^(n+20) byte address boundary. For the
     DWC cores, n is 8, so this results in 2^28 byte alignment requirement.

It should be noted that some DWC vendor glue drivers like pcie-al may use
their own ECAM mechanism. For those controllers, set
'dw_pcie_rp::native_ecam' flag and skip enabling the CFG Shift feature in
the DWC core.

Signed-off-by: Krishna Chaitanya Chundru <krishna.chundru@oss.qualcomm.com>
[mani: code split, reworded subject/description, comment, native_ecam flag]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
---
 drivers/pci/controller/dwc/pcie-al.c              |  1 +
 drivers/pci/controller/dwc/pcie-designware-host.c | 32 +++++++++++++++++++++++
 drivers/pci/controller/dwc/pcie-designware.h      |  1 +
 3 files changed, 34 insertions(+)

diff --git a/drivers/pci/controller/dwc/pcie-al.c b/drivers/pci/controller/dwc/pcie-al.c
index 643115f74092d1c9319e9738db6e94b2752d30c4..345c281c74fefd2113233ef5461f96834b3765de 100644
--- a/drivers/pci/controller/dwc/pcie-al.c
+++ b/drivers/pci/controller/dwc/pcie-al.c
@@ -352,6 +352,7 @@ static int al_pcie_probe(struct platform_device *pdev)
 		return -ENOENT;
 	}
 	al_pcie->ecam_size = resource_size(ecam_res);
+	pci->pp.native_ecam = true;
 
 	controller_res = platform_get_resource_byname(pdev, IORESOURCE_MEM,
 						      "controller");
diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c
index 94e0fe11a0b062d0f14e09fe586e20bde46a4266..20c9333bcb1c4812e2fd96047a49944574df1e6f 100644
--- a/drivers/pci/controller/dwc/pcie-designware-host.c
+++ b/drivers/pci/controller/dwc/pcie-designware-host.c
@@ -8,6 +8,7 @@
  * Author: Jingoo Han <jg1.han@samsung.com>
  */
 
+#include <linux/align.h>
 #include <linux/iopoll.h>
 #include <linux/irqchip/chained_irq.h>
 #include <linux/irqchip/irq-msi-lib.h>
@@ -32,6 +33,8 @@ static struct pci_ops dw_child_pcie_ops;
 				     MSI_FLAG_PCI_MSIX			| \
 				     MSI_GENERIC_FLAGS_MASK)
 
+#define IS_256MB_ALIGNED(x) IS_ALIGNED(x, SZ_256M)
+
 static const struct msi_parent_ops dw_pcie_msi_parent_ops = {
 	.required_flags		= DW_PCIE_MSI_FLAGS_REQUIRED,
 	.supported_flags	= DW_PCIE_MSI_FLAGS_SUPPORTED,
@@ -474,6 +477,34 @@ static int dw_pcie_create_ecam_window(struct dw_pcie_rp *pp, struct resource *re
 	return 0;
 }
 
+static bool dw_pcie_ecam_enabled(struct dw_pcie_rp *pp, struct resource *config_res)
+{
+	struct resource *bus_range;
+	u64 nr_buses;
+
+	/* Vendor glue drivers may implement their own ECAM mechanism */
+	if (pp->native_ecam)
+		return false;
+
+	/*
+	 * PCIe spec r6.0, sec 7.2.2 mandates the base address used for ECAM to
+	 * be aligned on a 2^(n+20) byte boundary, where n is the number of bits
+	 * used for representing 'bus' in BDF. Since the DWC cores always use 8
+	 * bits for representing 'bus', the base address has to be aligned to
+	 * 2^28 byte boundary, which is 256 MiB.
+	 */
+	if (!IS_256MB_ALIGNED(config_res->start))
+		return false;
+
+	bus_range = resource_list_first_type(&pp->bridge->windows, IORESOURCE_BUS)->res;
+	if (!bus_range)
+		return false;
+
+	nr_buses = resource_size(config_res) >> PCIE_ECAM_BUS_SHIFT;
+
+	return nr_buses >= resource_size(bus_range);
+}
+
 static int dw_pcie_host_get_resources(struct dw_pcie_rp *pp)
 {
 	struct dw_pcie *pci = to_dw_pcie_from_pp(pp);
@@ -492,6 +523,7 @@ static int dw_pcie_host_get_resources(struct dw_pcie_rp *pp)
 	pp->cfg0_size = resource_size(res);
 	pp->cfg0_base = res->start;
 
+	pp->ecam_enabled = dw_pcie_ecam_enabled(pp, res);
 	if (pp->ecam_enabled) {
 		ret = dw_pcie_create_ecam_window(pp, res);
 		if (ret)
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 779868e8fa8fd78e5f35cd0fa2575f52cc07c335..625320565360c0134ee9345bcc2e54a6ce83326a 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -429,6 +429,7 @@ struct dw_pcie_rp {
 	struct pci_eq_presets	presets;
 	struct pci_config_window *cfg;
 	bool			ecam_enabled;
+	bool			native_ecam;
 };
 
 struct dw_pcie_ep_ops {

-- 
2.48.1

Re: [PATCH v10 0/4] PCI: dwc: Add ECAM support with iATU configuration

[Manivannan Sadhasivam]

On Tue, 23 Sep 2025 16:56:50 +0530, Manivannan Sadhasivam wrote:
> The current implementation requires iATU for every configuration
> space access which increases latency & cpu utilization.
> 
> Designware databook 5.20a, section 3.10.10.3 says about CFG Shift Feature,
> which shifts/maps the BDF (bits [31:16] of the third header DWORD, which
> would be matched against the Base and Limit addresses) of the incoming
> CfgRd0/CfgWr0 down to bits[27:12]of the translated address.
> 
> [...]

Applied to pci/controller/qcom, thanks!

[1/4] PCI: dwc: Add support for ELBI resource mapping
      commit: c96992a24beca0768c1c42ad25d6a466e17ec70f
[2/4] PCI: dwc: Prepare the driver for enabling ECAM mechanism using iATU 'CFG Shift Feature'
      commit: f6fd357f7afbeb34a633e5688a23b9d7eb49d558
[3/4] PCI: qcom: Prepare for the DWC ECAM enablement
      commit: 4660e50cf81800f82eeecf743ad1e3e97ab72190
[4/4] PCI: dwc: Support ECAM mechanism by enabling iATU 'CFG Shift Feature'
      commit: 0da48c5b2fa731b21bc523c82d927399a1e508b0

Best regards,
-- 
Manivannan Sadhasivam <mani@kernel.org>