linux-kernel - [PATCH] PCI: dwc: Remove duplicate dw_pcie_ep_hide_ext

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Message-Id: <20251224-remove_dw_pcie_ep_hide_ext_capability-v1-1-4302c9cdc316@oss.qualcomm.com>
Date: Wed, 24 Dec 2025 02:10:46 -0800
From: Qiang Yu <qiang.yu@....qualcomm.com>
To: Jingoo Han <jingoohan1@...il.com>, Manivannan Sadhasivam <mani@...nel.org>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Krzysztof Wilczyński <kwilczynski@...nel.org>,
        Rob Herring <robh@...nel.org>, Bjorn Helgaas <bhelgaas@...gle.com>,
        Heiko Stuebner <heiko@...ech.de>
Cc: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-rockchip@...ts.infradead.org, Niklas Cassel <cassel@...nel.org>,
        Qiang Yu <qiang.yu@....qualcomm.com>
Subject: [PATCH] PCI: dwc: Remove duplicate
 dw_pcie_ep_hide_ext_capability() function

Remove dw_pcie_ep_hide_ext_capability() and replace its usage with
dw_pcie_remove_ext_capability(). Both functions serve the same purpose
of hiding PCIe extended capabilities, but dw_pcie_remove_ext_capability()
provides a cleaner API that doesn't require the caller to specify the
previous capability ID.

Compile-tested only. Runtime testing on RK3588 hardware would be
appreciated.

Suggested-by: Niklas Cassel <cassel@...nel.org>
Signed-off-by: Qiang Yu <qiang.yu@....qualcomm.com>
---
 drivers/pci/controller/dwc/pcie-designware-ep.c | 39 -------------------------
 drivers/pci/controller/dwc/pcie-designware.h    |  7 -----
 drivers/pci/controller/dwc/pcie-dw-rockchip.c   |  4 +--
 3 files changed, 1 insertion(+), 49 deletions(-)

diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c
index 1195d401df19eafbab2fb267f5cda3c24ecdfbd1..cfd59899c7b85fd0dddc9c6ce6b9c9fed84ad7a3 100644
--- a/drivers/pci/controller/dwc/pcie-designware-ep.c
+++ b/drivers/pci/controller/dwc/pcie-designware-ep.c
@@ -75,45 +75,6 @@ static u8 dw_pcie_ep_find_capability(struct dw_pcie_ep *ep, u8 func_no, u8 cap)
 				 cap, NULL, ep, func_no);
 }
 
-/**
- * dw_pcie_ep_hide_ext_capability - Hide a capability from the linked list
- * @pci: DWC PCI device
- * @prev_cap: Capability preceding the capability that should be hidden
- * @cap: Capability that should be hidden
- *
- * Return: 0 if success, errno otherwise.
- */
-int dw_pcie_ep_hide_ext_capability(struct dw_pcie *pci, u8 prev_cap, u8 cap)
-{
-	u16 prev_cap_offset, cap_offset;
-	u32 prev_cap_header, cap_header;
-
-	prev_cap_offset = dw_pcie_find_ext_capability(pci, prev_cap);
-	if (!prev_cap_offset)
-		return -EINVAL;
-
-	prev_cap_header = dw_pcie_readl_dbi(pci, prev_cap_offset);
-	cap_offset = PCI_EXT_CAP_NEXT(prev_cap_header);
-	cap_header = dw_pcie_readl_dbi(pci, cap_offset);
-
-	/* cap must immediately follow prev_cap. */
-	if (PCI_EXT_CAP_ID(cap_header) != cap)
-		return -EINVAL;
-
-	/* Clear next ptr. */
-	prev_cap_header &= ~GENMASK(31, 20);
-
-	/* Set next ptr to next ptr of cap. */
-	prev_cap_header |= cap_header & GENMASK(31, 20);
-
-	dw_pcie_dbi_ro_wr_en(pci);
-	dw_pcie_writel_dbi(pci, prev_cap_offset, prev_cap_header);
-	dw_pcie_dbi_ro_wr_dis(pci);
-
-	return 0;
-}
-EXPORT_SYMBOL_GPL(dw_pcie_ep_hide_ext_capability);
-
 static int dw_pcie_ep_write_header(struct pci_epc *epc, u8 func_no, u8 vfunc_no,
 				   struct pci_epf_header *hdr)
 {
diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h
index 3a81d46e60b00f7cb92d9634eba6708244bce976..c5fff03073ea3945a5c38b1626838c6a67d21c57 100644
--- a/drivers/pci/controller/dwc/pcie-designware.h
+++ b/drivers/pci/controller/dwc/pcie-designware.h
@@ -909,7 +909,6 @@ int dw_pcie_ep_raise_msix_irq(struct dw_pcie_ep *ep, u8 func_no,
 int dw_pcie_ep_raise_msix_irq_doorbell(struct dw_pcie_ep *ep, u8 func_no,
 				       u16 interrupt_num);
 void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar);
-int dw_pcie_ep_hide_ext_capability(struct dw_pcie *pci, u8 prev_cap, u8 cap);
 struct dw_pcie_ep_func *
 dw_pcie_ep_get_func_from_ep(struct dw_pcie_ep *ep, u8 func_no);
 #else
@@ -967,12 +966,6 @@ static inline void dw_pcie_ep_reset_bar(struct dw_pcie *pci, enum pci_barno bar)
 {
 }
 
-static inline int dw_pcie_ep_hide_ext_capability(struct dw_pcie *pci,
-						 u8 prev_cap, u8 cap)
-{
-	return 0;
-}
-
 static inline struct dw_pcie_ep_func *
 dw_pcie_ep_get_func_from_ep(struct dw_pcie_ep *ep, u8 func_no)
 {
diff --git a/drivers/pci/controller/dwc/pcie-dw-rockchip.c b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
index 352f513ebf0363ff0ec79fdd8d8b245eeb28474c..77c4e6a4ddead91fe12eb6c727e77350207ef5fa 100644
--- a/drivers/pci/controller/dwc/pcie-dw-rockchip.c
+++ b/drivers/pci/controller/dwc/pcie-dw-rockchip.c
@@ -347,9 +347,7 @@ static void rockchip_pcie_ep_hide_broken_ats_cap_rk3588(struct dw_pcie_ep *ep)
 	if (!of_device_is_compatible(dev->of_node, "rockchip,rk3588-pcie-ep"))
 		return;
 
-	if (dw_pcie_ep_hide_ext_capability(pci, PCI_EXT_CAP_ID_SECPCI,
-					   PCI_EXT_CAP_ID_ATS))
-		dev_err(dev, "failed to hide ATS capability\n");
+	dw_pcie_remove_ext_capability(pci, PCI_EXT_CAP_ID_ATS);
 }
 
 static void rockchip_pcie_ep_init(struct dw_pcie_ep *ep)

---
base-commit: 37781eb814e16c75abb78dec2f9412d2e4d88298
change-id: 20251224-remove_dw_pcie_ep_hide_ext_capability-3dba1507a331

Best regards,
-- 
Qiang Yu <qiang.yu@....qualcomm.com>