FAILED: patch "[PATCH] PCI: brcmstb: Fix disabling L0s capability" failed to apply to 6.6-stable tree

FAILED: patch "[PATCH] PCI: brcmstb: Fix disabling L0s capability" failed to apply to 6.6-stable tree

[gregkh]

The patch below does not apply to the 6.6-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.6.y
git checkout FETCH_HEAD
git cherry-pick -x 9583f9d22991d2cfb5cc59a2552040c4ae98d998
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<stable@vger.kernel.org>' --in-reply-to '2026010520-wreckage-quantum-ba65@gregkh' --subject-prefix 'PATCH 6.6.y' HEAD^..

Possible dependencies:



thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 9583f9d22991d2cfb5cc59a2552040c4ae98d998 Mon Sep 17 00:00:00 2001
From: Jim Quinlan <james.quinlan@broadcom.com>
Date: Fri, 3 Oct 2025 13:04:36 -0400
Subject: [PATCH] PCI: brcmstb: Fix disabling L0s capability

caab002d5069 ("PCI: brcmstb: Disable L0s component of ASPM if requested")
set PCI_EXP_LNKCAP_ASPM_L1 and (optionally) PCI_EXP_LNKCAP_ASPM_L0S in
PCI_EXP_LNKCAP (aka PCIE_RC_CFG_PRIV1_LINK_CAPABILITY in brcmstb).

But instead of using PCI_EXP_LNKCAP_ASPM_L1 and PCI_EXP_LNKCAP_ASPM_L0S
directly, it used PCIE_LINK_STATE_L1 and PCIE_LINK_STATE_L0S, which are
Linux-created values that only coincidentally matched the PCIe spec.
b478e162f227 ("PCI/ASPM: Consolidate link state defines") later changed
them so they no longer matched the PCIe spec, so the bits ended up in the
wrong place in PCI_EXP_LNKCAP.

Use PCI_EXP_LNKCAP_ASPM_L0S to clear L0s support when there's an
'aspm-no-l0s' property.  Rely on brcmstb hardware to advertise L0s and/or
L1 support otherwise.

Fixes: caab002d5069 ("PCI: brcmstb: Disable L0s component of ASPM if requested")
Reported-by: Bjorn Helgaas <bhelgaas@google.com>
Closes: https://lore.kernel.org/linux-pci/20250925194424.GA2197200@bhelgaas
Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
[mani: reworded subject and description, added closes tag and CCed stable]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251003170436.1446030-1-james.quinlan@broadcom.com

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 9afbd02ded35..7e9b2f6a604a 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -48,7 +48,6 @@
 
 #define PCIE_RC_CFG_PRIV1_LINK_CAPABILITY			0x04dc
 #define  PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_MAX_LINK_WIDTH_MASK	0x1f0
-#define  PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_ASPM_SUPPORT_MASK	0xc00
 
 #define PCIE_RC_CFG_PRIV1_ROOT_CAP			0x4f8
 #define  PCIE_RC_CFG_PRIV1_ROOT_CAP_L1SS_MODE_MASK	0xf8
@@ -1075,7 +1074,7 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 	void __iomem *base = pcie->base;
 	struct pci_host_bridge *bridge;
 	struct resource_entry *entry;
-	u32 tmp, burst, aspm_support, num_lanes, num_lanes_cap;
+	u32 tmp, burst, num_lanes, num_lanes_cap;
 	u8 num_out_wins = 0;
 	int num_inbound_wins = 0;
 	int memc, ret;
@@ -1175,12 +1174,9 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 
 
 	/* Don't advertise L0s capability if 'aspm-no-l0s' */
-	aspm_support = PCIE_LINK_STATE_L1;
-	if (!of_property_read_bool(pcie->np, "aspm-no-l0s"))
-		aspm_support |= PCIE_LINK_STATE_L0S;
 	tmp = readl(base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
-	u32p_replace_bits(&tmp, aspm_support,
-		PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_ASPM_SUPPORT_MASK);
+	if (of_property_read_bool(pcie->np, "aspm-no-l0s"))
+		tmp &= ~PCI_EXP_LNKCAP_ASPM_L0S;
 	writel(tmp, base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
 
 	/* 'tmp' still holds the contents of PRIV1_LINK_CAPABILITY */

[PATCH 6.6.y] PCI: brcmstb: Fix disabling L0s capability

[Sasha Levin]

From: Jim Quinlan <james.quinlan@broadcom.com>

[ Upstream commit 9583f9d22991d2cfb5cc59a2552040c4ae98d998 ]

caab002d5069 ("PCI: brcmstb: Disable L0s component of ASPM if requested")
set PCI_EXP_LNKCAP_ASPM_L1 and (optionally) PCI_EXP_LNKCAP_ASPM_L0S in
PCI_EXP_LNKCAP (aka PCIE_RC_CFG_PRIV1_LINK_CAPABILITY in brcmstb).

But instead of using PCI_EXP_LNKCAP_ASPM_L1 and PCI_EXP_LNKCAP_ASPM_L0S
directly, it used PCIE_LINK_STATE_L1 and PCIE_LINK_STATE_L0S, which are
Linux-created values that only coincidentally matched the PCIe spec.
b478e162f227 ("PCI/ASPM: Consolidate link state defines") later changed
them so they no longer matched the PCIe spec, so the bits ended up in the
wrong place in PCI_EXP_LNKCAP.

Use PCI_EXP_LNKCAP_ASPM_L0S to clear L0s support when there's an
'aspm-no-l0s' property.  Rely on brcmstb hardware to advertise L0s and/or
L1 support otherwise.

Fixes: caab002d5069 ("PCI: brcmstb: Disable L0s component of ASPM if requested")
Reported-by: Bjorn Helgaas <bhelgaas@google.com>
Closes: https://lore.kernel.org/linux-pci/20250925194424.GA2197200@bhelgaas
Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com>
[mani: reworded subject and description, added closes tag and CCed stable]
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20251003170436.1446030-1-james.quinlan@broadcom.com
[ adapted context due to missing link width negotiation defines and variables ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/pci/controller/pcie-brcmstb.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
index 9bcf4c68058e..8850a15b0aec 100644
--- a/drivers/pci/controller/pcie-brcmstb.c
+++ b/drivers/pci/controller/pcie-brcmstb.c
@@ -46,7 +46,6 @@
 #define  PCIE_RC_CFG_PRIV1_ID_VAL3_CLASS_CODE_MASK	0xffffff
 
 #define PCIE_RC_CFG_PRIV1_LINK_CAPABILITY			0x04dc
-#define  PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_ASPM_SUPPORT_MASK	0xc00
 
 #define PCIE_RC_DL_MDIO_ADDR				0x1100
 #define PCIE_RC_DL_MDIO_WR_DATA				0x1104
@@ -867,7 +866,7 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 	void __iomem *base = pcie->base;
 	struct pci_host_bridge *bridge;
 	struct resource_entry *entry;
-	u32 tmp, burst, aspm_support;
+	u32 tmp, burst;
 	int num_out_wins = 0;
 	int ret, memc;
 
@@ -971,12 +970,9 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
 	writel(tmp, base + PCIE_MISC_RC_BAR3_CONFIG_LO);
 
 	/* Don't advertise L0s capability if 'aspm-no-l0s' */
-	aspm_support = PCIE_LINK_STATE_L1;
-	if (!of_property_read_bool(pcie->np, "aspm-no-l0s"))
-		aspm_support |= PCIE_LINK_STATE_L0S;
 	tmp = readl(base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
-	u32p_replace_bits(&tmp, aspm_support,
-		PCIE_RC_CFG_PRIV1_LINK_CAPABILITY_ASPM_SUPPORT_MASK);
+	if (of_property_read_bool(pcie->np, "aspm-no-l0s"))
+		tmp &= ~PCI_EXP_LNKCAP_ASPM_L0S;
 	writel(tmp, base + PCIE_RC_CFG_PRIV1_LINK_CAPABILITY);
 
 	/*
-- 
2.51.0