The patch below does not apply to the 5.15-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-5.15.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 '2026010521-confetti-french-f994@gregkh' --subject-prefix 'PATCH 5.15.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 */