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PCI: brcmstb: Fix disabling L0s capability

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caab002d50 ("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.
b478e162f2 ("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: caab002d50 ("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
This commit is contained in:
Jim Quinlan
2025-10-03 13:04:36 -04:00
committed by Bjorn Helgaas
parent 3a86608788
commit 9583f9d229
1 changed files with 3 additions and 7 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
drivers/pci/controller/pcie-brcmstb.c
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@@ -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 */