[PATCH AUTOSEL 4.19 47/47] PCI/ASPM: Allow re-enabling Clock PM

From: Sasha Levin
Date: Sat Apr 18 2020 - 10:49:37 EST


From: Heiner Kallweit <hkallweit1@xxxxxxxxx>

[ Upstream commit 35efea32b26f9aacc99bf07e0d2cdfba2028b099 ]

Previously Clock PM could not be re-enabled after being disabled by
pci_disable_link_state() because clkpm_capable was reset. Change this by
adding a clkpm_disable field similar to aspm_disable.

Link: https://lore.kernel.org/r/4e8a66db-7d53-4a66-c26c-f0037ffaa705@xxxxxxxxx
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/pci/pcie/aspm.c | 18 +++++++++++-------
1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 1117b25fbe0bb..2948f86d88969 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -67,6 +67,7 @@ struct pcie_link_state {
u32 clkpm_capable:1; /* Clock PM capable? */
u32 clkpm_enabled:1; /* Current Clock PM state */
u32 clkpm_default:1; /* Default Clock PM state by BIOS */
+ u32 clkpm_disable:1; /* Clock PM disabled */

/* Exit latencies */
struct aspm_latency latency_up; /* Upstream direction exit latency */
@@ -164,8 +165,11 @@ static void pcie_set_clkpm_nocheck(struct pcie_link_state *link, int enable)

static void pcie_set_clkpm(struct pcie_link_state *link, int enable)
{
- /* Don't enable Clock PM if the link is not Clock PM capable */
- if (!link->clkpm_capable)
+ /*
+ * Don't enable Clock PM if the link is not Clock PM capable
+ * or Clock PM is disabled
+ */
+ if (!link->clkpm_capable || link->clkpm_disable)
enable = 0;
/* Need nothing if the specified equals to current state */
if (link->clkpm_enabled == enable)
@@ -195,7 +199,8 @@ static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
}
link->clkpm_enabled = enabled;
link->clkpm_default = enabled;
- link->clkpm_capable = (blacklist) ? 0 : capable;
+ link->clkpm_capable = capable;
+ link->clkpm_disable = blacklist ? 1 : 0;
}

static bool pcie_retrain_link(struct pcie_link_state *link)
@@ -1106,10 +1111,9 @@ static void __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
link->aspm_disable |= ASPM_STATE_L1;
pcie_config_aspm_link(link, policy_to_aspm_state(link));

- if (state & PCIE_LINK_STATE_CLKPM) {
- link->clkpm_capable = 0;
- pcie_set_clkpm(link, 0);
- }
+ if (state & PCIE_LINK_STATE_CLKPM)
+ link->clkpm_disable = 1;
+ pcie_set_clkpm(link, policy_to_clkpm_state(link));
mutex_unlock(&aspm_lock);
if (sem)
up_read(&pci_bus_sem);
--
2.20.1