[PATCH v4 2/4] PCI/ASPM: allow to re-enable Clock PM

Heiner Kallweit
2019-08-24T15:42:22Z

So far Clock PM can't be re-enabled once it has been disabled with
a call to pci_disable_link_state(). Reason is that clkpm_capable
is reset. Change this by adding a clkpm_disable field similar to
aspm_disable.

Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
---
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 1c1b9b7d6..149b876c9 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -65,6 +65,7 @@ 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 */
@@ -162,8 +163,11 @@ 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)
@@ -193,7 +197,8 @@ 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)
@@ -1107,10 +1112,9 @@ static int __pci_disable_link_state(struct pci_dev *pdev, int state, bool sem)
link->aspm_disable |= ASPM_STATE_L1_2_PCIPM;
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);
--
2.23.0