2021-11-06 21:37:33

by Saheed O. Bolarinwa

Subject: [RFC PATCH v2 2/3] PCI/ASPM: Remove struct pcie_link_state.clkpm_capable

The clkpm_capable member of the struct pcie_link_state indicates
if the device is Clock PM capable. This can be calculated when
it is needed, because it comes from Link Capabilities, a read-only
register.

- remove clkpm_capable from struct pcie_link_state
- move the calculation of clkpm_capable into
pcie_is_clkpm_capable()
- replace references to clkpm_capable with a call to
pcie_is_clkpm_capable()

Signed-off-by: Saheed O. Bolarinwa <[email protected]>
---
drivers/pci/pcie/aspm.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index e5202cc16ef0..c1f8f10b7a4c 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -61,7 +61,6 @@ struct pcie_link_state {
u32 aspm_disable:7; /* Disabled ASPM state */

/* Clock PM 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 */
@@ -105,6 +104,20 @@ static const char *policy_str[] = {

#define LINK_RETRAIN_TIMEOUT HZ

+static int pcie_clkpm_capable(struct pci_dev *pdev)
+{
+ u32 cap;
+ struct pci_dev *child;
+ struct pci_bus *linkbus = pdev->subordinate;
+
+ list_for_each_entry(child, &linkbus->devices, bus_list) {
+ pcie_capability_read_dword(child, PCI_EXP_LNKCAP, &cap);
+ if (!(cap & PCI_EXP_LNKCAP_CLKPM))
+ return 0;
+ }
+ return 1;
+}
+
static int policy_to_aspm_state(struct pcie_link_state *link)
{
switch (aspm_policy) {
@@ -149,7 +162,7 @@ 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
* or Clock PM is disabled
*/
- if (!link->clkpm_capable || link->clkpm_disable)
+ if (!pcie_clkpm_capable(link->pdev) || link->clkpm_disable)
enable = 0;
/* Need nothing if the specified equals to current state */
if (link->clkpm_enabled == enable)
@@ -166,7 +179,7 @@ static void pcie_set_clkpm(struct pcie_link_state *link, int enable)

static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
{
- int capable = 1, enabled = 1;
+ int enabled = 1;
u32 reg32;
u16 reg16;
struct pci_dev *child;
@@ -176,7 +189,6 @@ static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
list_for_each_entry(child, &linkbus->devices, bus_list) {
pcie_capability_read_dword(child, PCI_EXP_LNKCAP, &reg32);
if (!(reg32 & PCI_EXP_LNKCAP_CLKPM)) {
- capable = 0;
enabled = 0;
break;
}
@@ -186,7 +198,6 @@ static void pcie_clkpm_cap_init(struct pcie_link_state *link, int blacklist)
}
link->clkpm_enabled = enabled;
link->clkpm_default = enabled;
- link->clkpm_capable = capable;
link->clkpm_disable = blacklist ? 1 : 0;
}

@@ -1327,7 +1338,7 @@ static umode_t aspm_ctrl_attrs_are_visible(struct kobject *kobj,
return 0;

if (n == 0)
- return link->clkpm_capable ? a->mode : 0;
+ return pcie_clkpm_capable(link->pdev) ? a->mode : 0;

return link->aspm_capable & aspm_state_map[n - 1] ? a->mode : 0;
}
--
2.20.1