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Message-Id: <20211106175353.26248-7-refactormyself@gmail.com>
Date: Sat, 6 Nov 2021 18:53:53 +0100
From: "Saheed O. Bolarinwa" <refactormyself@...il.com>
To: helgaas@...nel.org
Cc: "Saheed O. Bolarinwa" <refactormyself@...il.com>,
linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [RFC PATCH v1 6/6] PCI/ASPM: Don't cache struct pcie_link_state->aspm_enabled
aspm_enabled in struct pcie_link_state usually holds the current
enabled states of the link. This value is set in two places:
1. pcie_aspm_cap_init(): if the passed in blacklist value holds true,
then `link->aspm_enabled = ASPM_STATE_ALL` otherwise values are
read from the register and link->aspm_enabled is calculated.
This calculation has been extracted into aspm_calc_enabled_states()
in an earlier patch in this series.
2. pcie_config_aspm_link(): when a valid state is calculated from the
value passed in. The result is later written into the register. The
calculated valid state is then store in struct
pcie_link_state->aspm_enabled.
The calculations in aspm_calc_enabled_states() reads and uses the
current state in the register. This can be called whenever
link->aspm_enabled is needed. We don't need to store the state.
For the case when blacklist value holds in pcie_aspm_cap_init(), this
value comes from pcie_aspm_init_link_state(). We can obtain this value
whenever link->aspm_enabled is needed and determine if the current
enabled states should be set to "ASPM_STATE_ALL". So also in this case
we don't need to store the enabled states, it can be obtained on the
fly.
- Remove aspm_enabled from struct pcie_link_state.
- Create a wrapper function arround aspm_calc_enabled_states().
- Replace references to aspm_enabled with a function call.
Signed-off-by: Saheed O. Bolarinwa <refactormyself@...il.com>
---
drivers/pci/pcie/aspm.c | 36 ++++++++++++++++++++++--------------
1 file changed, 22 insertions(+), 14 deletions(-)
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 05ca165380e1..dce0851c6ab5 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -54,7 +54,6 @@ struct pcie_link_state {
struct list_head sibling; /* node in link_list */
/* ASPM state */
- u32 aspm_enabled:7; /* Enabled ASPM state */
u32 aspm_capable:7; /* Capable ASPM state with latency */
u32 aspm_default:7; /* Default ASPM state by BIOS */
u32 aspm_disable:7; /* Disabled ASPM state */
@@ -676,6 +675,18 @@ static u32 aspm_calc_enabled_states(struct pcie_link_state *link,
return aspm_enabled;
}
+static u32 aspm_get_enabled_states(struct pcie_link_state *link)
+{
+ u32 up_l1ss_cap, dwn_l1ss_cap;
+
+ if (pcie_aspm_sanity_check(link->pdev))
+ return ASPM_STATE_ALL;
+
+ aspm_calc_both_l1ss_caps(link, &up_l1ss_cap, &dwn_l1ss_cap);
+
+ return aspm_calc_enabled_states(link, up_l1ss_cap, dwn_l1ss_cap);
+}
+
static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
{
struct pci_dev *child = link->downstream, *parent = link->pdev;
@@ -684,8 +695,7 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
struct pci_bus *linkbus = parent->subordinate;
if (blacklist) {
- /* Set enabled/disable so that we will disable ASPM later */
- link->aspm_enabled = ASPM_STATE_ALL;
+ /* Set disable so that we will disable ASPM later */
link->aspm_disable = ASPM_STATE_ALL;
return;
}
@@ -719,11 +729,9 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
/* Setup L1 substate */
aspm_calc_both_l1ss_caps(link, &parent_l1ss_cap, &child_l1ss_cap);
- link->aspm_enabled = aspm_calc_enabled_states(link, parent_l1ss_cap,
- child_l1ss_cap);
-
/* Save default state */
- link->aspm_default = link->aspm_enabled;
+ link->aspm_default = aspm_calc_enabled_states(link, parent_l1ss_cap,
+ child_l1ss_cap);
aspm_support = aspm_calc_init_linkcap(parent_lnkcap, child_lnkcap,
parent_l1ss_cap, child_l1ss_cap);
@@ -762,7 +770,7 @@ static void pcie_config_aspm_l1ss(struct pcie_link_state *link, u32 state)
u32 val, enable_req;
struct pci_dev *child = link->downstream, *parent = link->pdev;
- enable_req = (link->aspm_enabled ^ state) & state;
+ enable_req = (aspm_get_enabled_states(link) ^ state) & state;
/*
* Here are the rules specified in the PCIe spec for enabling L1SS:
@@ -821,6 +829,7 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
u32 upstream = 0, dwstream = 0;
struct pci_dev *child = link->downstream, *parent = link->pdev;
struct pci_bus *linkbus = parent->subordinate;
+ u32 aspm_enabled = aspm_get_enabled_states(link);
/* Enable only the states that were not explicitly disabled */
state &= (link->aspm_capable & ~link->aspm_disable);
@@ -832,11 +841,11 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
/* Spec says both ports must be in D0 before enabling PCI PM substates*/
if (parent->current_state != PCI_D0 || child->current_state != PCI_D0) {
state &= ~ASPM_STATE_L1_SS_PCIPM;
- state |= (link->aspm_enabled & ASPM_STATE_L1_SS_PCIPM);
+ state |= (aspm_enabled & ASPM_STATE_L1_SS_PCIPM);
}
/* Nothing to do if the link is already in the requested state */
- if (link->aspm_enabled == state)
+ if (aspm_enabled == state)
return;
/* Convert ASPM state to upstream/downstream ASPM register state */
if (state & ASPM_STATE_L0S_UP)
@@ -863,8 +872,6 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
pcie_config_aspm_dev(child, dwstream);
if (!(state & ASPM_STATE_L1))
pcie_config_aspm_dev(parent, upstream);
-
- link->aspm_enabled = state;
}
static void pcie_config_aspm_path(struct pcie_link_state *link)
@@ -1238,7 +1245,7 @@ bool pcie_aspm_enabled(struct pci_dev *pdev)
if (!link)
return false;
- return link->aspm_enabled;
+ return aspm_get_enabled_states(link);
}
EXPORT_SYMBOL_GPL(pcie_aspm_enabled);
@@ -1249,7 +1256,8 @@ static ssize_t aspm_attr_show_common(struct device *dev,
struct pci_dev *pdev = to_pci_dev(dev);
struct pcie_link_state *link = pcie_aspm_get_link(pdev);
- return sysfs_emit(buf, "%d\n", (link->aspm_enabled & state) ? 1 : 0);
+ return sysfs_emit(buf, "%d\n",
+ (aspm_get_enabled_states(link) & state) ? 1 : 0);
}
static ssize_t aspm_attr_store_common(struct device *dev,
--
2.20.1
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