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path: root/drivers/pci/pcie/aspm.c
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Diffstat (limited to 'drivers/pci/pcie/aspm.c')
-rw-r--r--drivers/pci/pcie/aspm.c170
1 files changed, 107 insertions, 63 deletions
diff --git a/drivers/pci/pcie/aspm.c b/drivers/pci/pcie/aspm.c
index 08d293f60fe..f289ca9bf18 100644
--- a/drivers/pci/pcie/aspm.c
+++ b/drivers/pci/pcie/aspm.c
@@ -26,6 +26,13 @@
#endif
#define MODULE_PARAM_PREFIX "pcie_aspm."
+/* Note: those are not register definitions */
+#define ASPM_STATE_L0S_UP (1) /* Upstream direction L0s state */
+#define ASPM_STATE_L0S_DW (2) /* Downstream direction L0s state */
+#define ASPM_STATE_L1 (4) /* L1 state */
+#define ASPM_STATE_L0S (ASPM_STATE_L0S_UP | ASPM_STATE_L0S_DW)
+#define ASPM_STATE_ALL (ASPM_STATE_L0S | ASPM_STATE_L1)
+
struct aspm_latency {
u32 l0s; /* L0s latency (nsec) */
u32 l1; /* L1 latency (nsec) */
@@ -40,19 +47,20 @@ struct pcie_link_state {
struct list_head link; /* node in parent's children list */
/* ASPM state */
- u32 aspm_support:2; /* Supported ASPM state */
- u32 aspm_enabled:2; /* Enabled ASPM state */
- u32 aspm_capable:2; /* Capable ASPM state with latency */
- u32 aspm_default:2; /* Default ASPM state by BIOS */
- u32 aspm_disable:2; /* Disabled ASPM state */
+ u32 aspm_support:3; /* Supported ASPM state */
+ u32 aspm_enabled:3; /* Enabled ASPM state */
+ u32 aspm_capable:3; /* Capable ASPM state with latency */
+ u32 aspm_default:3; /* Default ASPM state by BIOS */
+ u32 aspm_disable:3; /* 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 */
- /* Latencies */
- struct aspm_latency latency; /* Exit latency */
+ /* Exit latencies */
+ struct aspm_latency latency_up; /* Upstream direction exit latency */
+ struct aspm_latency latency_dw; /* Downstream direction exit latency */
/*
* Endpoint acceptable latencies. A pcie downstream port only
* has one slot under it, so at most there are 8 functions.
@@ -84,7 +92,7 @@ static int policy_to_aspm_state(struct pcie_link_state *link)
return 0;
case POLICY_POWERSAVE:
/* Enable ASPM L0s/L1 */
- return PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1;
+ return ASPM_STATE_ALL;
case POLICY_DEFAULT:
return link->aspm_default;
}
@@ -278,36 +286,35 @@ static u32 calc_l1_acceptable(u32 encoding)
return (1000 << encoding);
}
-static void pcie_aspm_get_cap_device(struct pci_dev *pdev, u32 *state,
- u32 *l0s, u32 *l1, u32 *enabled)
+struct aspm_register_info {
+ u32 support:2;
+ u32 enabled:2;
+ u32 latency_encoding_l0s;
+ u32 latency_encoding_l1;
+};
+
+static void pcie_get_aspm_reg(struct pci_dev *pdev,
+ struct aspm_register_info *info)
{
int pos;
u16 reg16;
- u32 reg32, encoding;
+ u32 reg32;
- *l0s = *l1 = *enabled = 0;
pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
pci_read_config_dword(pdev, pos + PCI_EXP_LNKCAP, &reg32);
- *state = (reg32 & PCI_EXP_LNKCAP_ASPMS) >> 10;
- if (*state != PCIE_LINK_STATE_L0S &&
- *state != (PCIE_LINK_STATE_L1 | PCIE_LINK_STATE_L0S))
- *state = 0;
- if (*state == 0)
- return;
-
- encoding = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;
- *l0s = calc_l0s_latency(encoding);
- if (*state & PCIE_LINK_STATE_L1) {
- encoding = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;
- *l1 = calc_l1_latency(encoding);
- }
+ info->support = (reg32 & PCI_EXP_LNKCAP_ASPMS) >> 10;
+ /* 00b and 10b are defined as "Reserved". */
+ if (info->support == PCIE_LINK_STATE_L1)
+ info->support = 0;
+ info->latency_encoding_l0s = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;
+ info->latency_encoding_l1 = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;
pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
- *enabled = reg16 & (PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1);
+ info->enabled = reg16 & PCI_EXP_LNKCTL_ASPMC;
}
static void pcie_aspm_check_latency(struct pci_dev *endpoint)
{
- u32 l1_switch_latency = 0;
+ u32 latency, l1_switch_latency = 0;
struct aspm_latency *acceptable;
struct pcie_link_state *link;
@@ -320,18 +327,24 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint)
acceptable = &link->acceptable[PCI_FUNC(endpoint->devfn)];
while (link) {
- /* Check L0s latency */
- if ((link->aspm_capable & PCIE_LINK_STATE_L0S) &&
- (link->latency.l0s > acceptable->l0s))
- link->aspm_capable &= ~PCIE_LINK_STATE_L0S;
+ /* Check upstream direction L0s latency */
+ if ((link->aspm_capable & ASPM_STATE_L0S_UP) &&
+ (link->latency_up.l0s > acceptable->l0s))
+ link->aspm_capable &= ~ASPM_STATE_L0S_UP;
+
+ /* Check downstream direction L0s latency */
+ if ((link->aspm_capable & ASPM_STATE_L0S_DW) &&
+ (link->latency_dw.l0s > acceptable->l0s))
+ link->aspm_capable &= ~ASPM_STATE_L0S_DW;
/*
* Check L1 latency.
* Every switch on the path to root complex need 1
* more microsecond for L1. Spec doesn't mention L0s.
*/
- if ((link->aspm_capable & PCIE_LINK_STATE_L1) &&
- (link->latency.l1 + l1_switch_latency > acceptable->l1))
- link->aspm_capable &= ~PCIE_LINK_STATE_L1;
+ latency = max_t(u32, link->latency_up.l1, link->latency_dw.l1);
+ if ((link->aspm_capable & ASPM_STATE_L1) &&
+ (latency + l1_switch_latency > acceptable->l1))
+ link->aspm_capable &= ~ASPM_STATE_L1;
l1_switch_latency += 1000;
link = link->parent;
@@ -340,33 +353,48 @@ static void pcie_aspm_check_latency(struct pci_dev *endpoint)
static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
{
- u32 support, l0s, l1, enabled;
struct pci_dev *child, *parent = link->pdev;
struct pci_bus *linkbus = parent->subordinate;
+ struct aspm_register_info upreg, dwreg;
if (blacklist) {
/* Set enabled/disable so that we will disable ASPM later */
- link->aspm_enabled = PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1;
- link->aspm_disable = PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1;
+ link->aspm_enabled = ASPM_STATE_ALL;
+ link->aspm_disable = ASPM_STATE_ALL;
return;
}
/* Configure common clock before checking latencies */
pcie_aspm_configure_common_clock(link);
- /* upstream component states */
- pcie_aspm_get_cap_device(parent, &support, &l0s, &l1, &enabled);
- link->aspm_support = support;
- link->latency.l0s = l0s;
- link->latency.l1 = l1;
- link->aspm_enabled = enabled;
-
- /* downstream component states, all functions have the same setting */
+ /* Get upstream/downstream components' register state */
+ pcie_get_aspm_reg(parent, &upreg);
child = list_entry(linkbus->devices.next, struct pci_dev, bus_list);
- pcie_aspm_get_cap_device(child, &support, &l0s, &l1, &enabled);
- link->aspm_support &= support;
- link->latency.l0s = max_t(u32, link->latency.l0s, l0s);
- link->latency.l1 = max_t(u32, link->latency.l1, l1);
+ pcie_get_aspm_reg(child, &dwreg);
+
+ /*
+ * Setup L0s state
+ *
+ * Note that we must not enable L0s in either direction on a
+ * given link unless components on both sides of the link each
+ * support L0s.
+ */
+ if (dwreg.support & upreg.support & PCIE_LINK_STATE_L0S)
+ link->aspm_support |= ASPM_STATE_L0S;
+ if (dwreg.enabled & PCIE_LINK_STATE_L0S)
+ link->aspm_enabled |= ASPM_STATE_L0S_UP;
+ if (upreg.enabled & PCIE_LINK_STATE_L0S)
+ link->aspm_enabled |= ASPM_STATE_L0S_DW;
+ link->latency_up.l0s = calc_l0s_latency(upreg.latency_encoding_l0s);
+ link->latency_dw.l0s = calc_l0s_latency(dwreg.latency_encoding_l0s);
+
+ /* Setup L1 state */
+ if (upreg.support & dwreg.support & PCIE_LINK_STATE_L1)
+ link->aspm_support |= ASPM_STATE_L1;
+ if (upreg.enabled & dwreg.enabled & PCIE_LINK_STATE_L1)
+ link->aspm_enabled |= ASPM_STATE_L1;
+ link->latency_up.l1 = calc_l1_latency(upreg.latency_encoding_l1);
+ link->latency_dw.l1 = calc_l1_latency(dwreg.latency_encoding_l1);
/* Save default state */
link->aspm_default = link->aspm_enabled;
@@ -379,8 +407,7 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
*/
list_for_each_entry(child, &linkbus->devices, bus_list) {
if (child->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
- link->aspm_disable =
- PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1;
+ link->aspm_disable = ASPM_STATE_ALL;
break;
}
}
@@ -409,19 +436,20 @@ static void pcie_aspm_cap_init(struct pcie_link_state *link, int blacklist)
}
}
-static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 state)
+static void pcie_config_aspm_dev(struct pci_dev *pdev, u32 val)
{
u16 reg16;
int pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
reg16 &= ~0x3;
- reg16 |= state;
+ reg16 |= val;
pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
}
static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
{
+ u32 upstream = 0, dwstream = 0;
struct pci_dev *child, *parent = link->pdev;
struct pci_bus *linkbus = parent->subordinate;
@@ -429,20 +457,27 @@ static void pcie_config_aspm_link(struct pcie_link_state *link, u32 state)
state &= (link->aspm_capable & ~link->aspm_disable);
if (link->aspm_enabled == state)
return;
+ /* Convert ASPM state to upstream/downstream ASPM register state */
+ if (state & ASPM_STATE_L0S_UP)
+ dwstream |= PCIE_LINK_STATE_L0S;
+ if (state & ASPM_STATE_L0S_DW)
+ upstream |= PCIE_LINK_STATE_L0S;
+ if (state & ASPM_STATE_L1) {
+ upstream |= PCIE_LINK_STATE_L1;
+ dwstream |= PCIE_LINK_STATE_L1;
+ }
/*
* Spec 2.0 suggests all functions should be configured the
* same setting for ASPM. Enabling ASPM L1 should be done in
* upstream component first and then downstream, and vice
* versa for disabling ASPM L1. Spec doesn't mention L0S.
*/
- if (state & PCIE_LINK_STATE_L1)
- pcie_config_aspm_dev(parent, state);
-
+ if (state & ASPM_STATE_L1)
+ pcie_config_aspm_dev(parent, upstream);
list_for_each_entry(child, &linkbus->devices, bus_list)
- pcie_config_aspm_dev(child, state);
-
- if (!(state & PCIE_LINK_STATE_L1))
- pcie_config_aspm_dev(parent, state);
+ pcie_config_aspm_dev(child, dwstream);
+ if (!(state & ASPM_STATE_L1))
+ pcie_config_aspm_dev(parent, upstream);
link->aspm_enabled = state;
}
@@ -673,7 +708,10 @@ void pci_disable_link_state(struct pci_dev *pdev, int state)
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
link = parent->link_state;
- link->aspm_disable |= state;
+ if (state & PCIE_LINK_STATE_L0S)
+ link->aspm_disable |= ASPM_STATE_L0S;
+ if (state & PCIE_LINK_STATE_L1)
+ link->aspm_disable |= ASPM_STATE_L1;
pcie_config_aspm_link(link, policy_to_aspm_state(link));
if (state & PCIE_LINK_STATE_CLKPM) {
@@ -742,11 +780,17 @@ static ssize_t link_state_store(struct device *dev,
{
struct pci_dev *pdev = to_pci_dev(dev);
struct pcie_link_state *link, *root = pdev->link_state->root;
- u32 state = buf[0] - '0';
+ u32 val = buf[0] - '0', state = 0;
- if (n < 1 || state > 3)
+ if (n < 1 || val > 3)
return -EINVAL;
+ /* Convert requested state to ASPM state */
+ if (val & PCIE_LINK_STATE_L0S)
+ state |= ASPM_STATE_L0S;
+ if (val & PCIE_LINK_STATE_L1)
+ state |= ASPM_STATE_L1;
+
down_read(&pci_bus_sem);
mutex_lock(&aspm_lock);
list_for_each_entry(link, &link_list, sibling) {
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-19 03:17:41 +0000