// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
/*
* Copyright(c) 2019 Intel Corporation.
*
*/
#include "aspm.h"
/* Time after which the timer interrupt will re-enable ASPM */
#define ASPM_TIMER_MS 1000
/* Time for which interrupts are ignored after a timer has been scheduled */
#define ASPM_RESCHED_TIMER_MS (ASPM_TIMER_MS / 2)
/* Two interrupts within this time trigger ASPM disable */
#define ASPM_TRIGGER_MS 1
#define ASPM_TRIGGER_NS (ASPM_TRIGGER_MS * 1000 * 1000ull)
#define ASPM_L1_SUPPORTED(reg) \
((((reg) & PCI_EXP_LNKCAP_ASPMS) >> 10) & 0x2)
uint aspm_mode = ASPM_MODE_DISABLED;
module_param_named(aspm, aspm_mode, uint, 0444);
MODULE_PARM_DESC(aspm, "PCIe ASPM: 0: disable, 1: enable, 2: dynamic");
static bool aspm_hw_l1_supported(struct hfi1_devdata *dd)
{
struct pci_dev *parent = dd->pcidev->bus->self;
u32 up, dn;
/*
* If the driver does not have access to the upstream component,
* it cannot support ASPM L1 at all.
*/
if (!parent)
return false;
pcie_capability_read_dword(dd->pcidev, PCI_EXP_LNKCAP, &dn);
dn = ASPM_L1_SUPPORTED(dn);
pcie_capability_read_dword(parent, PCI_EXP_LNKCAP, &up);
up = ASPM_L1_SUPPORTED(up);
/* ASPM works on A-step but is reported as not supported */
return (!!dn || is_ax(dd)) && !!up;
}
/* Set L1 entrance latency for slower entry to L1 */
static void aspm_hw_set_l1_ent_latency(struct hfi1_devdata *dd)
{
u32 l1_ent_lat = 0x4u;
u32 reg32;
pci_read_config_dword(dd->pcidev, PCIE_CFG_REG_PL3, ®32);
reg32 &= ~PCIE_CFG_REG_PL3_L1_ENT_LATENCY_SMASK;
reg32 |= l1_ent_lat << PCIE_CFG_REG_PL3_L1_ENT_LATENCY_SHIFT;
pci_write_config_dword(dd->pcidev, PCIE_CFG_REG_PL3, reg32);
}
static void aspm_hw_enable_l1(struct hfi1_devdata *dd)
{
struct pci_dev *parent = dd->pcidev->bus->self;
/*
* If the driver does not have access to the upstream component,
* it cannot support ASPM L1 at all.
*/
if (!parent)
return;
/* Enable ASPM L1 first in upstream component and then downstream */
pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
PCI_EXP_LNKCTL_ASPMC,
PCI_EXP_LNKCTL_ASPM_L1);
pcie_capability_clear_and_set_word(dd->pcidev, PCI_EXP_LNKCTL,
PCI_EXP_LNKCTL_ASPMC,
PCI_EXP_LNKCTL_ASPM_L1);
}
void aspm_hw_disable_l1(struct hfi1_devdata *dd)
{
struct pci_dev *parent = dd->pcidev->bus->self;
/* Disable ASPM L1 first in downstream component and then upstream */
pcie_capability_clear_and_set_word(dd->pcidev, PCI_EXP_LNKCTL,
PCI_EXP_LNKCTL_ASPMC, 0x0);
if (parent)
pcie_capability_clear_and_set_word(parent, PCI_EXP_LNKCTL,
PCI_EXP_LNKCTL_ASPMC, 0x0);
}
static void aspm_enable(struct hfi1_devdata *dd)
{
if (dd->aspm_enabled || aspm_mode == ASPM_MODE_DISABLED ||
!dd->aspm_supported)
return;
aspm_hw_enable_l1(dd);
dd->aspm_enabled = true;
}
static void aspm_disable(struct hfi1_devdata *dd)
{
if (!dd->aspm_enabled || aspm_mode == ASPM_MODE_ENABLED)
return;
aspm_hw_disable_l1(dd);
dd->aspm_enabled = false;
}
static void aspm_disable_inc(struct hfi1_devdata *dd)
{
unsigned long flags;
spin_lock_irqsave(&dd->aspm_lock, flags);
aspm_disable(dd);
atomic_inc(&dd->aspm_disabled_cnt);
spin_unlock_irqrestore(&dd->aspm_lock, flags);
}
static void aspm_enable_dec(struct hfi1_devdata *dd)
{
unsigned long flags;
spin_lock_irqsave(&dd->aspm_lock, flags);
if (atomic_dec_and_test(&dd->aspm_disabled_cnt))
aspm_enable(dd);
spin_unlock_irqrestore(&dd->aspm_lock, flags);
}
/* ASPM processing for each receive context interrupt */
void __aspm_ctx_disable(struct hfi1_ctxtdata *rcd)
{
bool restart_timer;
bool close_interrupts;
unsigned long flags;
ktime_t now, prev;
spin_lock_irqsave(&rcd->aspm_lock, flags);
/* PSM contexts are open */
if (!rcd->aspm_intr_enable)
goto unlock;
prev = rcd->aspm_ts_last_intr;
now = ktime_get();
rcd->aspm_ts_last_intr = now;
/* An interrupt pair close together in time */
close_interrupts = ktime_to_ns(ktime_sub(now, prev)) < ASPM_TRIGGER_NS;
/* Don't push out our timer till this much time has elapsed */
restart_timer = ktime_to_ns(ktime_sub(now, rcd->aspm_ts_timer_sched)) >
ASPM_RESCHED_TIMER_MS * NSEC_PER_MSEC;
restart_timer = restart_timer && close_interrupts;
/* Disable ASPM and schedule timer */
if (rcd->aspm_enabled && close_interrupts) {
aspm_disable_inc(rcd->dd);
rcd->aspm_enabled = false;
restart_timer = true;
}
if (restart_timer) {
mod_timer(&rcd->aspm_timer,
jiffies + msecs_to_jiffies(ASPM_TIMER_MS));
rcd->aspm_ts_timer_sched = now;
}
unlock:
spin_unlock_irqrestore(&rcd->aspm_lock, flags);
}
/* Timer function for re-enabling ASPM in the absence of interrupt activity */
static void aspm_ctx_timer_function(struct timer_list *t)
{
struct hfi1_ctxtdata *rcd = from_timer(rcd, t, aspm_timer);
unsigned long flags;
spin_lock_irqsave(&rcd->aspm_lock, flags);
aspm_enable_dec(rcd->dd);
rcd->aspm_enabled = true;
spin_unlock_irqrestore(&rcd->aspm_lock, flags);
}
/*
* Disable interrupt processing for verbs contexts when PSM or VNIC contexts
* are open.
*/
void aspm_disable_all(struct hfi1_devdata *dd)
{
struct hfi1_ctxtdata *rcd;
unsigned long flags;
u16 i;
for (i = 0; i < dd->first_dyn_alloc_ctxt; i++) {
rcd = hfi1_rcd_get_by_index(dd, i);
if (rcd) {
del_timer_sync(&rcd->aspm_timer);
spin_lock_irqsave(&rcd->aspm_lock, flags);
rcd->aspm_intr_enable = false;
spin_unlock_irqrestore(&rcd->aspm_lock, flags);
hfi1_rcd_put(rcd);
}
}
aspm_disable(dd);
atomic_set(&dd->aspm_disabled_cnt, 0);
}
/* Re-enable interrupt processing for verbs contexts */
void aspm_enable_all(struct hfi1_devdata *dd)
{
struct hfi1_ctxtdata *rcd;
unsigned long flags;
u16 i;
aspm_enable(dd);
if (aspm_mode != ASPM_MODE_DYNAMIC)
return;
for (i = 0; i < dd->first_dyn_alloc_ctxt; i++) {
rcd = hfi1_rcd_get_by_index(dd, i);
if (rcd) {
spin_lock_irqsave(&rcd->aspm_lock, flags);
rcd->aspm_intr_enable = true;
rcd->aspm_enabled = true;
spin_unlock_irqrestore(&rcd->aspm_lock, flags);
hfi1_rcd_put(rcd);
}
}
}
static void aspm_ctx_init(struct hfi1_ctxtdata *rcd)
{
spin_lock_init(&rcd->aspm_lock);
timer_setup(&rcd->aspm_timer, aspm_ctx_timer_function, 0);
rcd->aspm_intr_supported = rcd->dd->aspm_supported &&
aspm_mode == ASPM_MODE_DYNAMIC &&
rcd->ctxt < rcd->dd->first_dyn_alloc_ctxt;
}
void aspm_init(struct hfi1_devdata *dd)
{
struct hfi1_ctxtdata *rcd;
u16 i;
spin_lock_init(&dd->aspm_lock);
dd->aspm_supported = aspm_hw_l1_supported(dd);
for (i = 0; i < dd->first_dyn_alloc_ctxt; i++) {
rcd = hfi1_rcd_get_by_index(dd, i);
if (rcd)
aspm_ctx_init(rcd);
hfi1_rcd_put(rcd);
}
/* Start with ASPM disabled */
aspm_hw_set_l1_ent_latency(dd);
dd->aspm_enabled = false;
aspm_hw_disable_l1(dd);
/* Now turn on ASPM if configured */
aspm_enable_all(dd);
}
void aspm_exit(struct hfi1_devdata *dd)
{
aspm_disable_all(dd);
/* Turn on ASPM on exit to conserve power */
aspm_enable(dd);
}
