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SubjectRe: [PATCH]PCIE ASPM support - takes 3
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On Tue, 2008-01-22 at 14:58 -0800, Greg KH wrote:
> On Fri, Jan 18, 2008 at 09:56:28AM +0800, Shaohua Li wrote:
> > v3->v2, fixed the issues Matthew Wilcox raised.
> >
> > PCI Express ASPM defines a protocol for PCI Express components in the D0
> > state to reduce Link power by placing their Links into a low power state
> > and instructing the other end of the Link to do likewise. This
> > capability allows hardware-autonomous, dynamic Link power reduction
> > beyond what is achievable by software-only controlled power management.
> > However, The device should be configured by software appropriately.
> > Enabling ASPM will save power, but will introduce device latency.
> >
> > This patch adds ASPM support in Linux. It introduces a global policy for
> > ASPM, a sysfs file /sys/module/pcie_aspm/parameters/policy can control
> > it. The interface can be used as a boot option too. Currently we have
> > below setting:
> > -default, BIOS default setting
> > -powersave, highest power saving mode, enable all available ASPM
> > state
> > and clock power management
> > -performance, highest performance, disable ASPM and clock power
> > management
> > By default, the 'default' policy is used currently.
> >
> > In my test, power difference between powersave mode and performance mode
> > is about 1.3w in a system with 3 PCIE links.
> >
> > please review, any comments will be appreciated.
>
> Can you please fix up all of the warnings that checkpatch.pl and sparse
> produce from this patch?
>
> Also, one small thing:
>
> > --- linux.orig/include/linux/pci.h 2008-01-16 15:59:42.000000000 +0800
> > +++ linux/include/linux/pci.h 2008-01-18 09:41:20.000000000 +0800
> > @@ -164,6 +164,10 @@ struct pci_dev {
> > this is D0-D3, D0 being fully functional,
> > and D3 being off. */
> >
> > +#ifdef CONFIG_PCIEASPM
> > + void *link_state; /* ASPM link state. */
> > +#endif
>
> Can we make this a "real" pointer to a structure? I note that you use
> two different structures here in this pointer, should you really do
> that? It's good to get type-checks whereever possible.
The structure is just for internal use of ASPM, just don't want make it
global.

Fixed, now sparse and checkpatch.pl haven't warning.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
---
drivers/pci/pci-sysfs.c | 5
drivers/pci/pci.c | 4
drivers/pci/pcie/Kconfig | 20 +
drivers/pci/pcie/Makefile | 3
drivers/pci/pcie/aspm.c | 818 ++++++++++++++++++++++++++++++++++++++++++++++
drivers/pci/probe.c | 5
drivers/pci/remove.c | 4
include/linux/aspm.h | 44 ++
include/linux/pci.h | 4
include/linux/pci_regs.h | 8
10 files changed, 915 insertions(+)
Index: linux/drivers/pci/pcie/Makefile
===================================================================
--- linux.orig/drivers/pci/pcie/Makefile 2008-01-23 10:14:14.000000000 +0800
+++ linux/drivers/pci/pcie/Makefile 2008-01-23 10:14:46.000000000 +0800
@@ -2,6 +2,9 @@
# Makefile for PCI-Express PORT Driver
#

+# Build PCI Express ASPM if needed
+obj-$(CONFIG_PCIEASPM) += aspm.o
+
pcieportdrv-y := portdrv_core.o portdrv_pci.o portdrv_bus.o

obj-$(CONFIG_PCIEPORTBUS) += pcieportdrv.o
Index: linux/drivers/pci/pcie/aspm.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux/drivers/pci/pcie/aspm.c 2008-01-23 10:14:46.000000000 +0800
@@ -0,0 +1,818 @@
+/*
+ * File: drivers/pci/pcie/aspm.c
+ * Enabling PCIE link L0s/L1 state and Clock Power Management
+ *
+ * Copyright (C) 2007 Intel
+ * Copyright (C) Zhang Yanmin (yanmin.zhang@intel.com)
+ * Copyright (C) Shaohua Li (shaohua.li@intel.com)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/pci.h>
+#include <linux/pci_regs.h>
+#include <linux/errno.h>
+#include <linux/pm.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/aspm.h>
+#include <acpi/acpi_bus.h>
+#include <linux/pci-acpi.h>
+#include "../pci.h"
+
+#ifdef MODULE_PARAM_PREFIX
+#undef MODULE_PARAM_PREFIX
+#endif
+#define MODULE_PARAM_PREFIX "pcie_aspm."
+
+/* only for downstream port */
+struct link_state {
+ struct list_head sibiling;
+ struct pci_dev *pdev;
+
+ /* ASPM state */
+ unsigned int support_state;
+ unsigned int enabled_state;
+ unsigned int bios_aspm_state;
+ /* upstream component */
+ unsigned int l0s_upper_latency;
+ unsigned int l1_upper_latency;
+ /* downstream component */
+ unsigned int l0s_down_latency;
+ unsigned int l1_down_latency;
+ /* Clock PM state*/
+ unsigned int clk_pm_capable;
+ unsigned int clk_pm_enabled;
+ unsigned int bios_clk_state;
+
+};
+
+/* Only for endpoint */
+struct endpoint_state {
+ unsigned int l0s_acceptable_latency;
+ unsigned int l1_acceptable_latency;
+};
+
+static int aspm_disabled;
+static DEFINE_MUTEX(aspm_lock);
+static LIST_HEAD(link_list);
+
+#define POLICY_DEFAULT 0 /* BIOS default setting */
+#define POLICY_PERFORMANCE 1 /* high performance */
+#define POLICY_POWERSAVE 2 /* high power saving */
+static int aspm_policy;
+static const char *policy_str[] = {
+ [POLICY_DEFAULT] = "default",
+ [POLICY_PERFORMANCE] = "performance",
+ [POLICY_POWERSAVE] = "powersave"
+};
+
+static int policy_to_aspm_state(struct pci_dev *pdev)
+{
+ struct link_state *link_state = pdev->link_state;
+
+ switch (aspm_policy) {
+ case POLICY_PERFORMANCE:
+ /* Disable ASPM and Clock PM */
+ return 0;
+ case POLICY_POWERSAVE:
+ /* Enable ASPM L0s/L1 */
+ return PCIE_LINK_STATE_L0S|PCIE_LINK_STATE_L1;
+ case POLICY_DEFAULT:
+ return link_state->bios_aspm_state;
+ }
+ return 0;
+}
+
+static int policy_to_clkpm_state(struct pci_dev *pdev)
+{
+ struct link_state *link_state = pdev->link_state;
+
+ switch (aspm_policy) {
+ case POLICY_PERFORMANCE:
+ /* Disable ASPM and Clock PM */
+ return 0;
+ case POLICY_POWERSAVE:
+ /* Disable Clock PM */
+ return 1;
+ case POLICY_DEFAULT:
+ return link_state->bios_clk_state;
+ }
+ return 0;
+}
+
+static void pcie_set_clock_pm(struct pci_dev *pdev, int enable)
+{
+ struct pci_dev *child_dev;
+ int pos;
+ u16 reg16;
+ struct link_state *link_state = pdev->link_state;
+
+ list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
+ pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
+ if (!pos)
+ return;
+ pci_read_config_word(child_dev, pos + PCI_EXP_LNKCTL, &reg16);
+ if (enable)
+ reg16 |= PCI_EXP_LNKCTL_CLKREQ_EN;
+ else
+ reg16 &= ~PCI_EXP_LNKCTL_CLKREQ_EN;
+ pci_write_config_word(child_dev, pos + PCI_EXP_LNKCTL, reg16);
+ }
+ link_state->clk_pm_enabled = !!enable;
+}
+
+static void pcie_check_clock_pm(struct pci_dev *pdev)
+{
+ int pos;
+ u32 reg32;
+ u16 reg16;
+ int capable = 1, enabled = 1;
+ struct pci_dev *child_dev;
+ struct link_state *link_state = pdev->link_state;
+
+ /* All functions should have the same cap and state, take the worst */
+ list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
+ pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
+ if (!pos)
+ return;
+ pci_read_config_dword(child_dev, pos + PCI_EXP_LNKCAP, &reg32);
+ if (!(reg32 & PCI_EXP_LNKCAP_CLKPM)) {
+ capable = 0;
+ enabled = 0;
+ break;
+ }
+ pci_read_config_word(child_dev, pos + PCI_EXP_LNKCTL, &reg16);
+ if (!(reg16 & PCI_EXP_LNKCTL_CLKREQ_EN))
+ enabled = 0;
+ }
+ link_state->clk_pm_capable = capable;
+ link_state->clk_pm_enabled = enabled;
+ link_state->bios_clk_state = enabled;
+ pcie_set_clock_pm(pdev, policy_to_clkpm_state(pdev));
+}
+
+/*
+ * pcie_aspm_configure_common_clock: check if the 2 ends of a link
+ * could use common clock. If they are, configure them to use the
+ * common clock. That will reduce the ASPM state exit latency.
+ */
+static void pcie_aspm_configure_common_clock(struct pci_dev *pdev)
+{
+ int pos, child_pos;
+ u16 reg16 = 0;
+ struct pci_dev *child_dev;
+ int same_clock = 1;
+
+ /*
+ * all functions of a slot should have the same Slot Clock
+ * Configuration, so just check one function
+ * */
+ child_dev = list_entry(pdev->subordinate->devices.next, struct pci_dev,
+ bus_list);
+ BUG_ON(!child_dev->is_pcie);
+
+ /* Check downstream component if bit Slot Clock Configuration is 1 */
+ child_pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
+ pci_read_config_word(child_dev, child_pos + PCI_EXP_LNKSTA, &reg16);
+ if (!(reg16 & PCI_EXP_LNKSTA_SLC))
+ same_clock = 0;
+
+ /* Check upstream component if bit Slot Clock Configuration is 1 */
+ pos = pci_find_capability(pdev, PCI_CAP_ID_EXP);
+ pci_read_config_word(pdev, pos + PCI_EXP_LNKSTA, &reg16);
+ if (!(reg16 & PCI_EXP_LNKSTA_SLC))
+ same_clock = 0;
+
+ /* Configure downstream component, all functions */
+ list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
+ child_pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
+ pci_read_config_word(child_dev, child_pos + PCI_EXP_LNKCTL,
+ &reg16);
+ if (same_clock)
+ reg16 |= PCI_EXP_LNKCTL_CCC;
+ else
+ reg16 &= ~PCI_EXP_LNKCTL_CCC;
+ pci_write_config_word(child_dev, child_pos + PCI_EXP_LNKCTL,
+ reg16);
+ }
+
+ /* Configure upstream component */
+ pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
+ if (same_clock)
+ reg16 |= PCI_EXP_LNKCTL_CCC;
+ else
+ reg16 &= ~PCI_EXP_LNKCTL_CCC;
+ pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
+
+ /* retrain link */
+ reg16 |= PCI_EXP_LNKCTL_RL;
+ pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
+
+ /* Wait for link training end */
+ while (1) {
+ pci_read_config_word(pdev, pos + PCI_EXP_LNKSTA, &reg16);
+ if (!(reg16 & PCI_EXP_LNKSTA_LT))
+ break;
+ cpu_relax();
+ }
+}
+
+/*
+ * calc_L0S_latency: Convert L0s latency encoding to ns
+ */
+static unsigned int calc_L0S_latency(unsigned int latency_encoding, int ac)
+{
+ unsigned int ns = 64;
+
+ if (latency_encoding == 0x7) {
+ if (ac)
+ ns = -1U;
+ else
+ ns = 5*1000; /* > 4us */
+ } else
+ ns *= (1 << latency_encoding);
+ return ns;
+}
+
+/*
+ * calc_L1_latency: Convert L1 latency encoding to ns
+ */
+static unsigned int calc_L1_latency(unsigned int latency_encoding, int ac)
+{
+ unsigned int ns = 1000;
+
+ if (latency_encoding == 0x7) {
+ if (ac)
+ ns = -1U;
+ else
+ ns = 65*1000; /* > 64us */
+ } else
+ ns *= (1 << latency_encoding);
+ return ns;
+}
+
+static void pcie_aspm_get_cap_device(struct pci_dev *pdev, u32 *state,
+ unsigned int *l0s, unsigned int *l1, unsigned int *enabled)
+{
+ int pos;
+ u16 reg16;
+ u32 reg32;
+ unsigned int latency;
+
+ 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;
+
+ latency = (reg32 & PCI_EXP_LNKCAP_L0SEL) >> 12;
+ *l0s = calc_L0S_latency(latency, 0);
+ if (*state & PCIE_LINK_STATE_L1) {
+ latency = (reg32 & PCI_EXP_LNKCAP_L1EL) >> 15;
+ *l1 = calc_L1_latency(latency, 0);
+ }
+ pci_read_config_word(pdev, pos + PCI_EXP_LNKCTL, &reg16);
+ *enabled = reg16 & (PCIE_LINK_STATE_L0S|PCIE_LINK_STATE_L1);
+}
+
+static void pcie_aspm_cap_init(struct pci_dev *pdev)
+{
+ struct pci_dev *child_dev;
+ u32 state, tmp;
+ struct link_state *link_state = pdev->link_state;
+
+ /* upstream component states */
+ pcie_aspm_get_cap_device(pdev, &link_state->support_state,
+ &link_state->l0s_upper_latency,
+ &link_state->l1_upper_latency,
+ &link_state->enabled_state);
+ /* downstream component states, all functions have the same setting */
+ child_dev = list_entry(pdev->subordinate->devices.next, struct pci_dev,
+ bus_list);
+ pcie_aspm_get_cap_device(child_dev, &state,
+ &link_state->l0s_down_latency,
+ &link_state->l1_down_latency,
+ &tmp);
+ link_state->support_state &= state;
+ if (!link_state->support_state)
+ return;
+ link_state->enabled_state &= link_state->support_state;
+ link_state->bios_aspm_state = link_state->enabled_state;
+
+ /* ENDPOINT states*/
+ list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
+ int pos;
+ u32 reg32;
+ unsigned int latency;
+ struct endpoint_state *ep_state;
+
+ if (child_dev->pcie_type != PCI_EXP_TYPE_ENDPOINT &&
+ child_dev->pcie_type != PCI_EXP_TYPE_LEG_END)
+ continue;
+
+ ep_state = child_dev->link_state;
+ pos = pci_find_capability(child_dev, PCI_CAP_ID_EXP);
+ pci_read_config_dword(child_dev, pos + PCI_EXP_DEVCAP, &reg32);
+ latency = (reg32 & PCI_EXP_DEVCAP_L0S) >> 6;
+ latency = calc_L0S_latency(latency, 1);
+ ep_state->l0s_acceptable_latency = latency;
+ if (link_state->support_state & PCIE_LINK_STATE_L1) {
+ latency = (reg32 & PCI_EXP_DEVCAP_L1) >> 9;
+ latency = calc_L1_latency(latency, 1);
+ ep_state->l1_acceptable_latency = latency;
+ }
+ }
+}
+
+static unsigned int __pcie_aspm_check_state_one(struct pci_dev *pdev,
+ unsigned int state)
+{
+ struct pci_dev *parent_dev, *tmp_dev;
+ unsigned int latency, l1_latency = 0;
+ struct link_state *link_state;
+ struct endpoint_state *ep_state = pdev->link_state;
+
+ parent_dev = pdev->bus->self;
+ link_state = parent_dev->link_state;
+ state &= link_state->support_state;
+ if (state == 0)
+ return 0;
+
+ /*
+ * Check latency for endpoint device.
+ * TBD: The latency from the endpoint to root complex vary per
+ * switch's upstream link state above the device. Here we just do a
+ * simple check which assumes all links above the device can be in L1
+ * state, that is we just consider the worst case. If switch's upstream
+ * link can't be put into L0S/L1, then our check is too strictly.
+ */
+ tmp_dev = pdev;
+ while (state & (PCIE_LINK_STATE_L0S | PCIE_LINK_STATE_L1)) {
+ parent_dev = tmp_dev->bus->self;
+ link_state = parent_dev->link_state;
+ if (state & PCIE_LINK_STATE_L0S) {
+ latency = max_t(unsigned int,
+ link_state->l0s_upper_latency,
+ link_state->l0s_down_latency);
+ if (latency > ep_state->l0s_acceptable_latency)
+ state &= ~PCIE_LINK_STATE_L0S;
+ }
+ if (state & PCIE_LINK_STATE_L1) {
+ latency = max_t(unsigned int,
+ link_state->l1_upper_latency,
+ link_state->l1_down_latency);
+ if (latency + l1_latency >
+ ep_state->l1_acceptable_latency)
+ state &= ~PCIE_LINK_STATE_L1;
+ }
+ if (!parent_dev->bus->self) /* parent_dev is a root port */
+ break;
+ else {
+ /*
+ * parent_dev is the downstream port of a switch, make
+ * tmp_dev the upstream port of the switch
+ */
+ tmp_dev = parent_dev->bus->self;
+ /*
+ * every switch on the path to root complex need 1 more
+ * microsecond for L1. Spec doesn't mention L0S.
+ */
+ if (state & PCIE_LINK_STATE_L1)
+ l1_latency += 1000;
+ }
+ }
+ return state;
+}
+
+static unsigned int pcie_aspm_check_state(struct pci_dev *pdev,
+ unsigned int state)
+{
+ struct pci_dev *child_dev;
+
+ /* If no child, disable the link */
+ if (list_empty(&pdev->subordinate->devices))
+ return 0;
+ list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
+ if (child_dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
+ /*
+ * If downstream component of a link is pci bridge, we
+ * disable ASPM for now for the link
+ * */
+ state = 0;
+ break;
+ }
+ if ((child_dev->pcie_type != PCI_EXP_TYPE_ENDPOINT &&
+ child_dev->pcie_type != PCI_EXP_TYPE_LEG_END) ||
+ !child_dev->link_state)
+ continue;
+ /* Device not in D0 doesn't need check latency */
+ if (child_dev->current_state == PCI_D1 ||
+ child_dev->current_state == PCI_D2 ||
+ child_dev->current_state == PCI_D3hot ||
+ child_dev->current_state == PCI_D3cold)
+ continue;
+ state = __pcie_aspm_check_state_one(child_dev, state);
+ }
+ return state;
+}
+
+static void __pcie_aspm_config_one_dev(struct pci_dev *pdev, unsigned int state)
+{
+ 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;
+ pci_write_config_word(pdev, pos + PCI_EXP_LNKCTL, reg16);
+}
+
+static void __pcie_aspm_config_link(struct pci_dev *pdev, unsigned int state)
+{
+ struct pci_dev *child_dev;
+ int valid = 1;
+ struct link_state *link_state = pdev->link_state;
+
+ /*
+ * if the downstream component has pci bridge function, don't do ASPM
+ * now
+ */
+ list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
+ if (child_dev->pcie_type == PCI_EXP_TYPE_PCI_BRIDGE) {
+ valid = 0;
+ break;
+ }
+ }
+ if (!valid)
+ return;
+
+ /*
+ * 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_aspm_config_one_dev(pdev, state);
+
+ list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list)
+ __pcie_aspm_config_one_dev(child_dev, state);
+
+ if (!(state & PCIE_LINK_STATE_L1))
+ __pcie_aspm_config_one_dev(pdev, state);
+
+ link_state->enabled_state = state;
+}
+
+static void __pcie_aspm_configure_link_state(struct pci_dev *pdev,
+ unsigned int state)
+{
+ struct link_state *link_state = pdev->link_state;
+
+ if (link_state->support_state == 0)
+ return;
+ state &= PCIE_LINK_STATE_L0S|PCIE_LINK_STATE_L1;
+
+ /* state 0 means disabling aspm */
+ state = pcie_aspm_check_state(pdev, state);
+ if (link_state->enabled_state == state)
+ return;
+ __pcie_aspm_config_link(pdev, state);
+}
+
+/*
+ * pcie_aspm_configure_link_state: enable/disable PCI express link state
+ * @pdev: the root port or switch downstream port
+ */
+static void pcie_aspm_configure_link_state(struct pci_dev *pdev,
+ unsigned int state)
+{
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ __pcie_aspm_configure_link_state(pdev, state);
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+}
+
+static void free_link_state(struct pci_dev *pdev)
+{
+ struct pci_dev *child_dev;
+
+ list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
+ kfree(child_dev->link_state);
+ child_dev->link_state = NULL;
+ }
+ kfree(pdev->link_state);
+ pdev->link_state = NULL;
+}
+
+/*
+ * pcie_aspm_init_link_state: Initiate PCI express link state.
+ * It is called after the pcie and its children devices are scaned.
+ * @pdev: the root port or switch downstream port
+ */
+void pcie_aspm_init_link_state(struct pci_dev *pdev)
+{
+ unsigned int state;
+ struct link_state *link_state;
+ struct pci_dev *child_dev;
+ struct endpoint_state *ep_state;
+ int error = 0;
+
+ if (aspm_disabled || !pdev->is_pcie || pdev->link_state)
+ return;
+ if (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
+ pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)
+ return;
+ down_read(&pci_bus_sem);
+ if (list_empty(&pdev->subordinate->devices))
+ goto out;
+
+ mutex_lock(&aspm_lock);
+
+ link_state = kzalloc(sizeof(*link_state), GFP_KERNEL);
+ if (!link_state)
+ goto unlock_out;
+ pdev->link_state = link_state;
+ list_for_each_entry(child_dev, &pdev->subordinate->devices, bus_list) {
+ ep_state = kzalloc(sizeof(*ep_state), GFP_KERNEL);
+ if (!ep_state) {
+ error = 1;
+ goto unlock_out;
+ }
+ child_dev->link_state = ep_state;
+ }
+
+ pcie_aspm_configure_common_clock(pdev);
+
+ pcie_aspm_cap_init(pdev);
+
+ /* config link state to avoid BIOS error */
+ state = pcie_aspm_check_state(pdev, policy_to_aspm_state(pdev));
+ __pcie_aspm_config_link(pdev, state);
+
+ pcie_check_clock_pm(pdev);
+
+ link_state->pdev = pdev;
+ list_add(&link_state->sibiling, &link_list);
+
+unlock_out:
+ if (error)
+ free_link_state(pdev);
+ mutex_unlock(&aspm_lock);
+out:
+ up_read(&pci_bus_sem);
+}
+
+/* @pdev: the endpoint device */
+void pcie_aspm_exit_link_state(struct pci_dev *pdev)
+{
+ struct pci_dev *parent = pdev->bus->self;
+ struct link_state *link_state = parent->link_state;
+
+ if (aspm_disabled || !pdev->is_pcie || !parent || !link_state)
+ return;
+ if (parent->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
+ parent->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)
+ return;
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+
+ /*
+ * All PCIe functions are in one slot, remove one function will remove
+ * the the whole slot, so just wait
+ */
+ if (!list_empty(&parent->subordinate->devices)) {
+ kfree(pdev->link_state);
+ pdev->link_state = NULL;
+ goto out;
+ }
+
+ /* All functions are removed, so just disable ASPM for the link */
+ __pcie_aspm_config_one_dev(parent, 0);
+ list_del(&link_state->sibiling);
+ /* Clock PM is for endpoint device */
+
+ free_link_state(parent);
+out:
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+}
+
+/* @pdev: the root port or switch downstream port */
+void pcie_aspm_pm_state_change(struct pci_dev *pdev)
+{
+ struct link_state *link_state = pdev->link_state;
+
+ if (aspm_disabled || !pdev->is_pcie || !pdev->link_state)
+ return;
+ if (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
+ pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM)
+ return;
+ /*
+ * devices changed PM state, we should recheck if latency meets all
+ * functions' requirement
+ */
+ pcie_aspm_configure_link_state(pdev, link_state->enabled_state);
+}
+
+/*
+ * pci_disable_link_state - disable pci device's link state, so the link will
+ * never enter specific states
+ */
+void pci_disable_link_state(struct pci_dev *pdev, int state)
+{
+ struct pci_dev *parent = pdev->bus->self;
+ struct link_state *link_state;
+
+ if (aspm_disabled || !pdev->is_pcie || !pdev->link_state)
+ return;
+ if (pdev->pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
+ pdev->pcie_type == PCI_EXP_TYPE_DOWNSTREAM)
+ parent = pdev;
+ if (!parent)
+ return;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ link_state = parent->link_state;
+ link_state->support_state &=
+ ~(state & (PCIE_LINK_STATE_L0S|PCIE_LINK_STATE_L1));
+ if (state & PCIE_LINK_STATE_CLKPM)
+ link_state->clk_pm_capable = 0;
+
+ __pcie_aspm_configure_link_state(parent, link_state->enabled_state);
+ if (!link_state->clk_pm_capable && link_state->clk_pm_enabled)
+ pcie_set_clock_pm(parent, 0);
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+}
+EXPORT_SYMBOL(pci_disable_link_state);
+
+static int pcie_aspm_set_policy(const char *val, struct kernel_param *kp)
+{
+ int i;
+ struct pci_dev *pdev;
+ struct link_state *link_state;
+
+ for (i = 0; i < ARRAY_SIZE(policy_str); i++)
+ if (!strncmp(val, policy_str[i], strlen(policy_str[i])))
+ break;
+ if (i >= ARRAY_SIZE(policy_str))
+ return -EINVAL;
+ if (i == aspm_policy)
+ return 0;
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ aspm_policy = i;
+ list_for_each_entry(link_state, &link_list, sibiling) {
+ pdev = link_state->pdev;
+ __pcie_aspm_configure_link_state(pdev,
+ policy_to_aspm_state(pdev));
+ if (link_state->clk_pm_capable &&
+ link_state->clk_pm_enabled != policy_to_clkpm_state(pdev))
+ pcie_set_clock_pm(pdev, policy_to_clkpm_state(pdev));
+
+ }
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+ return 0;
+}
+
+static int pcie_aspm_get_policy(char *buffer, struct kernel_param *kp)
+{
+ int i, cnt = 0;
+ for (i = 0; i < ARRAY_SIZE(policy_str); i++)
+ if (i == aspm_policy)
+ cnt += sprintf(buffer + cnt, "[%s] ", policy_str[i]);
+ else
+ cnt += sprintf(buffer + cnt, "%s ", policy_str[i]);
+ return cnt;
+}
+
+module_param_call(policy, pcie_aspm_set_policy, pcie_aspm_get_policy,
+ NULL, 0644);
+
+#ifdef CONFIG_PCIEASPM_DEBUG
+static ssize_t link_state_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pci_dev *pci_device = to_pci_dev(dev);
+ struct link_state *link_state = pci_device->link_state;
+
+ return sprintf(buf, "%d\n", link_state->enabled_state);
+}
+
+static ssize_t link_state_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t n)
+{
+ struct pci_dev *pci_device = to_pci_dev(dev);
+ int state;
+
+ if (n < 1)
+ return -EINVAL;
+ state = buf[0]-'0';
+ if (state >= 0 && state <= 3) {
+ /* setup link aspm state */
+ pcie_aspm_configure_link_state(pci_device, state);
+ return n;
+ }
+
+ return -EINVAL;
+}
+
+static ssize_t clk_ctl_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct pci_dev *pci_device = to_pci_dev(dev);
+ struct link_state *link_state = pci_device->link_state;
+
+ return sprintf(buf, "%d\n", link_state->clk_pm_enabled);
+}
+
+static ssize_t clk_ctl_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t n)
+{
+ struct pci_dev *pci_device = to_pci_dev(dev);
+ int state;
+
+ if (n < 1)
+ return -EINVAL;
+ state = buf[0]-'0';
+
+ down_read(&pci_bus_sem);
+ mutex_lock(&aspm_lock);
+ pcie_set_clock_pm(pci_device, !!state);
+ mutex_unlock(&aspm_lock);
+ up_read(&pci_bus_sem);
+
+ return n;
+}
+
+static DEVICE_ATTR(link_state, 0644, link_state_show, link_state_store);
+static DEVICE_ATTR(clk_ctl, 0644, clk_ctl_show, clk_ctl_store);
+
+static char power_group[] = "power";
+void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev)
+{
+ struct link_state *link_state = pdev->link_state;
+
+ if (!pdev->is_pcie || (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
+ pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
+ return;
+
+ if (link_state->support_state)
+ sysfs_add_file_to_group(&pdev->dev.kobj,
+ &dev_attr_link_state.attr, power_group);
+ if (link_state->clk_pm_capable)
+ sysfs_add_file_to_group(&pdev->dev.kobj,
+ &dev_attr_clk_ctl.attr, power_group);
+}
+
+void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev)
+{
+ struct link_state *link_state = pdev->link_state;
+
+ if (!pdev->is_pcie || (pdev->pcie_type != PCI_EXP_TYPE_ROOT_PORT &&
+ pdev->pcie_type != PCI_EXP_TYPE_DOWNSTREAM))
+ return;
+
+ if (link_state->support_state)
+ sysfs_remove_file_from_group(&pdev->dev.kobj,
+ &dev_attr_link_state.attr, power_group);
+ if (link_state->clk_pm_capable)
+ sysfs_remove_file_from_group(&pdev->dev.kobj,
+ &dev_attr_clk_ctl.attr, power_group);
+}
+#endif
+
+static int __init pcie_aspm_disable(char *str)
+{
+ aspm_disabled = 1;
+ return 1;
+}
+
+__setup("pcie_noaspm", pcie_aspm_disable);
+
+static int __init pcie_aspm_init(void)
+{
+ if (aspm_disabled)
+ return 0;
+ pci_osc_support_set(OSC_ACTIVE_STATE_PWR_SUPPORT|
+ OSC_CLOCK_PWR_CAPABILITY_SUPPORT);
+ return 0;
+}
+
+fs_initcall(pcie_aspm_init);
Index: linux/include/linux/aspm.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux/include/linux/aspm.h 2008-01-23 10:14:46.000000000 +0800
@@ -0,0 +1,44 @@
+/*
+ * aspm.h
+ *
+ * PCI Express ASPM defines and function prototypes
+ *
+ * Copyright (C) 2007 Intel Corp.
+ * Zhang Yanmin (yanmin.zhang@intel.com)
+ * Shaohua Li (shaohua.li@intel.com)
+ *
+ * For more information, please consult the following manuals (look at
+ * http://www.pcisig.com/ for how to get them):
+ *
+ * PCI Express Specification
+ */
+
+#ifndef LINUX_ASPM_H
+#define LINUX_ASPM_H
+
+#include <linux/pci.h>
+
+#define PCIE_LINK_STATE_L0S 1
+#define PCIE_LINK_STATE_L1 2
+#define PCIE_LINK_STATE_CLKPM 4
+
+#ifdef CONFIG_PCIEASPM
+extern void pcie_aspm_init_link_state(struct pci_dev *pdev);
+extern void pcie_aspm_exit_link_state(struct pci_dev *pdev);
+extern void pcie_aspm_pm_state_change(struct pci_dev *pdev);
+extern void pci_disable_link_state(struct pci_dev *pdev, int state);
+#else
+#define pcie_aspm_init_link_state(pdev) do {} while (0)
+#define pcie_aspm_exit_link_state(pdev) do {} while (0)
+#define pcie_aspm_pm_state_change(pdev) do {} while (0)
+#define pci_disable_link_state(pdev, state) do {} while (0)
+#endif
+
+#ifdef CONFIG_PCIEASPM_DEBUG /* this depends on CONFIG_PCIEASPM */
+extern void pcie_aspm_create_sysfs_dev_files(struct pci_dev *pdev);
+extern void pcie_aspm_remove_sysfs_dev_files(struct pci_dev *pdev);
+#else
+#define pcie_aspm_create_sysfs_dev_files(pdev) do {} while (0)
+#define pcie_aspm_remove_sysfs_dev_files(pdev) do {} while (0)
+#endif
+#endif /* LINUX_ASPM_H */
Index: linux/drivers/pci/pcie/Kconfig
===================================================================
--- linux.orig/drivers/pci/pcie/Kconfig 2008-01-23 10:14:14.000000000 +0800
+++ linux/drivers/pci/pcie/Kconfig 2008-01-23 10:14:46.000000000 +0800
@@ -26,3 +26,23 @@ config HOTPLUG_PCI_PCIE
When in doubt, say N.

source "drivers/pci/pcie/aer/Kconfig"
+
+#
+# PCI Express ASPM
+#
+config PCIEASPM
+ bool "PCI Express ASPM support(Experimental)"
+ depends on PCI && EXPERIMENTAL
+ default y
+ help
+ This enables PCI Express ASPM (Active State Power Management) and
+ Clock Power Management. ASPM supports state L0/L0s/L1.
+
+ When in doubt, say N.
+config PCIEASPM_DEBUG
+ bool "Debug PCI Express ASPM"
+ depends on PCIEASPM
+ default n
+ help
+ This enables PCI Express ASPM debug support. It will add per-device
+ interface to control ASPM.
Index: linux/include/linux/pci.h
===================================================================
--- linux.orig/include/linux/pci.h 2008-01-23 10:14:14.000000000 +0800
+++ linux/include/linux/pci.h 2008-01-23 10:14:46.000000000 +0800
@@ -164,6 +164,10 @@ struct pci_dev {
this is D0-D3, D0 being fully functional,
and D3 being off. */

+#ifdef CONFIG_PCIEASPM
+ void *link_state; /* ASPM link state. */
+#endif
+
pci_channel_state_t error_state; /* current connectivity state */
struct device dev; /* Generic device interface */

Index: linux/include/linux/pci_regs.h
===================================================================
--- linux.orig/include/linux/pci_regs.h 2008-01-23 10:14:14.000000000 +0800
+++ linux/include/linux/pci_regs.h 2008-01-23 10:14:46.000000000 +0800
@@ -395,9 +395,17 @@
#define PCI_EXP_DEVSTA_AUXPD 0x10 /* AUX Power Detected */
#define PCI_EXP_DEVSTA_TRPND 0x20 /* Transactions Pending */
#define PCI_EXP_LNKCAP 12 /* Link Capabilities */
+#define PCI_EXP_LNKCAP_ASPMS 0xc00 /* ASPM Support */
+#define PCI_EXP_LNKCAP_L0SEL 0x7000 /* L0s Exit Latency */
+#define PCI_EXP_LNKCAP_L1EL 0x38000 /* L1 Exit Latency */
+#define PCI_EXP_LNKCAP_CLKPM 0x40000 /* L1 Clock Power Management */
#define PCI_EXP_LNKCTL 16 /* Link Control */
+#define PCI_EXP_LNKCTL_RL 0x20 /* Retrain Link */
+#define PCI_EXP_LNKCTL_CCC 0x40 /* Common Clock COnfiguration */
#define PCI_EXP_LNKCTL_CLKREQ_EN 0x100 /* Enable clkreq */
#define PCI_EXP_LNKSTA 18 /* Link Status */
+#define PCI_EXP_LNKSTA_LT 0x800 /* Link Training */
+#define PCI_EXP_LNKSTA_SLC 0x1000 /* Slot Clock Configuration */
#define PCI_EXP_SLTCAP 20 /* Slot Capabilities */
#define PCI_EXP_SLTCTL 24 /* Slot Control */
#define PCI_EXP_SLTSTA 26 /* Slot Status */
Index: linux/drivers/pci/probe.c
===================================================================
--- linux.orig/drivers/pci/probe.c 2008-01-23 10:14:14.000000000 +0800
+++ linux/drivers/pci/probe.c 2008-01-23 10:14:46.000000000 +0800
@@ -9,6 +9,7 @@
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/cpumask.h>
+#include <linux/aspm.h>
#include "pci.h"

#define CARDBUS_LATENCY_TIMER 176 /* secondary latency timer */
@@ -1011,6 +1012,10 @@ int pci_scan_slot(struct pci_bus *bus, i
break;
}
}
+
+ if (bus->self)
+ pcie_aspm_init_link_state(bus->self);
+
return nr;
}

Index: linux/drivers/pci/remove.c
===================================================================
--- linux.orig/drivers/pci/remove.c 2008-01-23 10:14:14.000000000 +0800
+++ linux/drivers/pci/remove.c 2008-01-23 10:14:46.000000000 +0800
@@ -1,5 +1,6 @@
#include <linux/pci.h>
#include <linux/module.h>
+#include <linux/aspm.h>
#include "pci.h"

static void pci_free_resources(struct pci_dev *dev)
@@ -30,6 +31,9 @@ static void pci_stop_dev(struct pci_dev
dev->global_list.next = dev->global_list.prev = NULL;
up_write(&pci_bus_sem);
}
+
+ if (dev->bus->self)
+ pcie_aspm_exit_link_state(dev);
}

static void pci_destroy_dev(struct pci_dev *dev)
Index: linux/drivers/pci/pci.c
===================================================================
--- linux.orig/drivers/pci/pci.c 2008-01-23 10:14:14.000000000 +0800
+++ linux/drivers/pci/pci.c 2008-01-23 10:14:46.000000000 +0800
@@ -18,6 +18,7 @@
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/log2.h>
+#include <linux/aspm.h>
#include <asm/dma.h> /* isa_dma_bridge_buggy */
#include "pci.h"

@@ -501,6 +502,9 @@ pci_set_power_state(struct pci_dev *dev,
if (need_restore)
pci_restore_bars(dev);

+ if (dev->bus->self)
+ pcie_aspm_pm_state_change(dev->bus->self);
+
return 0;
}

Index: linux/drivers/pci/pci-sysfs.c
===================================================================
--- linux.orig/drivers/pci/pci-sysfs.c 2008-01-23 10:14:14.000000000 +0800
+++ linux/drivers/pci/pci-sysfs.c 2008-01-23 10:14:46.000000000 +0800
@@ -21,6 +21,7 @@
#include <linux/topology.h>
#include <linux/mm.h>
#include <linux/capability.h>
+#include <linux/aspm.h>
#include "pci.h"

static int sysfs_initialized; /* = 0 */
@@ -650,6 +651,8 @@ int __must_check pci_create_sysfs_dev_fi
if (pcibios_add_platform_entries(pdev))
goto err_rom_file;

+ pcie_aspm_create_sysfs_dev_files(pdev);
+
return 0;

err_rom_file:
@@ -679,6 +682,8 @@ void pci_remove_sysfs_dev_files(struct p
if (!sysfs_initialized)
return;

+ pcie_aspm_remove_sysfs_dev_files(pdev);
+
if (pdev->cfg_size < 4096)
sysfs_remove_bin_file(&pdev->dev.kobj, &pci_config_attr);
else



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