PCI: Simplify PCI device PM code

If the offset of PCI device's PM capability in its configuration space,
the mask of states that the device supports PME# from and the D1 and D2
support bits are cached in the corresponding struct pci_dev, the PCI
device PM code can be simplified quite a bit.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

3 files changed, 60 insertions, 67 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 1b0ec45e9934..e632a58ba5d0 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -419,7 +419,6 @@ static inline int platform_pci_sleep_wake(struct pci_dev *dev, bool enable)
  * pci_raw_set_power_state - Use PCI PM registers to set the power state of
  *                           given PCI device
  * @dev: PCI device to handle.
- * @pm: PCI PM capability offset of the device.
  * @state: PCI power state (D0, D1, D2, D3hot) to put the device into.
  *
  * RETURN VALUE:
@@ -430,12 +429,12 @@ static inline int platform_pci_sleep_wake(struct pci_dev *dev, bool enable)
  * 0 if device's power state has been successfully changed.
  */
 static int
-pci_raw_set_power_state(struct pci_dev *dev, int pm, pci_power_t state)
+pci_raw_set_power_state(struct pci_dev *dev, pci_power_t state)
 {
-        u16 pmcsr, pmc;
+        u16 pmcsr;
         bool need_restore = false;
 
-        if (!pm)
+        if (!dev->pm_cap)
                 return -EIO;
 
         if (state < PCI_D0 || state > PCI_D3hot)
@@ -455,20 +454,12 @@ pci_raw_set_power_state(struct pci_dev *dev, int pm, pci_power_t state)
                 return -EINVAL;
         }
 
-        pci_read_config_word(dev, pm + PCI_PM_PMC, &pmc);
-
-        if ((pmc & PCI_PM_CAP_VER_MASK) > 3) {
-                dev_err(&dev->dev, "unsupported PM cap regs version (%u)\n",
-                        pmc & PCI_PM_CAP_VER_MASK);
-                return -EIO;
-        }
-
         /* check if this device supports the desired state */
-        if ((state == PCI_D1 && !(pmc & PCI_PM_CAP_D1))
-           || (state == PCI_D2 && !(pmc & PCI_PM_CAP_D2)))
+        if ((state == PCI_D1 && !dev->d1_support)
+           || (state == PCI_D2 && !dev->d2_support))
                 return -EIO;
 
-        pci_read_config_word(dev, pm + PCI_PM_CTRL, &pmcsr);
+        pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
 
         /* If we're (effectively) in D3, force entire word to 0.
          * This doesn't affect PME_Status, disables PME_En, and
@@ -492,7 +483,7 @@ pci_raw_set_power_state(struct pci_dev *dev, int pm, pci_power_t state)
         }
 
         /* enter specified state */
-        pci_write_config_word(dev, pm + PCI_PM_CTRL, pmcsr);
+        pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr);
 
         /* Mandatory power management transition delays */
         /* see PCI PM 1.1 5.6.1 table 18 */
@@ -528,14 +519,13 @@ pci_raw_set_power_state(struct pci_dev *dev, int pm, pci_power_t state)
  * pci_update_current_state - Read PCI power state of given device from its
  *                            PCI PM registers and cache it
  * @dev: PCI device to handle.
- * @pm: PCI PM capability offset of the device.
  */
-static void pci_update_current_state(struct pci_dev *dev, int pm)
+static void pci_update_current_state(struct pci_dev *dev)
 {
-        if (pm) {
+        if (dev->pm_cap) {
                 u16 pmcsr;
 
-                pci_read_config_word(dev, pm + PCI_PM_CTRL, &pmcsr);
+                pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
                 dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK);
         }
 }
@@ -557,7 +547,7 @@ static void pci_update_current_state(struct pci_dev *dev, int pm)
  */
 int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
 {
-        int pm, error;
+        int error;
 
         /* bound the state we're entering */
         if (state > PCI_D3hot)
@@ -572,9 +562,6 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
                  */
                 return 0;
 
-        /* Find PCI PM capability in the list */
-        pm = pci_find_capability(dev, PCI_CAP_ID_PM);
-
         if (state == PCI_D0 && platform_pci_power_manageable(dev)) {
                 /*
                  * Allow the platform to change the state, for example via ACPI
@@ -582,16 +569,16 @@ int pci_set_power_state(struct pci_dev *dev, pci_power_t state)
                  */
                 int ret = platform_pci_set_power_state(dev, PCI_D0);
                 if (!ret)
-                        pci_update_current_state(dev, pm);
+                        pci_update_current_state(dev);
         }
 
-        error = pci_raw_set_power_state(dev, pm, state);
+        error = pci_raw_set_power_state(dev, state);
 
         if (state > PCI_D0 && platform_pci_power_manageable(dev)) {
                 /* Allow the platform to finalize the transition */
                 int ret = platform_pci_set_power_state(dev, state);
                 if (!ret) {
-                        pci_update_current_state(dev, pm);
+                        pci_update_current_state(dev);
                         error = 0;
                 }
         }
@@ -1050,48 +1037,38 @@ int pci_set_pcie_reset_state(struct pci_dev *dev, enum pcie_reset_state state)
 /**
  * pci_pme_capable - check the capability of PCI device to generate PME#
  * @dev: PCI device to handle.
- * @pm: PCI PM capability offset of the device.
  * @state: PCI state from which device will issue PME#.
  */
-static bool pci_pme_capable(struct pci_dev *dev, int pm, pci_power_t state)
+static bool pci_pme_capable(struct pci_dev *dev, pci_power_t state)
 {
-        u16 pmc;
-
-        if (!pm)
+        if (!dev->pm_cap)
                 return false;
 
-        /* Check device's ability to generate PME# from given state */
-        pci_read_config_word(dev, pm + PCI_PM_PMC, &pmc);
-
-        pmc &= PCI_PM_CAP_PME_MASK;
-        pmc >>= ffs(PCI_PM_CAP_PME_MASK) - 1;   /* First bit of mask */
-
-        return !!(pmc & (1 << state));
+        return !!(dev->pme_support & (1 << state));
 }
 
 /**
  * pci_pme_active - enable or disable PCI device's PME# function
  * @dev: PCI device to handle.
- * @pm: PCI PM capability offset of the device.
  * @enable: 'true' to enable PME# generation; 'false' to disable it.
  *
  * The caller must verify that the device is capable of generating PME# before
  * calling this function with @enable equal to 'true'.
  */
-static void pci_pme_active(struct pci_dev *dev, int pm, bool enable)
+static void pci_pme_active(struct pci_dev *dev, bool enable)
 {
         u16 pmcsr;
 
-        if (!pm)
+        if (!dev->pm_cap)
                 return;
 
-        pci_read_config_word(dev, pm + PCI_PM_CTRL, &pmcsr);
+        pci_read_config_word(dev, dev->pm_cap + PCI_PM_CTRL, &pmcsr);
         /* Clear PME_Status by writing 1 to it and enable PME# */
         pmcsr |= PCI_PM_CTRL_PME_STATUS | PCI_PM_CTRL_PME_ENABLE;
         if (!enable)
                 pmcsr &= ~PCI_PM_CTRL_PME_ENABLE;
 
-        pci_write_config_word(dev, pm + PCI_PM_CTRL, pmcsr);
+        pci_write_config_word(dev, dev->pm_cap + PCI_PM_CTRL, pmcsr);
 
         dev_printk(KERN_INFO, &dev->dev, "PME# %s\n",
                         enable ? "enabled" : "disabled");
@@ -1118,7 +1095,6 @@ static void pci_pme_active(struct pci_dev *dev, int pm, bool enable)
  */
 int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
 {
-        int pm;
         int error = 0;
         bool pme_done = false;
 
@@ -1134,9 +1110,8 @@ int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
         if (!enable && platform_pci_can_wakeup(dev))
                 error = platform_pci_sleep_wake(dev, false);
 
-        pm = pci_find_capability(dev, PCI_CAP_ID_PM);
-        if (!enable || pci_pme_capable(dev, pm, state)) {
-                pci_pme_active(dev, pm, enable);
+        if (!enable || pci_pme_capable(dev, state)) {
+                pci_pme_active(dev, enable);
                 pme_done = true;
         }
 
@@ -1158,7 +1133,6 @@ int pci_enable_wake(struct pci_dev *dev, pci_power_t state, int enable)
 int pci_prepare_to_sleep(struct pci_dev *dev)
 {
         pci_power_t target_state = PCI_D3hot;
-        int pm = pci_find_capability(dev, PCI_CAP_ID_PM);
         int error;
 
         if (platform_pci_power_manageable(dev)) {
@@ -1186,23 +1160,14 @@ int pci_prepare_to_sleep(struct pci_dev *dev)
                  * wake-up events, make it the target state and enable device
                  * to generate PME#.
                  */
-                u16 pmc;
-
-                if (!pm)
+                if (!dev->pm_cap)
                         return -EIO;
 
-                pci_read_config_word(dev, pm + PCI_PM_PMC, &pmc);
-                if (pmc & PCI_PM_CAP_PME_MASK) {
-                        if (!(pmc & PCI_PM_CAP_PME_D3)) {
-                                /* Device cannot generate PME# from D3_hot */
-                                if (pmc & PCI_PM_CAP_PME_D2)
-                                        target_state = PCI_D2;
-                                else if (pmc & PCI_PM_CAP_PME_D1)
-                                        target_state = PCI_D1;
-                                else
-                                        target_state = PCI_D0;
-                        }
-                        pci_pme_active(dev, pm, true);
+                if (dev->pme_support) {
+                        while (target_state
+                              && !(dev->pme_support & (1 << target_state)))
+                                target_state--;
+                        pci_pme_active(dev, true);
                 }
         }
 
@@ -1236,6 +1201,8 @@ void pci_pm_init(struct pci_dev *dev)
         int pm;
         u16 pmc;
 
+        dev->pm_cap = 0;
+
         /* find PCI PM capability in list */
         pm = pci_find_capability(dev, PCI_CAP_ID_PM);
         if (!pm)
@@ -1249,7 +1216,23 @@ void pci_pm_init(struct pci_dev *dev)
                 return;
         }
 
-        if (pmc & PCI_PM_CAP_PME_MASK) {
+        dev->pm_cap = pm;
+
+        dev->d1_support = false;
+        dev->d2_support = false;
+        if (!pci_no_d1d2(dev)) {
+                if (pmc & PCI_PM_CAP_D1) {
+                        dev_printk(KERN_DEBUG, &dev->dev, "supports D1\n");
+                        dev->d1_support = true;
+                }
+                if (pmc & PCI_PM_CAP_D2) {
+                        dev_printk(KERN_DEBUG, &dev->dev, "supports D2\n");
+                        dev->d2_support = true;
+                }
+        }
+
+        pmc &= PCI_PM_CAP_PME_MASK;
+        if (pmc) {
                 dev_printk(KERN_INFO, &dev->dev,
                         "PME# supported from%s%s%s%s%s\n",
                         (pmc & PCI_PM_CAP_PME_D0) ? " D0" : "",
@@ -1257,6 +1240,7 @@ void pci_pm_init(struct pci_dev *dev)
                         (pmc & PCI_PM_CAP_PME_D2) ? " D2" : "",
                         (pmc & PCI_PM_CAP_PME_D3) ? " D3hot" : "",
                         (pmc & PCI_PM_CAP_PME_D3cold) ? " D3cold" : "");
+                dev->pme_support = pmc >> PCI_PM_CAP_PME_SHIFT;
                 /*
                  * Make device's PM flags reflect the wake-up capability, but
                  * let the user space enable it to wake up the system as needed.
@@ -1264,7 +1248,9 @@ void pci_pm_init(struct pci_dev *dev)
                 device_set_wakeup_capable(&dev->dev, true);
                 device_set_wakeup_enable(&dev->dev, false);
                 /* Disable the PME# generation functionality */
-                pci_pme_active(dev, pm, false);
+                pci_pme_active(dev, false);
+        } else {
+                dev->pme_support = 0;
         }
 }
 
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 52ac06dcce98..68a29f0f2748 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -177,6 +177,13 @@ struct pci_dev {
         pci_power_t     current_state;  /* Current operating state. In ACPI-speak,
                                            this is D0-D3, D0 being fully functional,
                                            and D3 being off. */
+        int             pm_cap;         /* PM capability offset in the
+                                           configuration space */
+        unsigned int    pme_support:5;  /* Bitmask of states from which PME#
+                                           can be generated */
+        unsigned int    d1_support:1;   /* Low power state D1 is supported */
+        unsigned int    d2_support:1;   /* Low power state D2 is supported */
+        unsigned int    no_d1d2:1;      /* Only allow D0 and D3 */
 
 #ifdef CONFIG_PCIEASPM
         struct pcie_link_state  *link_state;    /* ASPM link state. */
@@ -201,7 +208,6 @@ struct pci_dev {
         unsigned int    is_added:1;
         unsigned int    is_busmaster:1; /* device is busmaster */
         unsigned int    no_msi:1;       /* device may not use msi */
-        unsigned int    no_d1d2:1;   /* only allow d0 or d3 */
         unsigned int    block_ucfg_access:1;    /* userspace config space access is blocked */
         unsigned int    broken_parity_status:1; /* Device generates false positive parity */
         unsigned int    msi_enabled:1;
diff --git a/include/linux/pci_regs.h b/include/linux/pci_regs.h
index c0c1223c9194..19958b929905 100644
--- a/include/linux/pci_regs.h
+++ b/include/linux/pci_regs.h
@@ -231,6 +231,7 @@
 #define  PCI_PM_CAP_PME_D2      0x2000  /* PME# from D2 */
 #define  PCI_PM_CAP_PME_D3      0x4000  /* PME# from D3 (hot) */
 #define  PCI_PM_CAP_PME_D3cold  0x8000  /* PME# from D3 (cold) */
+#define  PCI_PM_CAP_PME_SHIFT   11      /* Start of the PME Mask in PMC */
 #define PCI_PM_CTRL             4       /* PM control and status register */
 #define  PCI_PM_CTRL_STATE_MASK 0x0003  /* Current power state (D0 to D3) */
 #define  PCI_PM_CTRL_NO_SOFT_RESET      0x0004  /* No reset for D3hot->D0 */