[RFC][PATCH 2/6] PCI PM: capability probing and setup
From: Adam Belay (abelay_at_novell.com)
Date: 11/16/05
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To: Linux-pm mailing list <linux-pm@lists.osdl.org>, Greg KH <gregkh@suse.de> Date: Tue, 15 Nov 2005 22:31:17 -0500
This patch updates the PCI subsystem to probe the PCI capability
registers in one pass. This data is stored in "struct pci_dev_pm". As
a result, we can avoid having to redetect PCI PM support in every PM
related call. Also, we don't have to access PCI config space as often.
"struct pci_dev_pm" will likely be expanded to include PM accounting
data in the near future.
--- a/drivers/pci/pm.c 2005-11-07 08:08:00.000000000 -0500
+++ b/drivers/pci/pm.c 2005-11-07 08:09:11.000000000 -0500
@@ -294,3 +294,60 @@
}
EXPORT_SYMBOL(pci_enable_wake);
+
+
+/*
+ * PCI PM capability detection and setup
+ */
+
+int pci_setup_device_pm(struct pci_dev *dev)
+{
+ int pm;
+ u16 pmcsr, pmc;
+ struct pci_dev_pm *pm_data;
+
+ pm = pci_find_capability(dev, PCI_CAP_ID_PM);
+ if (!pm) {
+ dev->current_state = PCI_D0;
+ return 0;
+ }
+
+ pci_read_config_word(dev,pm + PCI_PM_PMC,&pmc);
+
+ if ((pmc & PCI_PM_CAP_VER_MASK) > 3) {
+ printk(KERN_DEBUG
+ "PCI: %s has unsupported PM cap regs version (%u)\n",
+ pci_name(dev), pmc & PCI_PM_CAP_VER_MASK);
+ return -EIO;
+ }
+
+ dev->pm = pm_data = kmalloc(sizeof(struct pci_dev_pm), GFP_KERNEL);
+ if (!pm_data)
+ return -ENOMEM;
+
+ memset(pm_data, 0, sizeof(struct pci_dev_pm));
+
+ pm_data->pm_offset = pm;
+
+ /* determine supported device states */
+ /* all PM capable devices support at least D0 and D3 */
+ pm_data->state_mask |= ((1 << PCI_D0) | (1 << PCI_D3hot));
+ if (pmc & PCI_PM_CAP_D1)
+ pm_data->state_mask |= (1 << PCI_D1);
+ if (pmc & PCI_PM_CAP_D2)
+ pm_data->state_mask |= (1 << PCI_D2);
+
+ /* PME capabilities */
+ pm_data->pme_mask = ((pmc & PCI_PM_CAP_PME_MASK)
+ >> (ffs(PCI_PM_CAP_PME_MASK) - 1));
+
+ pci_read_config_word(dev, pm + PCI_PM_CTRL, &pmcsr);
+
+ /* device context retention */
+ pm_data->dsi = (pmc & PCI_PM_CAP_DSI) ? 1 : 0;
+ pm_data->no_soft_reset = (pmcsr & PCI_PM_CTRL_NO_SOFT_RESET) ? 1 : 0;
+
+ dev->current_state = (pmcsr & PCI_PM_CTRL_STATE_MASK);
+
+ return 0;
+}
--- a/drivers/pci/probe.c 2005-11-07 08:08:00.000000000 -0500
+++ b/drivers/pci/probe.c 2005-11-07 08:05:10.000000000 -0500
@@ -601,8 +601,7 @@
pr_debug("PCI: Found %s [%04x/%04x] %06x %02x\n", pci_name(dev),
dev->vendor, dev->device, class, dev->hdr_type);
- /* "Unknown power state" */
- dev->current_state = PCI_UNKNOWN;
+ pci_setup_device_pm(dev);
/* Early fixups, before probing the BARs */
pci_fixup_device(pci_fixup_early, dev);
--- a/include/linux/pci.h 2005-11-07 08:08:00.000000000 -0500
+++ b/include/linux/pci.h 2005-11-07 08:02:55.000000000 -0500
@@ -68,6 +68,18 @@
#define DEVICE_COUNT_COMPATIBLE 4
#define DEVICE_COUNT_RESOURCE 12
+struct pci_dev_pm {
+ unsigned int pm_offset; /* the PCI PM capability offset */
+
+ unsigned int dsi:1; /* vendor-specific initialization needed
+ after a reset */
+ unsigned int no_soft_reset:1; /* PCI config context retained when
+ going from D3_hot to D0 */
+
+ unsigned char state_mask; /* a mask of supported power states */
+ unsigned char pme_mask; /* a mask of power states that allow #PME */
+};
+
typedef int __bitwise pci_power_t;
#define PCI_D0 ((pci_power_t __force) 0)
@@ -78,6 +90,12 @@
#define PCI_UNKNOWN ((pci_power_t __force) 5)
#define PCI_POWER_ERROR ((pci_power_t __force) -1)
+#define PCI_PME_D0 0x01;
+#define PCI_PME_D1 0x02;
+#define PCI_PME_D2 0x04;
+#define PCI_PME_D3hot 0x08;
+#define PCI_PME_D3cold 0x10;
+
/*
* The pci_dev structure is used to describe PCI devices.
*/
@@ -106,6 +124,7 @@
this if your device has broken DMA
or supports 64-bit transfers. */
+ struct pci_dev_pm *pm; /* power management information */
pci_power_t current_state; /* Current operating state. In ACPI-speak,
this is D0-D3, D0 being fully functional,
and D3 being off. */
-
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- Previous message: Adam Belay: "[RFC][PATCH 3/6] PCI PM: update pci_set_power_state()"
- Next in thread: Greg KH: "Re: [RFC][PATCH 2/6] PCI PM: capability probing and setup"
- Reply: Greg KH: "Re: [RFC][PATCH 2/6] PCI PM: capability probing and setup"
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