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path: root/drivers/pci/pcie
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Diffstat (limited to 'drivers/pci/pcie')
-rw-r--r--drivers/pci/pcie/ptm.c31
1 files changed, 29 insertions, 2 deletions
diff --git a/drivers/pci/pcie/ptm.c b/drivers/pci/pcie/ptm.c
index a14ac94b96dc..bab8ac63c4f3 100644
--- a/drivers/pci/pcie/ptm.c
+++ b/drivers/pci/pcie/ptm.c
@@ -19,13 +19,29 @@
static void pci_ptm_info(struct pci_dev *dev)
{
- dev_info(&dev->dev, "PTM enabled%s\n", dev->ptm_root ? " (root)" : "");
+ char clock_desc[8];
+
+ switch (dev->ptm_granularity) {
+ case 0:
+ snprintf(clock_desc, sizeof(clock_desc), "unknown");
+ break;
+ case 255:
+ snprintf(clock_desc, sizeof(clock_desc), ">254ns");
+ break;
+ default:
+ snprintf(clock_desc, sizeof(clock_desc), "%udns",
+ dev->ptm_granularity);
+ break;
+ }
+ dev_info(&dev->dev, "PTM enabled%s, %s granularity\n",
+ dev->ptm_root ? " (root)" : "", clock_desc);
}
void pci_ptm_init(struct pci_dev *dev)
{
int pos;
u32 cap, ctrl;
+ u8 local_clock;
struct pci_dev *ups;
if (!pci_is_pcie(dev))
@@ -45,6 +61,7 @@ void pci_ptm_init(struct pci_dev *dev)
return;
pci_read_config_dword(dev, pos + PCI_PTM_CAP, &cap);
+ local_clock = (cap & PCI_PTM_GRANULARITY_MASK) >> 8;
/*
* There's no point in enabling PTM unless it's enabled in the
@@ -55,14 +72,20 @@ void pci_ptm_init(struct pci_dev *dev)
ups = pci_upstream_bridge(dev);
if (ups && ups->ptm_enabled) {
ctrl = PCI_PTM_CTRL_ENABLE;
+ if (ups->ptm_granularity == 0)
+ dev->ptm_granularity = 0;
+ else if (ups->ptm_granularity > local_clock)
+ dev->ptm_granularity = ups->ptm_granularity;
} else {
if (cap & PCI_PTM_CAP_ROOT) {
ctrl = PCI_PTM_CTRL_ENABLE | PCI_PTM_CTRL_ROOT;
dev->ptm_root = 1;
+ dev->ptm_granularity = local_clock;
} else
return;
}
+ ctrl |= dev->ptm_granularity << 8;
pci_write_config_dword(dev, pos + PCI_PTM_CTRL, ctrl);
dev->ptm_enabled = 1;
@@ -98,18 +121,22 @@ int pci_enable_ptm(struct pci_dev *dev, u8 *granularity)
ups = pci_upstream_bridge(dev);
if (!ups || !ups->ptm_enabled)
return -EINVAL;
+
+ dev->ptm_granularity = ups->ptm_granularity;
} else if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) {
+ dev->ptm_granularity = 0;
} else
return -EINVAL;
ctrl = PCI_PTM_CTRL_ENABLE;
+ ctrl |= dev->ptm_granularity << 8;
pci_write_config_dword(dev, pos + PCI_PTM_CTRL, ctrl);
dev->ptm_enabled = 1;
pci_ptm_info(dev);
if (granularity)
- *granularity = 0;
+ *granularity = dev->ptm_granularity;
return 0;
}
EXPORT_SYMBOL(pci_enable_ptm);