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PCI: Remove unused Latency Tolerance Reporting support

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My philosophy is unused code is dead code.  And dead code is subject to bit
rot and is a likely source of bugs.  Use it or lose it.

This reverts 51c2e0a7e5 ("PCI: add latency tolerance reporting
enable/disable support"), removing these interfaces:

    pci_enable_ltr()
    pci_disable_ltr()
    pci_set_ltr()

[bhelgaas: split to separate patch, also remove prototypes from pci.h]
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: Jesse Barnes <jbarnes@virtuousgeek.org>
This commit is contained in:
Stephen Hemminger 2014-01-10 14:00:57 -07:00 committed by Bjorn Helgaas
parent b340cacc1b
commit 3ea8197e13
2 changed files with 0 additions and 127 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

123
drivers/pci/pci.c
View File

@ -2223,129 +2223,6 @@ void pci_disable_obff(struct pci_dev *dev)
}
EXPORT_SYMBOL(pci_disable_obff);
/**
* pci_ltr_supported - check whether a device supports LTR
* @dev: PCI device
*
* RETURNS:
* True if @dev supports latency tolerance reporting, false otherwise.
*/
static bool pci_ltr_supported(struct pci_dev *dev)
{
u32 cap;
pcie_capability_read_dword(dev, PCI_EXP_DEVCAP2, &cap);
return cap & PCI_EXP_DEVCAP2_LTR;
}
/**
* pci_enable_ltr - enable latency tolerance reporting
* @dev: PCI device
*
* Enable LTR on @dev if possible, which means enabling it first on
* upstream ports.
*
* RETURNS:
* Zero on success, errno on failure.
*/
int pci_enable_ltr(struct pci_dev *dev)
{
int ret;
/* Only primary function can enable/disable LTR */
if (PCI_FUNC(dev->devfn) != 0)
return -EINVAL;
if (!pci_ltr_supported(dev))
return -ENOTSUPP;
/* Enable upstream ports first */
if (dev->bus->self) {
ret = pci_enable_ltr(dev->bus->self);
if (ret)
return ret;
}
return pcie_capability_set_word(dev, PCI_EXP_DEVCTL2,
PCI_EXP_DEVCTL2_LTR_EN);
}
EXPORT_SYMBOL(pci_enable_ltr);
/**
* pci_disable_ltr - disable latency tolerance reporting
* @dev: PCI device
*/
void pci_disable_ltr(struct pci_dev *dev)
{
/* Only primary function can enable/disable LTR */
if (PCI_FUNC(dev->devfn) != 0)
return;
if (!pci_ltr_supported(dev))
return;
pcie_capability_clear_word(dev, PCI_EXP_DEVCTL2,
PCI_EXP_DEVCTL2_LTR_EN);
}
EXPORT_SYMBOL(pci_disable_ltr);
static int __pci_ltr_scale(int *val)
{
int scale = 0;
while (*val > 1023) {
*val = (*val + 31) / 32;
scale++;
}
return scale;
}
/**
* pci_set_ltr - set LTR latency values
* @dev: PCI device
* @snoop_lat_ns: snoop latency in nanoseconds
* @nosnoop_lat_ns: nosnoop latency in nanoseconds
*
* Figure out the scale and set the LTR values accordingly.
*/
int pci_set_ltr(struct pci_dev *dev, int snoop_lat_ns, int nosnoop_lat_ns)
{
int pos, ret, snoop_scale, nosnoop_scale;
u16 val;
if (!pci_ltr_supported(dev))
return -ENOTSUPP;
snoop_scale = __pci_ltr_scale(&snoop_lat_ns);
nosnoop_scale = __pci_ltr_scale(&nosnoop_lat_ns);
if (snoop_lat_ns > PCI_LTR_VALUE_MASK ||
nosnoop_lat_ns > PCI_LTR_VALUE_MASK)
return -EINVAL;
if ((snoop_scale > (PCI_LTR_SCALE_MASK >> PCI_LTR_SCALE_SHIFT)) ||
(nosnoop_scale > (PCI_LTR_SCALE_MASK >> PCI_LTR_SCALE_SHIFT)))
return -EINVAL;
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_LTR);
if (!pos)
return -ENOTSUPP;
val = (snoop_scale << PCI_LTR_SCALE_SHIFT) | snoop_lat_ns;
ret = pci_write_config_word(dev, pos + PCI_LTR_MAX_SNOOP_LAT, val);
if (ret != 4)
return -EIO;
val = (nosnoop_scale << PCI_LTR_SCALE_SHIFT) | nosnoop_lat_ns;
ret = pci_write_config_word(dev, pos + PCI_LTR_MAX_NOSNOOP_LAT, val);
if (ret != 4)
return -EIO;
return 0;
}
EXPORT_SYMBOL(pci_set_ltr);
static int pci_acs_enable;
/**

4
include/linux/pci.h
View File

@ -1009,10 +1009,6 @@ enum pci_obff_signal_type {
int pci_enable_obff(struct pci_dev *dev, enum pci_obff_signal_type);
void pci_disable_obff(struct pci_dev *dev);
int pci_enable_ltr(struct pci_dev *dev);
void pci_disable_ltr(struct pci_dev *dev);
int pci_set_ltr(struct pci_dev *dev, int snoop_lat_ns, int nosnoop_lat_ns);
/* For use by arch with custom probe code */
void set_pcie_port_type(struct pci_dev *pdev);
void set_pcie_hotplug_bridge(struct pci_dev *pdev);