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linux-hardened/drivers/pci/ats.c
Joerg Roedel c320b976d7 PCI: Add implementation for PRI capability 
Implement the necessary functions to handle PRI capabilities
on PCIe devices. With PRI devices behind an IOMMU can signal
page fault conditions to software and recover from such
faults.

Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
2011-10-14 09:05:34 -07:00

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/*
* drivers/pci/ats.c
*
* Copyright (C) 2009 Intel Corporation, Yu Zhao <yu.zhao@intel.com>
* Copyright (C) 2011 Advanced Micro Devices,
*
* PCI Express I/O Virtualization (IOV) support.
* Address Translation Service 1.0
* Page Request Interface added by Joerg Roedel <joerg.roedel@amd.com>
*/
#include <linux/pci-ats.h>
#include <linux/pci.h>
#include "pci.h"
static int ats_alloc_one(struct pci_dev *dev, int ps)
{
int pos;
u16 cap;
struct pci_ats *ats;
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
if (!pos)
return -ENODEV;
ats = kzalloc(sizeof(*ats), GFP_KERNEL);
if (!ats)
return -ENOMEM;
ats->pos = pos;
ats->stu = ps;
pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
ats->qdep = PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
PCI_ATS_MAX_QDEP;
dev->ats = ats;
return 0;
}
static void ats_free_one(struct pci_dev *dev)
{
kfree(dev->ats);
dev->ats = NULL;
}
/**
* pci_enable_ats - enable the ATS capability
* @dev: the PCI device
* @ps: the IOMMU page shift
*
* Returns 0 on success, or negative on failure.
*/
int pci_enable_ats(struct pci_dev *dev, int ps)
{
int rc;
u16 ctrl;
BUG_ON(dev->ats && dev->ats->is_enabled);
if (ps < PCI_ATS_MIN_STU)
return -EINVAL;
if (dev->is_physfn || dev->is_virtfn) {
struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;
mutex_lock(&pdev->sriov->lock);
if (pdev->ats)
rc = pdev->ats->stu == ps ? 0 : -EINVAL;
else
rc = ats_alloc_one(pdev, ps);
if (!rc)
pdev->ats->ref_cnt++;
mutex_unlock(&pdev->sriov->lock);
if (rc)
return rc;
}
if (!dev->is_physfn) {
rc = ats_alloc_one(dev, ps);
if (rc)
return rc;
}
ctrl = PCI_ATS_CTRL_ENABLE;
if (!dev->is_virtfn)
ctrl |= PCI_ATS_CTRL_STU(ps - PCI_ATS_MIN_STU);
pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
dev->ats->is_enabled = 1;
return 0;
}
EXPORT_SYMBOL_GPL(pci_enable_ats);
/**
* pci_disable_ats - disable the ATS capability
* @dev: the PCI device
*/
void pci_disable_ats(struct pci_dev *dev)
{
u16 ctrl;
BUG_ON(!dev->ats || !dev->ats->is_enabled);
pci_read_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, &ctrl);
ctrl &= ~PCI_ATS_CTRL_ENABLE;
pci_write_config_word(dev, dev->ats->pos + PCI_ATS_CTRL, ctrl);
dev->ats->is_enabled = 0;
if (dev->is_physfn || dev->is_virtfn) {
struct pci_dev *pdev = dev->is_physfn ? dev : dev->physfn;
mutex_lock(&pdev->sriov->lock);
pdev->ats->ref_cnt--;
if (!pdev->ats->ref_cnt)
ats_free_one(pdev);
mutex_unlock(&pdev->sriov->lock);
}
if (!dev->is_physfn)
ats_free_one(dev);
}
EXPORT_SYMBOL_GPL(pci_disable_ats);
/**
* pci_ats_queue_depth - query the ATS Invalidate Queue Depth
* @dev: the PCI device
*
* Returns the queue depth on success, or negative on failure.
*
* The ATS spec uses 0 in the Invalidate Queue Depth field to
* indicate that the function can accept 32 Invalidate Request.
* But here we use the `real' values (i.e. 1~32) for the Queue
* Depth; and 0 indicates the function shares the Queue with
* other functions (doesn't exclusively own a Queue).
*/
int pci_ats_queue_depth(struct pci_dev *dev)
{
int pos;
u16 cap;
if (dev->is_virtfn)
return 0;
if (dev->ats)
return dev->ats->qdep;
pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ATS);
if (!pos)
return -ENODEV;
pci_read_config_word(dev, pos + PCI_ATS_CAP, &cap);
return PCI_ATS_CAP_QDEP(cap) ? PCI_ATS_CAP_QDEP(cap) :
PCI_ATS_MAX_QDEP;
}
EXPORT_SYMBOL_GPL(pci_ats_queue_depth);
#ifdef CONFIG_PCI_PRI
/**
* pci_enable_pri - Enable PRI capability
* @ pdev: PCI device structure
*
* Returns 0 on success, negative value on error
*/
int pci_enable_pri(struct pci_dev *pdev, u32 reqs)
{
u16 control, status;
u32 max_requests;
int pos;
pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
if (!pos)
return -EINVAL;
pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
pci_read_config_word(pdev, pos + PCI_PRI_STATUS_OFF, &status);
if ((control & PCI_PRI_ENABLE) || !(status & PCI_PRI_STATUS_STOPPED))
return -EBUSY;
pci_read_config_dword(pdev, pos + PCI_PRI_MAX_REQ_OFF, &max_requests);
reqs = min(max_requests, reqs);
pci_write_config_dword(pdev, pos + PCI_PRI_ALLOC_REQ_OFF, reqs);
control |= PCI_PRI_ENABLE;
pci_write_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, control);
return 0;
}
EXPORT_SYMBOL_GPL(pci_enable_pri);
/**
* pci_disable_pri - Disable PRI capability
* @pdev: PCI device structure
*
* Only clears the enabled-bit, regardless of its former value
*/
void pci_disable_pri(struct pci_dev *pdev)
{
u16 control;
int pos;
pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
if (!pos)
return;
pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
control &= ~PCI_PRI_ENABLE;
pci_write_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, control);
}
EXPORT_SYMBOL_GPL(pci_disable_pri);
/**
* pci_pri_enabled - Checks if PRI capability is enabled
* @pdev: PCI device structure
*
* Returns true if PRI is enabled on the device, false otherwise
*/
bool pci_pri_enabled(struct pci_dev *pdev)
{
u16 control;
int pos;
pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
if (!pos)
return false;
pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
return (control & PCI_PRI_ENABLE) ? true : false;
}
EXPORT_SYMBOL_GPL(pci_pri_enabled);
/**
* pci_reset_pri - Resets device's PRI state
* @pdev: PCI device structure
*
* The PRI capability must be disabled before this function is called.
* Returns 0 on success, negative value on error.
*/
int pci_reset_pri(struct pci_dev *pdev)
{
u16 control;
int pos;
pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
if (!pos)
return -EINVAL;
pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
if (control & PCI_PRI_ENABLE)
return -EBUSY;
control |= PCI_PRI_RESET;
pci_write_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, control);
return 0;
}
EXPORT_SYMBOL_GPL(pci_reset_pri);
/**
* pci_pri_stopped - Checks whether the PRI capability is stopped
* @pdev: PCI device structure
*
* Returns true if the PRI capability on the device is disabled and the
* device has no outstanding PRI requests, false otherwise. The device
* indicates this via the STOPPED bit in the status register of the
* capability.
* The device internal state can be cleared by resetting the PRI state
* with pci_reset_pri(). This can force the capability into the STOPPED
* state.
*/
bool pci_pri_stopped(struct pci_dev *pdev)
{
u16 control, status;
int pos;
pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
if (!pos)
return true;
pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
pci_read_config_word(pdev, pos + PCI_PRI_STATUS_OFF, &status);
if (control & PCI_PRI_ENABLE)
return false;
return (status & PCI_PRI_STATUS_STOPPED) ? true : false;
}
EXPORT_SYMBOL_GPL(pci_pri_stopped);
/**
* pci_pri_status - Request PRI status of a device
* @pdev: PCI device structure
*
* Returns negative value on failure, status on success. The status can
* be checked against status-bits. Supported bits are currently:
* PCI_PRI_STATUS_RF: Response failure
* PCI_PRI_STATUS_UPRGI: Unexpected Page Request Group Index
* PCI_PRI_STATUS_STOPPED: PRI has stopped
*/
int pci_pri_status(struct pci_dev *pdev)
{
u16 status, control;
int pos;
pos = pci_find_ext_capability(pdev, PCI_PRI_CAP);
if (!pos)
return -EINVAL;
pci_read_config_word(pdev, pos + PCI_PRI_CONTROL_OFF, &control);
pci_read_config_word(pdev, pos + PCI_PRI_STATUS_OFF, &status);
/* Stopped bit is undefined when enable == 1, so clear it */
if (control & PCI_PRI_ENABLE)
status &= ~PCI_PRI_STATUS_STOPPED;
return status;
}
EXPORT_SYMBOL_GPL(pci_pri_status);
#endif /* CONFIG_PCI_PRI */
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