From c320b976d7837c561ce4aa49dfe0a64f0e527ce4 Mon Sep 17 00:00:00 2001 From: Joerg Roedel Date: Tue, 27 Sep 2011 15:57:15 +0200 Subject: 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 Signed-off-by: Joerg Roedel Signed-off-by: Jesse Barnes --- drivers/pci/Kconfig | 9 +++ drivers/pci/ats.c | 167 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 176 insertions(+) (limited to 'drivers/pci') diff --git a/drivers/pci/Kconfig b/drivers/pci/Kconfig index 1d8ce8395861..fb1e9707f91e 100644 --- a/drivers/pci/Kconfig +++ b/drivers/pci/Kconfig @@ -85,6 +85,15 @@ config PCI_IOV If unsure, say N. +config PCI_PRI + bool "PCI PRI support" + select PCI_ATS + help + PRI is the PCI Page Request Interface. It allows PCI devices that are + behind an IOMMU to recover from page faults. + + If unsure, say N. + config PCI_IOAPIC bool depends on PCI diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c index 5ceff3e16e1b..bf892a025d4f 100644 --- a/drivers/pci/ats.c +++ b/drivers/pci/ats.c @@ -2,9 +2,11 @@ * drivers/pci/ats.c * * Copyright (C) 2009 Intel Corporation, Yu Zhao + * 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 */ #include @@ -156,3 +158,168 @@ int pci_ats_queue_depth(struct pci_dev *dev) 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 */ -- cgit v1.2.3