/* SPDX-License-Identifier: GPL-2.0 */
/*
* Gasket Page Table functionality. This file describes the address
* translation/paging functionality supported by the Gasket driver framework.
* As much as possible, internal details are hidden to simplify use -
* all calls are thread-safe (protected by an internal mutex) except where
* indicated otherwise.
*
* Copyright (C) 2018 Google, Inc.
*/
#ifndef __GASKET_PAGE_TABLE_H__
#define __GASKET_PAGE_TABLE_H__
#include <linux/pci.h>
#include <linux/types.h>
#include "gasket_constants.h"
#include "gasket_core.h"
/*
* Structure used for managing address translation on a device. All details are
* internal to the implementation.
*/
struct gasket_page_table;
/*
* Allocate and init address translation data.
* @ppage_table: Pointer to Gasket page table pointer. Set by this call.
* @att_base_reg: [Mapped] pointer to the first entry in the device's address
* translation table.
* @extended_offset_reg: [Mapped] pointer to the device's register containing
* the starting index of the extended translation table.
* @extended_bit_location: The index of the bit indicating whether an address
* is extended.
* @total_entries: The total number of entries in the device's address
* translation table.
* @device: Device structure for the underlying device. Only used for logging.
* @pci_dev: PCI system descriptor for the underlying device.
* whether the driver will supply its own.
*
* Description: Allocates and initializes data to track address translation -
* simple and extended page table metadata. Initially, the page table is
* partitioned such that all addresses are "simple" (single-level lookup).
* gasket_partition_page_table can be called to change this paritioning.
*
* Returns 0 on success, a negative error code otherwise.
*/
int gasket_page_table_init(struct gasket_page_table **ppg_tbl,
const struct gasket_bar_data *bar_data,
const struct gasket_page_table_config *page_table_config,
struct device *device, struct pci_dev *pci_dev);
/*
* Deallocate and cleanup page table data.
* @page_table: Gasket page table pointer.
*
* Description: The inverse of gasket_init; frees page_table and its contained
* elements.
*
* Because this call destroys the page table, it cannot be
* thread-safe (mutex-protected)!
*/
void gasket_page_table_cleanup(struct gasket_page_table *page_table);
/*
* Sets the size of the simple page table.
* @page_table: Gasket page table pointer.
* @num_simple_entries: Desired size of the simple page table (in entries).
*
* Description: gasket_partition_page_table checks to see if the simple page
* size can be changed (i.e., if there are no active extended
* mappings in the new simple size range), and, if so,
* sets the new simple and extended page table sizes.
*
* Returns 0 if successful, or non-zero if the page table entries
* are not free.
*/
int gasket_page_table_partition(struct gasket_page_table *page_table,
uint num_simple_entries);
/*
* Get and map [host] user space pages into device memory.
* @page_table: Gasket page table pointer.
* @host_addr: Starting host virtual memory address of the pages.
* @dev_addr: Starting device address of the pages.
* @num_pages: Number of [4kB] pages to map.
*
* Description: Maps the "num_pages" pages of host memory pointed to by
* host_addr to the address "dev_addr" in device memory.
*
* The caller is responsible for checking the addresses ranges.
*
* Returns 0 if successful or a non-zero error number otherwise.
* If there is an error, no pages are mapped.
*/
int gasket_page_table_map(struct gasket_page_table *page_table, ulong host_addr,
ulong dev_addr, uint num_pages);
/*
* Un-map host pages from device memory.
* @page_table: Gasket page table pointer.
* @dev_addr: Starting device address of the pages to unmap.
* @num_pages: The number of [4kB] pages to unmap.
*
* Description: The inverse of gasket_map_pages. Unmaps pages from the device.
*/
void gasket_page_table_unmap(struct gasket_page_table *page_table,
ulong dev_addr, uint num_pages);
/*
* Unmap ALL host pages from device memory.
* @page_table: Gasket page table pointer.
*/
void gasket_page_table_unmap_all(struct gasket_page_table *page_table);
/*
* Unmap all host pages from device memory and reset the table to fully simple
* addressing.
* @page_table: Gasket page table pointer.
*/
void gasket_page_table_reset(struct gasket_page_table *page_table);
/*
* Reclaims unused page table memory.
* @page_table: Gasket page table pointer.
*
* Description: Examines the page table and frees any currently-unused
* allocations. Called internally on gasket_cleanup().
*/
void gasket_page_table_garbage_collect(struct gasket_page_table *page_table);
/*
* Retrieve the backing page for a device address.
* @page_table: Gasket page table pointer.
* @dev_addr: Gasket device address.
* @ppage: Pointer to a page pointer for the returned page.
* @poffset: Pointer to an unsigned long for the returned offset.
*
* Description: Interprets the address and looks up the corresponding page
* in the page table and the offset in that page. (We need an
* offset because the host page may be larger than the Gasket chip
* page it contains.)
*
* Returns 0 if successful, -1 for an error. The page pointer
* and offset are returned through the pointers, if successful.
*/
int gasket_page_table_lookup_page(struct gasket_page_table *page_table,
ulong dev_addr, struct page **page,
ulong *poffset);
/*
* Checks validity for input addrs and size.
* @page_table: Gasket page table pointer.
* @host_addr: Host address to check.
* @dev_addr: Gasket device address.
* @bytes: Size of the range to check (in bytes).
*
* Description: This call performs a number of checks to verify that the ranges
* specified by both addresses and the size are valid for mapping pages into
* device memory.
*
* Returns true if the mapping is bad, false otherwise.
*/
bool gasket_page_table_are_addrs_bad(struct gasket_page_table *page_table,
ulong host_addr, ulong dev_addr,
ulong bytes);
/*
* Checks validity for input dev addr and size.
* @page_table: Gasket page table pointer.
* @dev_addr: Gasket device address.
* @bytes: Size of the range to check (in bytes).
*
* Description: This call performs a number of checks to verify that the range
* specified by the device address and the size is valid for mapping pages into
* device memory.
*
* Returns true if the address is bad, false otherwise.
*/
bool gasket_page_table_is_dev_addr_bad(struct gasket_page_table *page_table,
ulong dev_addr, ulong bytes);
/*
* Gets maximum size for the given page table.
* @page_table: Gasket page table pointer.
*/
uint gasket_page_table_max_size(struct gasket_page_table *page_table);
/*
* Gets the total number of entries in the arg.
* @page_table: Gasket page table pointer.
*/
uint gasket_page_table_num_entries(struct gasket_page_table *page_table);
/*
* Gets the number of simple entries.
* @page_table: Gasket page table pointer.
*/
uint gasket_page_table_num_simple_entries(struct gasket_page_table *page_table);
/*
* Gets the number of actively pinned pages.
* @page_table: Gasket page table pointer.
*/
uint gasket_page_table_num_active_pages(struct gasket_page_table *page_table);
/*
* Get status of page table managed by @page_table.
* @page_table: Gasket page table pointer.
*/
int gasket_page_table_system_status(struct gasket_page_table *page_table);
/*
* Allocate a block of coherent memory.
* @gasket_dev: Gasket Device.
* @size: Size of the memory block.
* @dma_address: Dma address allocated by the kernel.
* @index: Index of the gasket_page_table within this Gasket device
*
* Description: Allocate a contiguous coherent memory block, DMA'ble
* by this device.
*/
int gasket_alloc_coherent_memory(struct gasket_dev *gasket_dev, uint64_t size,
dma_addr_t *dma_address, uint64_t index);
/* Release a block of contiguous coherent memory, in use by a device. */
int gasket_free_coherent_memory(struct gasket_dev *gasket_dev, uint64_t size,
dma_addr_t dma_address, uint64_t index);
/* Release all coherent memory. */
void gasket_free_coherent_memory_all(struct gasket_dev *gasket_dev,
uint64_t index);
/*
* Records the host_addr to coherent dma memory mapping.
* @gasket_dev: Gasket Device.
* @size: Size of the virtual address range to map.
* @dma_address: Dma address within the coherent memory range.
* @vma: Virtual address we wish to map to coherent memory.
*
* Description: For each page in the virtual address range, record the
* coherent page mapping.
*
* Does not perform validity checking.
*/
int gasket_set_user_virt(struct gasket_dev *gasket_dev, uint64_t size,
dma_addr_t dma_address, ulong vma);
#endif /* __GASKET_PAGE_TABLE_H__ */