include/linux/vcm_mm.h

/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 */

/* Architecture-specific VCM functions */

/* Device attributes */

/*
 * Sharing attributes. Pick only one.
 */
#define VCM_DEV_ATTR_NON_SH 	(0x00)
#define VCM_DEV_ATTR_SH		(0x04)

/*
 * Caching attributes. Pick only one.
 */
#define VCM_DEV_ATTR_NONCACHED		(0x00)
#define VCM_DEV_ATTR_CACHED_WB_WA	(0x01)
#define VCM_DEV_ATTR_CACHED_WB_NWA	(0x02)
#define VCM_DEV_ATTR_CACHED_WT		(0x03)

/*
 * A "good" default set of attributes: shareable and non-cacheable.
 */
#define VCM_DEV_DEFAULT_ATTR	(VCM_DEV_ATTR_SH | VCM_DEV_ATTR_NONCACHED)

/**
 * set_arm7_pte_attr() - Set ARMv7 page table attributes
 * pt_base	Virtual address of the first-level page table
 * @va		Virtual address whose attributes are to be set
 * @len		Page size used to map the given virtual address
 * @attr	Attributes to set for this mapping.
 *
 * Modify a mapping attribute. The base address of the page table must
 * be a virtual address containing a valid ARMv7 page table.  The
 * virtual address must refer to an existing mapping and must be
 * aligned to the length with which it was mapped. The mapping length
 * must similarly be the same as was specified when the mapping was
 * made (one of 4KB, 64KB, 1MB, or 16MB). The attribute must be one of
 * the shareability attributes above ORed with one of the cacheability
 * attributes. Any previous attributes are completely replaced by the
 * most recent call to this function. This function only sets the
 * cacheability and shareability attributes. This is accomplished by
 * modifying the TEX class and the S bit in the PTE. It is an error to
 * call this function without having called vcm_setup_tex_classes at
 * least once.
 *
 * The return value is zero on success and non-zero on failure.
 */
int set_arm7_pte_attr(unsigned long pt_base, unsigned long va,
		     unsigned long len,	unsigned int attr);


/**
 * cpu_set_attr() - Set page table attributes on the CPU's page tables
 * @va		Virtual address whose attributes are to be set
 * @len		Page size used to map the given virtual address
 * @attr	Attributes to set for this mapping.
 *
 * Modify a mapping attribute within the ARM page tables. The va must
 * refer to an existing mapping and must be aligned to the length with
 * which it was mapped. The mapping length must similarly be the same
 * as was specified when the mapping was made (one of 4KB, 64KB, 1MB,
 * or 16MB). The attribute must be one of the shareability attributes
 * above ORed with one of the cacheability attributes. Any previous
 * attributes are completely replaced by the most recent call to this
 * function. This function only sets the cacheability and shareability
 * attributes. This is accomplished by modifying the TEX class and the
 * S bit in the PTE. It is an error to call this function without
 * having called vcm_setup_tex_classes at least once. It is an error
 * to call this function on any system using a memory configuration
 * that is anything OTHER than ARMv7 with TEX remap enabled. Only the
 * HW page tables are modified; the Linux page tables are left
 * untouched.
 *
 * The return value is zero on success and non-zero on failure.
 */
int cpu_set_attr(unsigned long va, unsigned long len, unsigned int attr);


/**
 * vcm_setup_tex_classes() - Prepare TEX class table for use
 *
 * Initialize the attribute mapping table by examining the TEX classes
 * used by the CPU and finding the classes that match the device
 * attributes (VCM_DEV_xx) defined above. This function is only
 * relevant if TEX remap is enabled. The results will be unpredictable
 * and irrelevant if TEX remap is not in use. It is an error to call
 * this function in any system using a memory configuration of
 * anything OTHER than ARMv7 with TEX remap enabled.
 *
 * The return value is zero on success or non-zero on failure. In the
 * present version, a failure will result in a panic.
 */
int vcm_setup_tex_classes(void);