1*ee844305SPeter Ujfalusi // SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause) 2*ee844305SPeter Ujfalusi // 3*ee844305SPeter Ujfalusi // This file is provided under a dual BSD/GPLv2 license. When using or 4*ee844305SPeter Ujfalusi // redistributing this file, you may do so under either license. 5*ee844305SPeter Ujfalusi // 6*ee844305SPeter Ujfalusi // Copyright(c) 2018-2022 Intel Corporation. All rights reserved. 7*ee844305SPeter Ujfalusi // 8*ee844305SPeter Ujfalusi // Author: Keyon Jie <yang.jie@linux.intel.com> 9*ee844305SPeter Ujfalusi // 10*ee844305SPeter Ujfalusi 11*ee844305SPeter Ujfalusi #include <asm/unaligned.h> 12*ee844305SPeter Ujfalusi #include <linux/io-64-nonatomic-lo-hi.h> 13*ee844305SPeter Ujfalusi #include <linux/device.h> 14*ee844305SPeter Ujfalusi #include <sound/memalloc.h> 15*ee844305SPeter Ujfalusi #include <linux/module.h> 16*ee844305SPeter Ujfalusi #include "sof-utils.h" 17*ee844305SPeter Ujfalusi 18*ee844305SPeter Ujfalusi /* 19*ee844305SPeter Ujfalusi * Generic buffer page table creation. 20*ee844305SPeter Ujfalusi * Take the each physical page address and drop the least significant unused 21*ee844305SPeter Ujfalusi * bits from each (based on PAGE_SIZE). Then pack valid page address bits 22*ee844305SPeter Ujfalusi * into compressed page table. 23*ee844305SPeter Ujfalusi */ 24*ee844305SPeter Ujfalusi 25*ee844305SPeter Ujfalusi int snd_sof_create_page_table(struct device *dev, 26*ee844305SPeter Ujfalusi struct snd_dma_buffer *dmab, 27*ee844305SPeter Ujfalusi unsigned char *page_table, size_t size) 28*ee844305SPeter Ujfalusi { 29*ee844305SPeter Ujfalusi int i, pages; 30*ee844305SPeter Ujfalusi 31*ee844305SPeter Ujfalusi pages = snd_sgbuf_aligned_pages(size); 32*ee844305SPeter Ujfalusi 33*ee844305SPeter Ujfalusi dev_dbg(dev, "generating page table for %p size 0x%zx pages %d\n", 34*ee844305SPeter Ujfalusi dmab->area, size, pages); 35*ee844305SPeter Ujfalusi 36*ee844305SPeter Ujfalusi for (i = 0; i < pages; i++) { 37*ee844305SPeter Ujfalusi /* 38*ee844305SPeter Ujfalusi * The number of valid address bits for each page is 20. 39*ee844305SPeter Ujfalusi * idx determines the byte position within page_table 40*ee844305SPeter Ujfalusi * where the current page's address is stored 41*ee844305SPeter Ujfalusi * in the compressed page_table. 42*ee844305SPeter Ujfalusi * This can be calculated by multiplying the page number by 2.5. 43*ee844305SPeter Ujfalusi */ 44*ee844305SPeter Ujfalusi u32 idx = (5 * i) >> 1; 45*ee844305SPeter Ujfalusi u32 pfn = snd_sgbuf_get_addr(dmab, i * PAGE_SIZE) >> PAGE_SHIFT; 46*ee844305SPeter Ujfalusi u8 *pg_table; 47*ee844305SPeter Ujfalusi 48*ee844305SPeter Ujfalusi dev_vdbg(dev, "pfn i %i idx %d pfn %x\n", i, idx, pfn); 49*ee844305SPeter Ujfalusi 50*ee844305SPeter Ujfalusi pg_table = (u8 *)(page_table + idx); 51*ee844305SPeter Ujfalusi 52*ee844305SPeter Ujfalusi /* 53*ee844305SPeter Ujfalusi * pagetable compression: 54*ee844305SPeter Ujfalusi * byte 0 byte 1 byte 2 byte 3 byte 4 byte 5 55*ee844305SPeter Ujfalusi * ___________pfn 0__________ __________pfn 1___________ _pfn 2... 56*ee844305SPeter Ujfalusi * .... .... .... .... .... .... .... .... .... .... .... 57*ee844305SPeter Ujfalusi * It is created by: 58*ee844305SPeter Ujfalusi * 1. set current location to 0, PFN index i to 0 59*ee844305SPeter Ujfalusi * 2. put pfn[i] at current location in Little Endian byte order 60*ee844305SPeter Ujfalusi * 3. calculate an intermediate value as 61*ee844305SPeter Ujfalusi * x = (pfn[i+1] << 4) | (pfn[i] & 0xf) 62*ee844305SPeter Ujfalusi * 4. put x at offset (current location + 2) in LE byte order 63*ee844305SPeter Ujfalusi * 5. increment current location by 5 bytes, increment i by 2 64*ee844305SPeter Ujfalusi * 6. continue to (2) 65*ee844305SPeter Ujfalusi */ 66*ee844305SPeter Ujfalusi if (i & 1) 67*ee844305SPeter Ujfalusi put_unaligned_le32((pg_table[0] & 0xf) | pfn << 4, 68*ee844305SPeter Ujfalusi pg_table); 69*ee844305SPeter Ujfalusi else 70*ee844305SPeter Ujfalusi put_unaligned_le32(pfn, pg_table); 71*ee844305SPeter Ujfalusi } 72*ee844305SPeter Ujfalusi 73*ee844305SPeter Ujfalusi return pages; 74*ee844305SPeter Ujfalusi } 75*ee844305SPeter Ujfalusi EXPORT_SYMBOL(snd_sof_create_page_table); 76*ee844305SPeter Ujfalusi 77*ee844305SPeter Ujfalusi MODULE_LICENSE("Dual BSD/GPL"); 78