1/* 2 * mach-davinci/sram.c - DaVinci simple SRAM allocator 3 * 4 * Copyright (C) 2009 David Brownell 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License as published by 8 * the Free Software Foundation; either version 2 of the License, or 9 * (at your option) any later version. 10 */ 11#include <linux/module.h> 12#include <linux/init.h> 13#include <linux/genalloc.h> 14 15#include <mach/common.h> 16#include <mach/sram.h> 17 18static struct gen_pool *sram_pool; 19 20void *sram_alloc(size_t len, dma_addr_t *dma) 21{ 22 unsigned long vaddr; 23 dma_addr_t dma_base = davinci_soc_info.sram_dma; 24 25 if (dma) 26 *dma = 0; 27 if (!sram_pool || (dma && !dma_base)) 28 return NULL; 29 30 vaddr = gen_pool_alloc(sram_pool, len); 31 if (!vaddr) 32 return NULL; 33 34 if (dma) 35 *dma = dma_base + (vaddr - SRAM_VIRT); 36 return (void *)vaddr; 37 38} 39EXPORT_SYMBOL(sram_alloc); 40 41void sram_free(void *addr, size_t len) 42{ 43 gen_pool_free(sram_pool, (unsigned long) addr, len); 44} 45EXPORT_SYMBOL(sram_free); 46 47 48/* 49 * REVISIT This supports CPU and DMA access to/from SRAM, but it 50 * doesn't (yet?) support some other notable uses of SRAM: as TCM 51 * for data and/or instructions; and holding code needed to enter 52 * and exit suspend states (while DRAM can't be used). 53 */ 54static int __init sram_init(void) 55{ 56 unsigned len = davinci_soc_info.sram_len; 57 int status = 0; 58 59 if (len) { 60 len = min_t(unsigned, len, SRAM_SIZE); 61 sram_pool = gen_pool_create(ilog2(SRAM_GRANULARITY), -1); 62 if (!sram_pool) 63 status = -ENOMEM; 64 } 65 if (sram_pool) 66 status = gen_pool_add(sram_pool, SRAM_VIRT, len, -1); 67 WARN_ON(status < 0); 68 return status; 69} 70core_initcall(sram_init); 71