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/io.h> 14 #include <linux/genalloc.h> 15 16 #include <mach/common.h> 17 #include <mach/sram.h> 18 19 static struct gen_pool *sram_pool; 20 21 struct gen_pool *sram_get_gen_pool(void) 22 { 23 return sram_pool; 24 } 25 26 void *sram_alloc(size_t len, dma_addr_t *dma) 27 { 28 unsigned long vaddr; 29 dma_addr_t dma_base = davinci_soc_info.sram_dma; 30 31 if (dma) 32 *dma = 0; 33 if (!sram_pool || (dma && !dma_base)) 34 return NULL; 35 36 vaddr = gen_pool_alloc(sram_pool, len); 37 if (!vaddr) 38 return NULL; 39 40 if (dma) 41 *dma = gen_pool_virt_to_phys(sram_pool, vaddr); 42 return (void *)vaddr; 43 44 } 45 EXPORT_SYMBOL(sram_alloc); 46 47 void sram_free(void *addr, size_t len) 48 { 49 gen_pool_free(sram_pool, (unsigned long) addr, len); 50 } 51 EXPORT_SYMBOL(sram_free); 52 53 54 /* 55 * REVISIT This supports CPU and DMA access to/from SRAM, but it 56 * doesn't (yet?) support some other notable uses of SRAM: as TCM 57 * for data and/or instructions; and holding code needed to enter 58 * and exit suspend states (while DRAM can't be used). 59 */ 60 static int __init sram_init(void) 61 { 62 phys_addr_t phys = davinci_soc_info.sram_dma; 63 unsigned len = davinci_soc_info.sram_len; 64 int status = 0; 65 void *addr; 66 67 if (len) { 68 len = min_t(unsigned, len, SRAM_SIZE); 69 sram_pool = gen_pool_create(ilog2(SRAM_GRANULARITY), -1); 70 if (!sram_pool) 71 status = -ENOMEM; 72 } 73 74 if (sram_pool) { 75 addr = ioremap(phys, len); 76 if (!addr) 77 return -ENOMEM; 78 status = gen_pool_add_virt(sram_pool, (unsigned)addr, 79 phys, len, -1); 80 if (status < 0) 81 iounmap(addr); 82 } 83 84 WARN_ON(status < 0); 85 return status; 86 } 87 core_initcall(sram_init); 88 89