arm/mach-davinci/sram.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * mach-davinci/sram.c - DaVinci simple SRAM allocator
0004  *
0005  * Copyright (C) 2009 David Brownell
0006  */
0007 #include <linux/module.h>
0008 #include <linux/init.h>
0009 #include <linux/io.h>
0010 #include <linux/genalloc.h>
0011
0012 #include "common.h"
0013 #include "sram.h"
0014
0015 static struct gen_pool *sram_pool;
0016
0017 struct gen_pool *sram_get_gen_pool(void)
0018 {
0019     return sram_pool;
0020 }
0021
0022 void *sram_alloc(size_t len, dma_addr_t *dma)
0023 {
0024     dma_addr_t dma_base = davinci_soc_info.sram_dma;
0025
0026     if (dma)
0027         *dma = 0;
0028     if (!sram_pool || (dma && !dma_base))
0029         return NULL;
0030
0031     return gen_pool_dma_alloc(sram_pool, len, dma);
0032
0033 }
0034 EXPORT_SYMBOL(sram_alloc);
0035
0036 void sram_free(void *addr, size_t len)
0037 {
0038     gen_pool_free(sram_pool, (unsigned long) addr, len);
0039 }
0040 EXPORT_SYMBOL(sram_free);
0041
0042
0043 /*
0044  * REVISIT This supports CPU and DMA access to/from SRAM, but it
0045  * doesn't (yet?) support some other notable uses of SRAM:  as TCM
0046  * for data and/or instructions; and holding code needed to enter
0047  * and exit suspend states (while DRAM can't be used).
0048  */
0049 static int __init sram_init(void)
0050 {
0051     phys_addr_t phys = davinci_soc_info.sram_dma;
0052     unsigned len = davinci_soc_info.sram_len;
0053     int status = 0;
0054     void __iomem *addr;
0055
0056     if (len) {
0057         len = min_t(unsigned, len, SRAM_SIZE);
0058         sram_pool = gen_pool_create(ilog2(SRAM_GRANULARITY), -1);
0059         if (!sram_pool)
0060             status = -ENOMEM;
0061     }
0062
0063     if (sram_pool) {
0064         addr = ioremap(phys, len);
0065         if (!addr)
0066             return -ENOMEM;
0067         status = gen_pool_add_virt(sram_pool, (unsigned long) addr,
0068                        phys, len, -1);
0069         if (status < 0)
0070             iounmap(addr);
0071     }
0072
0073     WARN_ON(status < 0);
0074     return status;
0075 }
0076 core_initcall(sram_init);
0077