arch/arm/mach-davinci/sram.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * mach-davinci/sram.c - DaVinci simple SRAM allocator
   4  *
   5  * Copyright (C) 2009 David Brownell
   6  */
   7 #include <linux/module.h>
   8 #include <linux/init.h>
   9 #include <linux/io.h>
  10 #include <linux/genalloc.h>
  11
  12 #include <mach/common.h>
  13 #include "sram.h"
  14
  15 static struct gen_pool *sram_pool;
  16
  17 struct gen_pool *sram_get_gen_pool(void)
  18 {
  19         return sram_pool;
  20 }
  21
  22 void *sram_alloc(size_t len, dma_addr_t *dma)
  23 {
  24         dma_addr_t dma_base = davinci_soc_info.sram_dma;
  25
  26         if (dma)
  27                 *dma = 0;
  28         if (!sram_pool || (dma && !dma_base))
  29                 return NULL;
  30
  31         return gen_pool_dma_alloc(sram_pool, len, dma);
  32
  33 }
  34 EXPORT_SYMBOL(sram_alloc);
  35
  36 void sram_free(void *addr, size_t len)
  37 {
  38         gen_pool_free(sram_pool, (unsigned long) addr, len);
  39 }
  40 EXPORT_SYMBOL(sram_free);
  41
  42
  43 /*
  44  * REVISIT This supports CPU and DMA access to/from SRAM, but it
  45  * doesn't (yet?) support some other notable uses of SRAM:  as TCM
  46  * for data and/or instructions; and holding code needed to enter
  47  * and exit suspend states (while DRAM can't be used).
  48  */
  49 static int __init sram_init(void)
  50 {
  51         phys_addr_t phys = davinci_soc_info.sram_dma;
  52         unsigned len = davinci_soc_info.sram_len;
  53         int status = 0;
  54         void __iomem *addr;
  55
  56         if (len) {
  57                 len = min_t(unsigned, len, SRAM_SIZE);
  58                 sram_pool = gen_pool_create(ilog2(SRAM_GRANULARITY), -1);
  59                 if (!sram_pool)
  60                         status = -ENOMEM;
  61         }
  62
  63         if (sram_pool) {
  64                 addr = ioremap(phys, len);
  65                 if (!addr)
  66                         return -ENOMEM;
  67                 status = gen_pool_add_virt(sram_pool, (unsigned long) addr,
  68                                            phys, len, -1);
  69                 if (status < 0)
  70                         iounmap(addr);
  71         }
  72
  73         WARN_ON(status < 0);
  74         return status;
  75 }
  76 core_initcall(sram_init);
  77