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sram.c

/*
 * Simple memory allocator for on-board SRAM
 *
 *
 * Maintainer : Sylvain Munaut <tnt@246tNt.com>
 *
 * Copyright (C) 2005 Sylvain Munaut <tnt@246tNt.com>
 *
 * This file is licensed under the terms of the GNU General Public License
 * version 2. This program is licensed "as is" without any warranty of any
 * kind, whether express or implied.
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/ioport.h>
#include <linux/of.h>

#include <asm/io.h>
#include <asm/mmu.h>

#include "sram.h"


/* Struct keeping our 'state' */
struct bcom_sram *bcom_sram = NULL;
EXPORT_SYMBOL_GPL(bcom_sram); /* needed for inline functions */


/* ======================================================================== */
/* Public API                                                               */
/* ======================================================================== */
/* DO NOT USE in interrupts, if needed in irq handler, we should use the
   _irqsave version of the spin_locks */

int bcom_sram_init(struct device_node *sram_node, char *owner)
{
      int rv;
      const u32 *regaddr_p;
      u64 regaddr64, size64;
      unsigned int psize;

      /* Create our state struct */
      if (bcom_sram) {
            printk(KERN_ERR "%s: bcom_sram_init: "
                  "Already initialized !\n", owner);
            return -EBUSY;
      }

      bcom_sram = kmalloc(sizeof(struct bcom_sram), GFP_KERNEL);
      if (!bcom_sram) {
            printk(KERN_ERR "%s: bcom_sram_init: "
                  "Couldn't allocate internal state !\n", owner);
            return -ENOMEM;
      }

      /* Get address and size of the sram */
      regaddr_p = of_get_address(sram_node, 0, &size64, NULL);
      if (!regaddr_p) {
            printk(KERN_ERR "%s: bcom_sram_init: "
                  "Invalid device node !\n", owner);
            rv = -EINVAL;
            goto error_free;
      }

      regaddr64 = of_translate_address(sram_node, regaddr_p);

      bcom_sram->base_phys = (phys_addr_t) regaddr64;
      bcom_sram->size = (unsigned int) size64;

      /* Request region */
      if (!request_mem_region(bcom_sram->base_phys, bcom_sram->size, owner)) {
            printk(KERN_ERR "%s: bcom_sram_init: "
                  "Couldn't request region !\n", owner);
            rv = -EBUSY;
            goto error_free;
      }

      /* Map SRAM */
            /* sram is not really __iomem */
      bcom_sram->base_virt = (void*) ioremap(bcom_sram->base_phys, bcom_sram->size);

      if (!bcom_sram->base_virt) {
            printk(KERN_ERR "%s: bcom_sram_init: "
                  "Map error SRAM zone 0x%08lx (0x%0x)!\n",
                  owner, (long)bcom_sram->base_phys, bcom_sram->size );
            rv = -ENOMEM;
            goto error_release;
      }

      /* Create an rheap (defaults to 32 bits word alignment) */
      bcom_sram->rh = rh_create(4);

      /* Attach the free zones */
#if 0
      /* Currently disabled ... for future use only */
      reg_addr_p = of_get_property(sram_node, "available", &psize);
#else
      regaddr_p = NULL;
      psize = 0;
#endif

      if (!regaddr_p || !psize) {
            /* Attach the whole zone */
            rh_attach_region(bcom_sram->rh, 0, bcom_sram->size);
      } else {
            /* Attach each zone independently */
            while (psize >= 2 * sizeof(u32)) {
                  phys_addr_t zbase = of_translate_address(sram_node, regaddr_p);
                  rh_attach_region(bcom_sram->rh, zbase - bcom_sram->base_phys, regaddr_p[1]);
                  regaddr_p += 2;
                  psize -= 2 * sizeof(u32);
            }
      }

      /* Init our spinlock */
      spin_lock_init(&bcom_sram->lock);

      return 0;

error_release:
      release_mem_region(bcom_sram->base_phys, bcom_sram->size);
error_free:
      kfree(bcom_sram);
      bcom_sram = NULL;

      return rv;
}
EXPORT_SYMBOL_GPL(bcom_sram_init);

void bcom_sram_cleanup(void)
{
      /* Free resources */
      if (bcom_sram) {
            rh_destroy(bcom_sram->rh);
            iounmap((void __iomem *)bcom_sram->base_virt);
            release_mem_region(bcom_sram->base_phys, bcom_sram->size);
            kfree(bcom_sram);
            bcom_sram = NULL;
      }
}
EXPORT_SYMBOL_GPL(bcom_sram_cleanup);

void* bcom_sram_alloc(int size, int align, phys_addr_t *phys)
{
      unsigned long offset;

      spin_lock(&bcom_sram->lock);
      offset = rh_alloc_align(bcom_sram->rh, size, align, NULL);
      spin_unlock(&bcom_sram->lock);

      if (IS_ERR_VALUE(offset))
            return NULL;

      *phys = bcom_sram->base_phys + offset;
      return bcom_sram->base_virt + offset;
}
EXPORT_SYMBOL_GPL(bcom_sram_alloc);

void bcom_sram_free(void *ptr)
{
      unsigned long offset;

      if (!ptr)
            return;

      offset = ptr - bcom_sram->base_virt;

      spin_lock(&bcom_sram->lock);
      rh_free(bcom_sram->rh, offset);
      spin_unlock(&bcom_sram->lock);
}
EXPORT_SYMBOL_GPL(bcom_sram_free);


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