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misc: sram: implement reserved sram areas 

This implements support for defining reserved areas as subnodes,
to keep the genpool from using these.

Suggested-by: Rob Herring <robherring2@gmail.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Ulrich Prinz <ulrich.prinz@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Heiko Stübner 2014-02-25 12:46:34 +01:00 committed by Greg Kroah-Hartman
parent 96328cdae3
commit 2da19688f4
1 changed files with 118 additions and 7 deletions
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125
drivers/misc/sram.c
View File

@ -24,6 +24,9 @@
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/list.h>
#include <linux/list_sort.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
@ -36,14 +39,35 @@ struct sram_dev {
struct clk *clk;
};
struct sram_reserve {
struct list_head list;
u32 start;
u32 size;
};
static int sram_reserve_cmp(void *priv, struct list_head *a,
struct list_head *b)
{
struct sram_reserve *ra = list_entry(a, struct sram_reserve, list);
struct sram_reserve *rb = list_entry(b, struct sram_reserve, list);
return ra->start - rb->start;
}
static int sram_probe(struct platform_device *pdev)
{
void __iomem *virt_base;
struct sram_dev *sram;
struct resource *res;
unsigned long size;
struct device_node *np = pdev->dev.of_node, *child;
unsigned long size, cur_start, cur_size;
struct sram_reserve *rblocks, *block;
struct list_head reserve_list;
unsigned int nblocks;
int ret;
INIT_LIST_HEAD(&reserve_list);
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
virt_base = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(virt_base))
@ -65,19 +89,106 @@ static int sram_probe(struct platform_device *pdev)
if (!sram->pool)
return -ENOMEM;
ret = gen_pool_add_virt(sram->pool, (unsigned long)virt_base,
res->start, size, -1);
if (ret < 0) {
if (sram->clk)
clk_disable_unprepare(sram->clk);
return ret;
/*
* We need an additional block to mark the end of the memory region
* after the reserved blocks from the dt are processed.
*/
nblocks = (np) ? of_get_available_child_count(np) + 1 : 1;
rblocks = kmalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
if (!rblocks) {
ret = -ENOMEM;
goto err_alloc;
}
block = &rblocks[0];
for_each_available_child_of_node(np, child) {
struct resource child_res;
ret = of_address_to_resource(child, 0, &child_res);
if (ret < 0) {
dev_err(&pdev->dev,
"could not get address for node %s\n",
child->full_name);
goto err_chunks;
}
if (child_res.start < res->start || child_res.end > res->end) {
dev_err(&pdev->dev,
"reserved block %s outside the sram area\n",
child->full_name);
ret = -EINVAL;
goto err_chunks;
}
block->start = child_res.start - res->start;
block->size = resource_size(&child_res);
list_add_tail(&block->list, &reserve_list);
dev_dbg(&pdev->dev, "found reserved block 0x%x-0x%x\n",
block->start,
block->start + block->size);
block++;
}
/* the last chunk marks the end of the region */
rblocks[nblocks - 1].start = size;
rblocks[nblocks - 1].size = 0;
list_add_tail(&rblocks[nblocks - 1].list, &reserve_list);
list_sort(NULL, &reserve_list, sram_reserve_cmp);
cur_start = 0;
list_for_each_entry(block, &reserve_list, list) {
/* can only happen if sections overlap */
if (block->start < cur_start) {
dev_err(&pdev->dev,
"block at 0x%x starts after current offset 0x%lx\n",
block->start, cur_start);
ret = -EINVAL;
goto err_chunks;
}
/* current start is in a reserved block, so continue after it */
if (block->start == cur_start) {
cur_start = block->start + block->size;
continue;
}
/*
* allocate the space between the current starting
* address and the following reserved block, or the
* end of the region.
*/
cur_size = block->start - cur_start;
dev_dbg(&pdev->dev, "adding chunk 0x%lx-0x%lx\n",
cur_start, cur_start + cur_size);
ret = gen_pool_add_virt(sram->pool,
(unsigned long)virt_base + cur_start,
res->start + cur_start, cur_size, -1);
if (ret < 0)
goto err_chunks;
/* next allocation after this reserved block */
cur_start = block->start + block->size;
}
kfree(rblocks);
platform_set_drvdata(pdev, sram);
dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base);
return 0;
err_chunks:
kfree(rblocks);
err_alloc:
if (sram->clk)
clk_disable_unprepare(sram->clk);
return ret;
}
static int sram_remove(struct platform_device *pdev)