linux/drivers/misc/sram.c
Abhilash Kesavan 0ab163ad1e misc: sram: switch to ioremap_wc from ioremap
Currently, the SRAM allocator returns device memory via ioremap.
This causes issues on ARM64 when the internal SoC SRAM allocated by
the generic sram driver is used for audio playback. The destination
buffer address (which is ioremapped SRAM) is not 64-bit aligned for
certain streams (e.g. 44.1k sampling rate). In such cases we get
unhandled alignment faults. Use ioremap_wc in place of ioremap which
gives us normal non-cacheable memory instead of device memory.

Signed-off-by: Abhilash Kesavan <a.kesavan@samsung.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-03-16 21:11:32 +01:00

240 lines
5.8 KiB
C

/*
* Generic on-chip SRAM allocation driver
*
* Copyright (C) 2012 Philipp Zabel, Pengutronix
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
* MA 02110-1301, USA.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/clk.h>
#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>
#include <linux/genalloc.h>
#define SRAM_GRANULARITY 32
struct sram_dev {
struct gen_pool *pool;
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;
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);
if (!res) {
dev_err(&pdev->dev, "found no memory resource\n");
return -EINVAL;
}
size = resource_size(res);
if (!devm_request_mem_region(&pdev->dev,
res->start, size, pdev->name)) {
dev_err(&pdev->dev, "could not request region for resource\n");
return -EBUSY;
}
virt_base = devm_ioremap_wc(&pdev->dev, res->start, size);
if (IS_ERR(virt_base))
return PTR_ERR(virt_base);
sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);
if (!sram)
return -ENOMEM;
sram->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(sram->clk))
sram->clk = NULL;
else
clk_prepare_enable(sram->clk);
sram->pool = devm_gen_pool_create(&pdev->dev, ilog2(SRAM_GRANULARITY), -1);
if (!sram->pool)
return -ENOMEM;
/*
* 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)
{
struct sram_dev *sram = platform_get_drvdata(pdev);
if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool))
dev_dbg(&pdev->dev, "removed while SRAM allocated\n");
if (sram->clk)
clk_disable_unprepare(sram->clk);
return 0;
}
#ifdef CONFIG_OF
static const struct of_device_id sram_dt_ids[] = {
{ .compatible = "mmio-sram" },
{}
};
#endif
static struct platform_driver sram_driver = {
.driver = {
.name = "sram",
.of_match_table = of_match_ptr(sram_dt_ids),
},
.probe = sram_probe,
.remove = sram_remove,
};
static int __init sram_init(void)
{
return platform_driver_register(&sram_driver);
}
postcore_initcall(sram_init);