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/*
* Coherency fabric (Aurora) support for Armada 370 and XP platforms.
*
* Copyright (C) 2012 Marvell
*
* Yehuda Yitschak <yehuday@marvell.com>
* Gregory Clement <gregory.clement@free-electrons.com>
* Thomas Petazzoni <thomas.petazzoni@free-electrons.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.
*
* The Armada 370 and Armada XP SOCs have a coherency fabric which is
* responsible for ensuring hardware coherency between all CPUs and between
* CPUs and I/O masters. This file initializes the coherency fabric and
* supplies basic routines for configuring and controlling hardware coherency
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/of_address.h>
#include <linux/io.h>
#include <linux/smp.h>
#include <linux/dma-mapping.h>
#include <linux/platform_device.h>
#include <asm/smp_plat.h>
#include <asm/cacheflush.h>
#include "armada-370-xp.h"
#include "coherency.h"
unsigned long coherency_phys_base;
static void __iomem *coherency_base;
static void __iomem *coherency_cpu_base;
/* Coherency fabric registers */
#define COHERENCY_FABRIC_CFG_OFFSET 0x4
#define IO_SYNC_BARRIER_CTL_OFFSET 0x0
static struct of_device_id of_coherency_table[] = {
{.compatible = "marvell,coherency-fabric"},
{ /* end of list */ },
};
/* Function defined in coherency_ll.S */
int ll_set_cpu_coherent(void __iomem *base_addr, unsigned int hw_cpu_id);
int set_cpu_coherent(unsigned int hw_cpu_id, int smp_group_id)
{
if (!coherency_base) {
pr_warn("Can't make CPU %d cache coherent.\n", hw_cpu_id);
pr_warn("Coherency fabric is not initialized\n");
return 1;
}
return ll_set_cpu_coherent(coherency_base, hw_cpu_id);
}
static inline void mvebu_hwcc_sync_io_barrier(void)
{
writel(0x1, coherency_cpu_base + IO_SYNC_BARRIER_CTL_OFFSET);
while (readl(coherency_cpu_base + IO_SYNC_BARRIER_CTL_OFFSET) & 0x1);
}
static dma_addr_t mvebu_hwcc_dma_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
struct dma_attrs *attrs)
{
if (dir != DMA_TO_DEVICE)
mvebu_hwcc_sync_io_barrier();
return pfn_to_dma(dev, page_to_pfn(page)) + offset;
}
static void mvebu_hwcc_dma_unmap_page(struct device *dev, dma_addr_t dma_handle,
size_t size, enum dma_data_direction dir,
struct dma_attrs *attrs)
{
if (dir != DMA_TO_DEVICE)
mvebu_hwcc_sync_io_barrier();
}
static void mvebu_hwcc_dma_sync(struct device *dev, dma_addr_t dma_handle,
size_t size, enum dma_data_direction dir)
{
if (dir != DMA_TO_DEVICE)
mvebu_hwcc_sync_io_barrier();
}
static struct dma_map_ops mvebu_hwcc_dma_ops = {
.alloc = arm_dma_alloc,
.free = arm_dma_free,
.mmap = arm_dma_mmap,
.map_page = mvebu_hwcc_dma_map_page,
.unmap_page = mvebu_hwcc_dma_unmap_page,
.get_sgtable = arm_dma_get_sgtable,
.map_sg = arm_dma_map_sg,
.unmap_sg = arm_dma_unmap_sg,
.sync_single_for_cpu = mvebu_hwcc_dma_sync,
.sync_single_for_device = mvebu_hwcc_dma_sync,
.sync_sg_for_cpu = arm_dma_sync_sg_for_cpu,
.sync_sg_for_device = arm_dma_sync_sg_for_device,
.set_dma_mask = arm_dma_set_mask,
};
static int mvebu_hwcc_platform_notifier(struct notifier_block *nb,
unsigned long event, void *__dev)
{
struct device *dev = __dev;
if (event != BUS_NOTIFY_ADD_DEVICE)
return NOTIFY_DONE;
set_dma_ops(dev, &mvebu_hwcc_dma_ops);
return NOTIFY_OK;
}
static struct notifier_block mvebu_hwcc_platform_nb = {
.notifier_call = mvebu_hwcc_platform_notifier,
};
int __init coherency_init(void)
{
struct device_node *np;
/*
* The coherency fabric is needed:
* - For coherency between processors on Armada XP, so only
* when SMP is enabled.
* - For coherency between the processor and I/O devices, but
* this coherency requires many pre-requisites (write
* allocate cache policy, shareable pages, SMP bit set) that
* are only meant in SMP situations.
*
* Note that this means that on Armada 370, there is currently
* no way to use hardware I/O coherency, because even when
* CONFIG_SMP is enabled, is_smp() returns false due to the
* Armada 370 being a single-core processor. To lift this
* limitation, we would have to find a way to make the cache
* policy set to write-allocate (on all Armada SoCs), and to
* set the shareable attribute in page tables (on all Armada
* SoCs except the Armada 370). Unfortunately, such decisions
* are taken very early in the kernel boot process, at a point
* where we don't know yet on which SoC we are running.
*/
if (!is_smp())
return 0;
np = of_find_matching_node(NULL, of_coherency_table);
if (np) {
struct resource res;
pr_info("Initializing Coherency fabric\n");
of_address_to_resource(np, 0, &res);
coherency_phys_base = res.start;
/*
* Ensure secondary CPUs will see the updated value,
* which they read before they join the coherency
* fabric, and therefore before they are coherent with
* the boot CPU cache.
*/
sync_cache_w(&coherency_phys_base);
coherency_base = of_iomap(np, 0);
coherency_cpu_base = of_iomap(np, 1);
set_cpu_coherent(cpu_logical_map(smp_processor_id()), 0);
of_node_put(np);
}
return 0;
}
static int __init coherency_late_init(void)
{
struct device_node *np;
if (!is_smp())
return 0;
np = of_find_matching_node(NULL, of_coherency_table);
if (np) {
bus_register_notifier(&platform_bus_type,
&mvebu_hwcc_platform_nb);
of_node_put(np);
}
return 0;
}
postcore_initcall(coherency_late_init);
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