[PATCH 2/2] arm: mvebu: Add hardware I/O Coherency support
Gregory CLEMENT
gregory.clement at free-electrons.com
Wed Oct 24 04:04:01 EDT 2012
Armada 370 and XP come with an unit called coherency fabric. This unit
allows to use the Armada XP as a nearly coherent architecture. The
coherency mechanism uses snoop filters to ensure the coherency between
caches, DRAM and devices. This mechanism needs a synchronization
barrier which guarantees that all memory write initiated by the
devices has reached their target and do not reside in intermediate
write buffers. That's why the architecture is not totally coherent and
we need to provide our own functions for some DMA operations.
Beside the use of the coherency fabric, the device units will have to
set the attribute flag to select the accurate coherency process for
the memory transaction. This is done each device driver programs the
DRAM address windows. The value of the attribute set by the driver is
retrieved through the orion_addr_map_cfg struct filled during the
early initialization of the platform.
Signed-off-by: Gregory CLEMENT <gregory.clement at free-electrons.com>
Reviewed-by: Yehuda Yitschak <yehuday at marvell.com>
---
arch/arm/boot/dts/armada-370-xp.dtsi | 3 +-
arch/arm/mach-mvebu/addr-map.c | 3 ++
arch/arm/mach-mvebu/armada-370-xp.c | 1 +
arch/arm/mach-mvebu/coherency.c | 87 ++++++++++++++++++++++++++++++++++
arch/arm/mach-mvebu/common.h | 2 +
5 files changed, 95 insertions(+), 1 deletion(-)
diff --git a/arch/arm/boot/dts/armada-370-xp.dtsi b/arch/arm/boot/dts/armada-370-xp.dtsi
index 18ba60b..af22e53 100644
--- a/arch/arm/boot/dts/armada-370-xp.dtsi
+++ b/arch/arm/boot/dts/armada-370-xp.dtsi
@@ -38,7 +38,8 @@
coherency-fabric at d0020200 {
compatible = "marvell,coherency-fabric";
- reg = <0xd0020200 0xb0>;
+ reg = <0xd0020200 0xb0>,
+ <0xd0021010 0x1c>;
};
soc {
diff --git a/arch/arm/mach-mvebu/addr-map.c b/arch/arm/mach-mvebu/addr-map.c
index fe454a4..595f6b7 100644
--- a/arch/arm/mach-mvebu/addr-map.c
+++ b/arch/arm/mach-mvebu/addr-map.c
@@ -108,6 +108,9 @@ static int __init armada_setup_cpu_mbus(void)
addr_map_cfg.bridge_virt_base = mbus_unit_addr_decoding_base;
+ if (of_find_compatible_node(NULL, NULL, "marvell,coherency-fabric"))
+ addr_map_cfg.hw_io_coherency = 1;
+
/*
* Disable, clear and configure windows.
*/
diff --git a/arch/arm/mach-mvebu/armada-370-xp.c b/arch/arm/mach-mvebu/armada-370-xp.c
index 41431a1..3517f7d 100644
--- a/arch/arm/mach-mvebu/armada-370-xp.c
+++ b/arch/arm/mach-mvebu/armada-370-xp.c
@@ -49,6 +49,7 @@ struct sys_timer armada_370_xp_timer = {
static void __init armada_370_xp_dt_init(void)
{
+ armada_370_xp_coherency_iocache_init();
of_platform_populate(NULL, of_default_bus_match_table, NULL, NULL);
}
diff --git a/arch/arm/mach-mvebu/coherency.c b/arch/arm/mach-mvebu/coherency.c
index 71e27ba..a596ca9 100644
--- a/arch/arm/mach-mvebu/coherency.c
+++ b/arch/arm/mach-mvebu/coherency.c
@@ -22,6 +22,10 @@
#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 "armada-370-xp.h"
/* Some functions in this file are called very early during SMP
@@ -31,16 +35,53 @@
* value matching its virtual mapping
*/
static void __iomem *coherency_base = ARMADA_370_XP_REGS_VIRT_BASE + 0x20200;
+static void __iomem *coherency_cpu_base;
+
+struct dma_map_ops armada_xp_dma_ops;
/* Coherency fabric registers */
#define COHERENCY_FABRIC_CTL_OFFSET 0x0
#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 */ },
};
+static inline void armada_xp_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);
+}
+
+dma_addr_t armada_xp_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)
+ armada_xp_sync_io_barrier();
+ return pfn_to_dma(dev, page_to_pfn(page)) + offset;
+}
+
+
+void armada_xp_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)
+ armada_xp_sync_io_barrier();
+}
+
+void armada_xp_dma_sync(struct device *dev, dma_addr_t dma_handle,
+ size_t size, enum dma_data_direction dir)
+{
+ if (dir != DMA_TO_DEVICE)
+ armada_xp_sync_io_barrier();
+}
+
int armada_xp_get_cpu_count(void)
{
int reg, cnt;
@@ -74,6 +115,42 @@ int armada_370_xp_set_cpu_coherent(unsigned int hw_cpu_id, int smp_group_id)
return 0;
}
+static int armada_xp_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, &armada_xp_dma_ops);
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block armada_xp_platform_nb = {
+ .notifier_call = armada_xp_platform_notifier,
+};
+
+void __init armada_370_xp_coherency_iocache_init(void)
+{
+ /* When the coherency fabric is available, the Armada XP and
+ * Aramada 370 are close to a coherent architecture, so we based
+ * our dma ops on the coherent one, and just changes the
+ * operations which need a arch io sync */
+ if (of_find_compatible_node(NULL, NULL, "marvell,coherency-fabric")) {
+ struct dma_map_ops *dma_ops = &armada_xp_dma_ops;
+ memcpy(dma_ops, &arm_coherent_dma_ops, sizeof(*dma_ops));
+ dma_ops->map_page = armada_xp_dma_map_page;
+ dma_ops->unmap_page = armada_xp_dma_unmap_page;
+ dma_ops->unmap_sg = arm_dma_ops.unmap_sg;
+ dma_ops->sync_single_for_cpu = armada_xp_dma_sync;
+ dma_ops->sync_single_for_device = armada_xp_dma_sync;
+ dma_ops->sync_sg_for_cpu = arm_dma_ops.sync_sg_for_cpu;
+ dma_ops->sync_sg_for_device = arm_dma_ops.sync_sg_for_device;
+ }
+ bus_register_notifier(&platform_bus_type, &armada_xp_platform_nb);
+}
+
int __init armada_370_xp_coherency_init(void)
{
struct device_node *np;
@@ -82,7 +159,17 @@ int __init armada_370_xp_coherency_init(void)
if (np) {
pr_info("Initializing Coherency fabric\n");
coherency_base = of_iomap(np, 0);
+ coherency_cpu_base = of_iomap(np, 1);
+ }
+#ifndef CONFIG_SMP
+ if (coherency_base) {
+ /* In UP case, cpu coherency is enabled here, in SMP case cpu
+ * coherency is enabled for each CPU by
+ * armada_xp_smp_prepare_cpus() in platsmp.c */
+ int hw_cpuid = cpu_logical_map(smp_processor_id());
+ armada_370_xp_set_cpu_coherent(hw_cpuid, 0);
}
+#endif
return 0;
}
diff --git a/arch/arm/mach-mvebu/common.h b/arch/arm/mach-mvebu/common.h
index 86484bb..fff952e 100644
--- a/arch/arm/mach-mvebu/common.h
+++ b/arch/arm/mach-mvebu/common.h
@@ -23,6 +23,8 @@ void armada_370_xp_handle_irq(struct pt_regs *regs);
void armada_xp_cpu_die(unsigned int cpu);
+void armada_370_xp_coherency_iocache_init(void);
+
int armada_370_xp_coherency_init(void);
int armada_370_xp_pmsu_init(void);
void armada_xp_secondary_startup(void);
--
1.7.9.5
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