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// SPDX-License-Identifier: GPL-2.0-only
/*
* RISC-V specific functions to support DMA for non-coherent devices
*
* Copyright (c) 2021 Western Digital Corporation or its affiliates.
*/
#include <linux/dma-direct.h>
#include <linux/dma-map-ops.h>
#include <linux/mm.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <asm/cacheflush.h>
unsigned int riscv_cbom_block_size;
EXPORT_SYMBOL_GPL(riscv_cbom_block_size);
static bool noncoherent_supported;
void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
void *vaddr = phys_to_virt(paddr);
switch (dir) {
case DMA_TO_DEVICE:
ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size);
break;
case DMA_FROM_DEVICE:
ALT_CMO_OP(clean, vaddr, size, riscv_cbom_block_size);
break;
case DMA_BIDIRECTIONAL:
ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size);
break;
default:
break;
}
}
void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
enum dma_data_direction dir)
{
void *vaddr = phys_to_virt(paddr);
switch (dir) {
case DMA_TO_DEVICE:
break;
case DMA_FROM_DEVICE:
case DMA_BIDIRECTIONAL:
ALT_CMO_OP(flush, vaddr, size, riscv_cbom_block_size);
break;
default:
break;
}
}
void arch_dma_prep_coherent(struct page *page, size_t size)
{
void *flush_addr = page_address(page);
ALT_CMO_OP(flush, flush_addr, size, riscv_cbom_block_size);
}
void arch_setup_dma_ops(struct device *dev, u64 dma_base, u64 size,
const struct iommu_ops *iommu, bool coherent)
{
WARN_TAINT(!coherent && riscv_cbom_block_size > ARCH_DMA_MINALIGN,
TAINT_CPU_OUT_OF_SPEC,
"%s %s: ARCH_DMA_MINALIGN smaller than riscv,cbom-block-size (%d < %d)",
dev_driver_string(dev), dev_name(dev),
ARCH_DMA_MINALIGN, riscv_cbom_block_size);
WARN_TAINT(!coherent && !noncoherent_supported, TAINT_CPU_OUT_OF_SPEC,
"%s %s: device non-coherent but no non-coherent operations supported",
dev_driver_string(dev), dev_name(dev));
dev->dma_coherent = coherent;
}
#ifdef CONFIG_RISCV_ISA_ZICBOM
void riscv_init_cbom_blocksize(void)
{
struct device_node *node;
unsigned long cbom_hartid;
u32 val, probed_block_size;
int ret;
probed_block_size = 0;
for_each_of_cpu_node(node) {
unsigned long hartid;
ret = riscv_of_processor_hartid(node, &hartid);
if (ret)
continue;
/* set block-size for cbom extension if available */
ret = of_property_read_u32(node, "riscv,cbom-block-size", &val);
if (ret)
continue;
if (!probed_block_size) {
probed_block_size = val;
cbom_hartid = hartid;
} else {
if (probed_block_size != val)
pr_warn("cbom-block-size mismatched between harts %lu and %lu\n",
cbom_hartid, hartid);
}
}
if (probed_block_size)
riscv_cbom_block_size = probed_block_size;
}
#endif
void riscv_noncoherent_supported(void)
{
WARN(!riscv_cbom_block_size,
"Non-coherent DMA support enabled without a block size\n");
noncoherent_supported = true;
}
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