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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright(c) 2016 - 2018 Intel Corporation. All rights reserved.
*/
#include <linux/dma-mapping.h>
#include <linux/mei.h>
#include "mei_dev.h"
/**
* mei_dmam_dscr_alloc() - allocate a managed coherent buffer
* for the dma descriptor
* @dev: mei_device
* @dscr: dma descriptor
*
* Return:
* * 0 - on success or zero allocation request
* * -EINVAL - if size is not power of 2
* * -ENOMEM - of allocation has failed
*/
static int mei_dmam_dscr_alloc(struct mei_device *dev,
struct mei_dma_dscr *dscr)
{
if (!dscr->size)
return 0;
if (WARN_ON(!is_power_of_2(dscr->size)))
return -EINVAL;
if (dscr->vaddr)
return 0;
dscr->vaddr = dmam_alloc_coherent(dev->dev, dscr->size, &dscr->daddr,
GFP_KERNEL);
if (!dscr->vaddr)
return -ENOMEM;
return 0;
}
/**
* mei_dmam_dscr_free() - free a managed coherent buffer
* from the dma descriptor
* @dev: mei_device
* @dscr: dma descriptor
*/
static void mei_dmam_dscr_free(struct mei_device *dev,
struct mei_dma_dscr *dscr)
{
if (!dscr->vaddr)
return;
dmam_free_coherent(dev->dev, dscr->size, dscr->vaddr, dscr->daddr);
dscr->vaddr = NULL;
}
/**
* mei_dmam_ring_free() - free dma ring buffers
* @dev: mei device
*/
void mei_dmam_ring_free(struct mei_device *dev)
{
int i;
for (i = 0; i < DMA_DSCR_NUM; i++)
mei_dmam_dscr_free(dev, &dev->dr_dscr[i]);
}
/**
* mei_dmam_ring_alloc() - allocate dma ring buffers
* @dev: mei device
*
* Return: -ENOMEM on allocation failure 0 otherwise
*/
int mei_dmam_ring_alloc(struct mei_device *dev)
{
int i;
for (i = 0; i < DMA_DSCR_NUM; i++)
if (mei_dmam_dscr_alloc(dev, &dev->dr_dscr[i]))
goto err;
return 0;
err:
mei_dmam_ring_free(dev);
return -ENOMEM;
}
/**
* mei_dma_ring_is_allocated() - check if dma ring is allocated
* @dev: mei device
*
* Return: true if dma ring is allocated
*/
bool mei_dma_ring_is_allocated(struct mei_device *dev)
{
return !!dev->dr_dscr[DMA_DSCR_HOST].vaddr;
}
static inline
struct hbm_dma_ring_ctrl *mei_dma_ring_ctrl(struct mei_device *dev)
{
return (struct hbm_dma_ring_ctrl *)dev->dr_dscr[DMA_DSCR_CTRL].vaddr;
}
/**
* mei_dma_ring_reset() - reset the dma control block
* @dev: mei device
*/
void mei_dma_ring_reset(struct mei_device *dev)
{
struct hbm_dma_ring_ctrl *ctrl = mei_dma_ring_ctrl(dev);
if (!ctrl)
return;
memset(ctrl, 0, sizeof(*ctrl));
}
/**
* mei_dma_copy_from() - copy from dma ring into buffer
* @dev: mei device
* @buf: data buffer
* @offset: offset in slots.
* @n: number of slots to copy.
*/
static size_t mei_dma_copy_from(struct mei_device *dev, unsigned char *buf,
u32 offset, u32 n)
{
unsigned char *dbuf = dev->dr_dscr[DMA_DSCR_DEVICE].vaddr;
size_t b_offset = offset << 2;
size_t b_n = n << 2;
memcpy(buf, dbuf + b_offset, b_n);
return b_n;
}
/**
* mei_dma_ring_read() - read data from the ring
* @dev: mei device
* @buf: buffer to read into: may be NULL in case of droping the data.
* @len: length to read.
*/
void mei_dma_ring_read(struct mei_device *dev, unsigned char *buf, u32 len)
{
struct hbm_dma_ring_ctrl *ctrl = mei_dma_ring_ctrl(dev);
u32 dbuf_depth;
u32 rd_idx, rem, slots;
if (WARN_ON(!ctrl))
return;
dev_dbg(dev->dev, "reading from dma %u bytes\n", len);
if (!len)
return;
dbuf_depth = dev->dr_dscr[DMA_DSCR_DEVICE].size >> 2;
rd_idx = READ_ONCE(ctrl->dbuf_rd_idx) & (dbuf_depth - 1);
slots = mei_data2slots(len);
/* if buf is NULL we drop the packet by advancing the pointer.*/
if (!buf)
goto out;
if (rd_idx + slots > dbuf_depth) {
buf += mei_dma_copy_from(dev, buf, rd_idx, dbuf_depth - rd_idx);
rem = slots - (dbuf_depth - rd_idx);
rd_idx = 0;
} else {
rem = slots;
}
mei_dma_copy_from(dev, buf, rd_idx, rem);
out:
WRITE_ONCE(ctrl->dbuf_rd_idx, ctrl->dbuf_rd_idx + slots);
}
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