intel_th: msu-sink: An example msu buffer "sink"

This patch adds an example MSU buffer "sink", which consumes trace
data from MSC buffers.

Functionally, it acts similarly to "multi" mode with automatic window
switching.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20190705141425.19894-3-alexander.shishkin@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexander Shishkin 2019-07-05 17:14:22 +03:00 committed by Greg Kroah-Hartman
parent 615c164da0
commit f220df66f6
2 changed files with 119 additions and 0 deletions

View File

@ -20,3 +20,6 @@ intel_th_msu-y := msu.o
obj-$(CONFIG_INTEL_TH_PTI) += intel_th_pti.o
intel_th_pti-y := pti.o
obj-$(CONFIG_INTEL_TH_MSU) += intel_th_msu_sink.o
intel_th_msu_sink-y := msu-sink.o

View File

@ -0,0 +1,116 @@
// SPDX-License-Identifier: GPL-2.0
/*
* An example software sink buffer for Intel TH MSU.
*
* Copyright (C) 2019 Intel Corporation.
*/
#include <linux/intel_th.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#define MAX_SGTS 16
struct msu_sink_private {
struct device *dev;
struct sg_table **sgts;
unsigned int nr_sgts;
};
static void *msu_sink_assign(struct device *dev, int *mode)
{
struct msu_sink_private *priv;
priv = kzalloc(sizeof(*priv), GFP_KERNEL);
if (!priv)
return NULL;
priv->sgts = kcalloc(MAX_SGTS, sizeof(void *), GFP_KERNEL);
if (!priv->sgts) {
kfree(priv);
return NULL;
}
priv->dev = dev;
*mode = MSC_MODE_MULTI;
return priv;
}
static void msu_sink_unassign(void *data)
{
struct msu_sink_private *priv = data;
kfree(priv->sgts);
kfree(priv);
}
/* See also: msc.c: __msc_buffer_win_alloc() */
static int msu_sink_alloc_window(void *data, struct sg_table **sgt, size_t size)
{
struct msu_sink_private *priv = data;
unsigned int nents;
struct scatterlist *sg_ptr;
void *block;
int ret, i;
if (priv->nr_sgts == MAX_SGTS)
return -ENOMEM;
nents = DIV_ROUND_UP(size, PAGE_SIZE);
ret = sg_alloc_table(*sgt, nents, GFP_KERNEL);
if (ret)
return -ENOMEM;
priv->sgts[priv->nr_sgts++] = *sgt;
for_each_sg((*sgt)->sgl, sg_ptr, nents, i) {
block = dma_alloc_coherent(priv->dev->parent->parent,
PAGE_SIZE, &sg_dma_address(sg_ptr),
GFP_KERNEL);
sg_set_buf(sg_ptr, block, PAGE_SIZE);
}
return nents;
}
/* See also: msc.c: __msc_buffer_win_free() */
static void msu_sink_free_window(void *data, struct sg_table *sgt)
{
struct msu_sink_private *priv = data;
struct scatterlist *sg_ptr;
int i;
for_each_sg(sgt->sgl, sg_ptr, sgt->nents, i) {
dma_free_coherent(priv->dev->parent->parent, PAGE_SIZE,
sg_virt(sg_ptr), sg_dma_address(sg_ptr));
}
sg_free_table(sgt);
priv->nr_sgts--;
}
static int msu_sink_ready(void *data, struct sg_table *sgt, size_t bytes)
{
struct msu_sink_private *priv = data;
intel_th_msc_window_unlock(priv->dev, sgt);
return 0;
}
static const struct msu_buffer sink_mbuf = {
.name = "sink",
.assign = msu_sink_assign,
.unassign = msu_sink_unassign,
.alloc_window = msu_sink_alloc_window,
.free_window = msu_sink_free_window,
.ready = msu_sink_ready,
};
module_intel_th_msu_buffer(sink_mbuf);
MODULE_LICENSE("GPL v2");