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authorAlexander Shishkin <alexander.shishkin@linux.intel.com>2019-07-05 17:14:22 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-07-25 13:03:18 +0200
commitf220df66f67684246ae1bf4a4e479efc7c2f325a (patch)
tree5fc0cc3a1a6274535c8f729f8c2eaae2e8ce70b3 /drivers/hwtracing
parent615c164da0eb42cbfb1688cb429cc4d5039db5d8 (diff)
downloadlinux-f220df66f67684246ae1bf4a4e479efc7c2f325a.tar.bz2
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>
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r--drivers/hwtracing/intel_th/Makefile3
-rw-r--r--drivers/hwtracing/intel_th/msu-sink.c116
2 files changed, 119 insertions, 0 deletions
diff --git a/drivers/hwtracing/intel_th/Makefile b/drivers/hwtracing/intel_th/Makefile
index d9252fa8d9ca..b63eb8f309ad 100644
--- a/drivers/hwtracing/intel_th/Makefile
+++ b/drivers/hwtracing/intel_th/Makefile
@@ -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
diff --git a/drivers/hwtracing/intel_th/msu-sink.c b/drivers/hwtracing/intel_th/msu-sink.c
new file mode 100644
index 000000000000..2c7f5116be12
--- /dev/null
+++ b/drivers/hwtracing/intel_th/msu-sink.c
@@ -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");