Add the support for Scatter-Gather mode to the etr-buf layer.
Since we now have two different modes, we choose the backend
based on a set of conditions, documented in the code.
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
Change since last version:
- New in this version, splitted from the original patch.
- No functional changes.
---
drivers/hwtracing/coresight/coresight-tmc-etr.c | 114 +++++++++++++++++++++++-
drivers/hwtracing/coresight/coresight-tmc.h | 1 +
2 files changed, 111 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index a0e504a..19955cf 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -516,7 +516,7 @@ static void tmc_etr_sg_table_populate(struct etr_sg_table *etr_table)
* @size - Total size of the data buffer
* @pages - Optional list of page virtual address
*/
-static struct etr_sg_table __maybe_unused *
+static struct etr_sg_table *
tmc_init_etr_sg_table(struct device *dev, int node,
unsigned long size, void **pages)
{
@@ -623,8 +623,86 @@ static const struct etr_buf_operations etr_flat_buf_ops = {
.get_data = tmc_etr_get_data_flat_buf,
};
+/*
+ * tmc_etr_alloc_sg_buf: Allocate an SG buf @etr_buf. Setup the parameters
+ * appropriately.
+ */
+static int tmc_etr_alloc_sg_buf(struct tmc_drvdata *drvdata,
+ struct etr_buf *etr_buf, int node,
+ void **pages)
+{
+ struct etr_sg_table *etr_table;
+
+ etr_table = tmc_init_etr_sg_table(drvdata->dev, node,
+ etr_buf->size, pages);
+ if (IS_ERR(etr_table))
+ return -ENOMEM;
+ etr_buf->hwaddr = etr_table->hwaddr;
+ etr_buf->mode = ETR_MODE_ETR_SG;
+ etr_buf->private = etr_table;
+ return 0;
+}
+
+static void tmc_etr_free_sg_buf(struct etr_buf *etr_buf)
+{
+ struct etr_sg_table *etr_table = etr_buf->private;
+
+ if (etr_table) {
+ tmc_free_sg_table(etr_table->sg_table);
+ kfree(etr_table);
+ }
+}
+
+static ssize_t tmc_etr_get_data_sg_buf(struct etr_buf *etr_buf, u64 offset,
+ size_t len, char **bufpp)
+{
+ struct etr_sg_table *etr_table = etr_buf->private;
+
+ return tmc_sg_table_get_data(etr_table->sg_table, offset, len, bufpp);
+}
+
+static void tmc_etr_sync_sg_buf(struct etr_buf *etr_buf, u64 rrp, u64 rwp)
+{
+ long r_offset, w_offset;
+ struct etr_sg_table *etr_table = etr_buf->private;
+ struct tmc_sg_table *table = etr_table->sg_table;
+
+ /* Convert hw address to offset in the buffer */
+ r_offset = tmc_sg_get_data_page_offset(table, rrp);
+ if (r_offset < 0) {
+ dev_warn(table->dev,
+ "Unable to map RRP %llx to offset\n", rrp);
+ etr_buf->len = 0;
+ return;
+ }
+
+ w_offset = tmc_sg_get_data_page_offset(table, rwp);
+ if (w_offset < 0) {
+ dev_warn(table->dev,
+ "Unable to map RWP %llx to offset\n", rwp);
+ etr_buf->len = 0;
+ return;
+ }
+
+ etr_buf->offset = r_offset;
+ if (etr_buf->full)
+ etr_buf->len = etr_buf->size;
+ else
+ etr_buf->len = ((w_offset < r_offset) ? etr_buf->size : 0) +
+ w_offset - r_offset;
+ tmc_sg_table_sync_data_range(table, r_offset, etr_buf->len);
+}
+
+static const struct etr_buf_operations etr_sg_buf_ops = {
+ .alloc = tmc_etr_alloc_sg_buf,
+ .free = tmc_etr_free_sg_buf,
+ .sync = tmc_etr_sync_sg_buf,
+ .get_data = tmc_etr_get_data_sg_buf,
+};
+
static const struct etr_buf_operations *etr_buf_ops[] = {
[ETR_MODE_FLAT] = &etr_flat_buf_ops,
+ [ETR_MODE_ETR_SG] = &etr_sg_buf_ops,
};
static inline int tmc_etr_mode_alloc_buf(int mode,
@@ -636,6 +714,7 @@ static inline int tmc_etr_mode_alloc_buf(int mode,
switch (mode) {
case ETR_MODE_FLAT:
+ case ETR_MODE_ETR_SG:
rc = etr_buf_ops[mode]->alloc(drvdata, etr_buf, node, pages);
if (!rc)
etr_buf->ops = etr_buf_ops[mode];
@@ -657,17 +736,38 @@ static struct etr_buf *tmc_alloc_etr_buf(struct tmc_drvdata *drvdata,
ssize_t size, int flags,
int node, void **pages)
{
- int rc = 0;
+ int rc = -ENOMEM;
+ bool has_etr_sg, has_iommu;
struct etr_buf *etr_buf;
+ has_etr_sg = tmc_etr_has_cap(drvdata, TMC_ETR_SG);
+ has_iommu = iommu_get_domain_for_dev(drvdata->dev);
+
etr_buf = kzalloc(sizeof(*etr_buf), GFP_KERNEL);
if (!etr_buf)
return ERR_PTR(-ENOMEM);
etr_buf->size = size;
- rc = tmc_etr_mode_alloc_buf(ETR_MODE_FLAT, drvdata,
- etr_buf, node, pages);
+ /*
+ * If we have to use an existing list of pages, we cannot reliably
+ * use a contiguous DMA memory (even if we have an IOMMU). Otherwise,
+ * we use the contiguous DMA memory if at least one of the following
+ * conditions is true:
+ * a) The ETR cannot use Scatter-Gather.
+ * b) we have a backing IOMMU
+ * c) The requested memory size is smaller (< 1M).
+ *
+ * Fallback to available mechanisms.
+ *
+ */
+ if (!pages &&
+ (!has_etr_sg || has_iommu || size < SZ_1M))
+ rc = tmc_etr_mode_alloc_buf(ETR_MODE_FLAT, drvdata,
+ etr_buf, node, pages);
+ if (rc && has_etr_sg)
+ rc = tmc_etr_mode_alloc_buf(ETR_MODE_ETR_SG, drvdata,
+ etr_buf, node, pages);
if (rc) {
kfree(etr_buf);
return ERR_PTR(rc);
@@ -761,6 +861,12 @@ static void tmc_etr_enable_hw(struct tmc_drvdata *drvdata)
axictl |= TMC_AXICTL_ARCACHE_OS;
}
+ if (etr_buf->mode == ETR_MODE_ETR_SG) {
+ if (WARN_ON(!tmc_etr_has_cap(drvdata, TMC_ETR_SG)))
+ return;
+ axictl |= TMC_AXICTL_SCT_GAT_MODE;
+ }
+
writel_relaxed(axictl, drvdata->base + TMC_AXICTL);
tmc_write_dba(drvdata, etr_buf->hwaddr);
/*
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 39ed306..eeeba48 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -125,6 +125,7 @@ enum tmc_mem_intf_width {
enum etr_mode {
ETR_MODE_FLAT, /* Uses contiguous flat buffer */
+ ETR_MODE_ETR_SG, /* Uses in-built TMC ETR SG mechanism */
};
struct etr_buf_operations;
--
2.7.4
--
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