CoreSight STM device allows direct mapping of the channel regions to
userspace for zero-copy writing. To support this ability, the STM
framework has provided a hook 'mmio_addr', this patch just implemented
this hook for CoreSight STM.
This patch also added an item into 'channel_space' to save the physical
base address of channel region which mmap operation needs to know.
Signed-off-by: Chunyan Zhang <zhang.chun...@linaro.org>
---
drivers/hwtracing/coresight/coresight-stm.c | 22 ++++++++++++++++++++++
1 file changed, 22 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-stm.c
b/drivers/hwtracing/coresight/coresight-stm.c
index 73be58a..482c8bb 100644
--- a/drivers/hwtracing/coresight/coresight-stm.c
+++ b/drivers/hwtracing/coresight/coresight-stm.c
@@ -105,10 +105,12 @@ module_param_named(
/**
* struct channel_space - central management entity for extended ports
* @base: memory mapped base address where channels start.
+ * @phys: physical base address of channel region.
* @guaraneed: is the channel delivery guaranteed.
*/
struct channel_space {
void __iomem *base;
+ phys_addr_t phys;
unsigned long *guaranteed;
};
@@ -356,6 +358,23 @@ static void stm_generic_unlink(struct stm_data *stm_data,
stm_disable(drvdata->csdev);
}
+static phys_addr_t
+stm_mmio_addr(struct stm_data *stm_data, unsigned int master,
+ unsigned int channel, unsigned int nr_chans)
+{
+ struct stm_drvdata *drvdata = container_of(stm_data,
+ struct stm_drvdata, stm);
+ phys_addr_t addr;
+
+ addr = drvdata->chs.phys + channel * BYTES_PER_CHANNEL;
+
+ if (offset_in_page(addr) ||
+ offset_in_page(nr_chans * BYTES_PER_CHANNEL))
+ return 0;
+
+ return addr;
+}
+
static long stm_generic_set_options(struct stm_data *stm_data,
unsigned int master,
unsigned int channel,
@@ -761,7 +780,9 @@ static void stm_init_generic_data(struct stm_drvdata
*drvdata)
drvdata->stm.sw_end = 1;
drvdata->stm.hw_override = true;
drvdata->stm.sw_nchannels = drvdata->numsp;
+ drvdata->stm.sw_mmiosz = BYTES_PER_CHANNEL;
drvdata->stm.packet = stm_generic_packet;
+ drvdata->stm.mmio_addr = stm_mmio_addr;
drvdata->stm.link = stm_generic_link;
drvdata->stm.unlink = stm_generic_unlink;
drvdata->stm.set_options = stm_generic_set_options;
@@ -808,6 +829,7 @@ static int stm_probe(struct amba_device *adev, const struct
amba_id *id)
ret = stm_get_resource_byname(np, "stm-stimulus-base", &ch_res);
if (ret)
return ret;
+ drvdata->chs.phys = ch_res.start;
base = devm_ioremap_resource(dev, &ch_res);
if (IS_ERR(base))
--
1.9.1
