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Message-Id: <1454313529-8860-4-git-send-email-zhang.chunyan@linaro.org>
Date: Mon, 1 Feb 2016 15:58:46 +0800
From: Chunyan Zhang <zhang.chunyan@...aro.org>
To: mathieu.poirier@...aro.org, alexander.shishkin@...ux.intel.com
Cc: robh@...nel.org, broonie@...nel.org, pratikp@...eaurora.org,
nicolas.guion@...com, corbet@....net, mark.rutland@....com,
zhang.lyra@...il.com, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, linux-api@...r.kernel.orgi,
linux-doc@...r.kernel.org
Subject: [PATCH 3/6] stm class: provision for statically assigned masterIDs
From: Mathieu Poirier <mathieu.poirier@...aro.org>
Some architecture like ARM assign masterIDs statically at the HW design
phase, making masterID manipulation in the generic STM core irrelevant.
This patch adds a new 'mstatic' flag to struct stm_data that tells the
core that this specific STM device doesn't need explicit masterID
management. In the core sw_start/end of masterID are set to '1',
i.e there is only one masterID to deal with.
Also this patch depends on [1], so that the number of masterID
is '1' too.
Finally the lower and upper bound for masterIDs as presented
in ($SYSFS)/class/stm/XYZ.stm/masters and
($SYSFS)/../stp-policy/XYZ.stm.my_policy/some_device/masters
are set to '-1'. That way users can't confuse them with
architecture where masterID management is required (where any
other value would be valid).
[1] https://lkml.org/lkml/2015/12/22/348
Signed-off-by: Mathieu Poirier <mathieu.poirier@...aro.org>
Signed-off-by: Chunyan Zhang <zhang.chunyan@...aro.org>
---
drivers/hwtracing/stm/core.c | 18 ++++++++++++++++--
drivers/hwtracing/stm/policy.c | 19 +++++++++++++++++--
include/linux/stm.h | 8 ++++++++
3 files changed, 41 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/stm/core.c b/drivers/hwtracing/stm/core.c
index 86bb4e3..cd3dc19 100644
--- a/drivers/hwtracing/stm/core.c
+++ b/drivers/hwtracing/stm/core.c
@@ -44,9 +44,15 @@ static ssize_t masters_show(struct device *dev,
char *buf)
{
struct stm_device *stm = to_stm_device(dev);
- int ret;
+ int ret, sw_start, sw_end;
+
+ sw_start = stm->data->sw_start;
+ sw_end = stm->data->sw_end;
- ret = sprintf(buf, "%u %u\n", stm->data->sw_start, stm->data->sw_end);
+ if (stm->data->mstatic)
+ sw_start = sw_end = STM_STATIC_MASTERID;
+
+ ret = sprintf(buf, "%d %d\n", sw_start, sw_end);
return ret;
}
@@ -629,7 +635,15 @@ int stm_register_device(struct device *parent, struct stm_data *stm_data,
if (!stm_data->packet || !stm_data->sw_nchannels)
return -EINVAL;
+ /*
+ * MasterIDs are statically set in HW. As such the core is
+ * using a single master for interaction with this device.
+ */
+ if (stm_data->mstatic)
+ stm_data->sw_start = stm_data->sw_end = 1;
+
nmasters = stm_data->sw_end - stm_data->sw_start;
+
stm = kzalloc(sizeof(*stm) + nmasters * sizeof(void *), GFP_KERNEL);
if (!stm)
return -ENOMEM;
diff --git a/drivers/hwtracing/stm/policy.c b/drivers/hwtracing/stm/policy.c
index 691686e..7e70ca2 100644
--- a/drivers/hwtracing/stm/policy.c
+++ b/drivers/hwtracing/stm/policy.c
@@ -80,10 +80,17 @@ static ssize_t
stp_policy_node_masters_show(struct config_item *item, char *page)
{
struct stp_policy_node *policy_node = to_stp_policy_node(item);
+ struct stm_device *stm = policy_node->policy->stm;
+ int first_master, last_master;
ssize_t count;
- count = sprintf(page, "%u %u\n", policy_node->first_master,
- policy_node->last_master);
+ first_master = policy_node->first_master;
+ last_master = policy_node->last_master;
+
+ if (stm && stm->data->mstatic)
+ first_master = last_master = STM_STATIC_MASTERID;
+
+ count = sprintf(page, "%d %d\n", first_master, last_master);
return count;
}
@@ -106,6 +113,13 @@ stp_policy_node_masters_store(struct config_item *item, const char *page,
if (!stm)
goto unlock;
+ /*
+ * masterIDs are statically allocated in HW, no point in trying to
+ * change their values.
+ */
+ if (stm->data->mstatic)
+ goto unlock;
+
/* must be within [sw_start..sw_end], which is an inclusive range */
if (first > INT_MAX || last > INT_MAX || first > last ||
first < stm->data->sw_start ||
@@ -325,6 +339,7 @@ stp_policies_make(struct config_group *group, const char *name)
* number of dot(s) are found in the <device_name>, the
* first matched STM device name would be extracted.
*/
+
for (p = devname; ; p++) {
p = strchr(p, '.');
if (!p) {
diff --git a/include/linux/stm.h b/include/linux/stm.h
index f351d62..c9712a7 100644
--- a/include/linux/stm.h
+++ b/include/linux/stm.h
@@ -18,6 +18,11 @@
#include <linux/device.h>
/**
+ * The masterIDs are statically set in hardware and can't be queried
+ */
+#define STM_STATIC_MASTERID -1
+
+/**
* enum stp_packet_type - STP packets that an STM driver sends
*/
enum stp_packet_type {
@@ -46,6 +51,8 @@ struct stm_device;
* struct stm_data - STM device description and callbacks
* @name: device name
* @stm: internal structure, only used by stm class code
+ * @mstatic: true if masterIDs are assigned in HW. If so @sw_start
+ * and @sw_end are set to '1' by the core.
* @sw_start: first STP master available to software
* @sw_end: last STP master available to software
* @sw_nchannels: number of STP channels per master
@@ -71,6 +78,7 @@ struct stm_device;
struct stm_data {
const char *name;
struct stm_device *stm;
+ bool mstatic;
unsigned int sw_start;
unsigned int sw_end;
unsigned int sw_nchannels;
--
1.9.1
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