On 6/13/18 12:54 AM, Sanyog Kale wrote:
On Tue, Jun 12, 2018 at 02:12:46PM -0500, Pierre-Louis Bossart wrote:
On 06/12/2018 05:53 AM, Shreyas NC wrote:
From: Vinod Koul <vkoul@xxxxxxxxxx>
For each SoundWire stream operation, we need to parse master
list and operate upon all master runtime.
This patch does the boilerplate conversion of stream handling
>from single master runtime to handle a list of master runtime.
Signed-off-by: Sanyog Kale <sanyog.r.kale@xxxxxxxxx>
Signed-off-by: Vinod Koul <vkoul@xxxxxxxxxx>
Signed-off-by: Shreyas NC <shreyas.nc@xxxxxxxxx>
---
drivers/soundwire/stream.c | 308 +++++++++++++++++++++++++-----------------
include/linux/soundwire/sdw.h | 2 -
2 files changed, 185 insertions(+), 125 deletions(-)
diff --git a/drivers/soundwire/stream.c b/drivers/soundwire/stream.c
index eb942c6..36506a7 100644
--- a/drivers/soundwire/stream.c
+++ b/drivers/soundwire/stream.c
@@ -681,35 +681,44 @@ static int sdw_bank_switch(struct sdw_bus *bus)
static int do_bank_switch(struct sdw_stream_runtime *stream)
{
- struct sdw_master_runtime *m_rt = stream->m_rt;
+ struct sdw_master_runtime *m_rt = NULL;
const struct sdw_master_ops *ops;
- struct sdw_bus *bus = m_rt->bus;
+ struct sdw_bus *bus = NULL;
int ret = 0;
- ops = bus->ops;
- /* Pre-bank switch */
- if (ops->pre_bank_switch) {
- ret = ops->pre_bank_switch(bus);
+ list_for_each_entry(m_rt, &stream->master_list, stream_node) {
+ bus = m_rt->bus;
+ ops = bus->ops;
+
+ /* Pre-bank switch */
+ if (ops->pre_bank_switch) {
+ ret = ops->pre_bank_switch(bus);
+ if (ret < 0) {
+ dev_err(bus->dev,
+ "Pre bank switch op failed: %d", ret);
+ return ret;
+ }
+ }
+
+ /* Bank switch */
+ ret = sdw_bank_switch(bus);
if (ret < 0) {
- dev_err(bus->dev, "Pre bank switch op failed: %d", ret);
+ dev_err(bus->dev, "Bank switch failed: %d", ret);
return ret;
}
You probably want to add a comment that in multi-link operation the actual
bank_switch happens later and is done in a synchronized manner. This is lost
if you just move code around and move the bank_switch into a loop.
I am actually no longer clear just looking at this code on when the
bank_switch happens (i know we've discussed this before but I am trying to
find out just based on this v2 instead of projecting how I think it should
work):
In Patch 6/6 it's pretty obvious that the bank switch happens when the
SyncGO bit is set, but there is no comment or explanation on how we reach
the intel_post_bank_switch() routine once for all masters handling a stream
when everything is based on loops. Clearly the intel_pre_bank_switch is
called multiple times (once per master), I guess I am missing what the
trigger is for the intel_post_bank_switch() routine to be invoked?
Hi Pierre,
To answer your last question, do_bank_switch is where we perform all the
bank switch operations.
In first loop for Master(s) involved in stream, ops->pre_bank_switch and
bank_switch is performed. In 2nd loop for Master(s) involved in stream,
ops->post_bank_switch and wait for bank switch is performed.
Assuming a stream with Master 1 and Master 2, the go_sync bit will be
set in Master 1 intel_post_bank_switch call which will trigger bank
switch for both the Master's. The Master 2 intel_post_bank_switch call
will just return as it will won't see CMDSYNC bit set for any Master(s).
Makes sense, thanks for taking the time to provide the details I didn't
remember.
Sreyas, if you could add a bit of information on this it'd be a good
thing - specifically the expectation is that the bank switch is
triggered by the first master in the master_list loop while others just
return without doing anything.
}
- /* Bank switch */
- ret = sdw_bank_switch(bus);
- if (ret < 0) {
- dev_err(bus->dev, "Bank switch failed: %d", ret);
- return ret;
- }
-
/* Post-bank switch */
- if (ops->post_bank_switch) {
- ret = ops->post_bank_switch(bus);
- if (ret < 0) {
- dev_err(bus->dev,
+ list_for_each_entry(m_rt, &stream->master_list, stream_node) {
+ bus = m_rt->bus;
+ ops = bus->ops;
+ if (ops->post_bank_switch) {
+ ret = ops->post_bank_switch(bus);
+ if (ret < 0) {
+ dev_err(bus->dev,
"Post bank switch op failed: %d", ret);
+ }
}
}
};
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