ASoC: Intel: Skylake: Make MCPS and CPS params obsolete

As per FW Interface Modules Configuration, init instance IPC request
requires base initial module configuration. This configuration structure
is made of:
- cpc (chunks per cycle)
- ibs (input buffer size)
- obs (output buffer size)
- is_pages (memory pages required)
- audio_fmt (self explanatory)

Skylake topology accepts following tokens: MCPS, CPS and CPC. All of
these are directly connected. Moreover, assigning one of these allows
to calculate the remaining two. In simplest scenario and assuming 1ms
scheduling, following is true:

CPS = CPC times 1000
MCPS = CPS times 1000 000
Note: these calculations vary depending on scenario and scheduling
requirements.

Given the current implementation, userspace is allowed to provide
different values for all three causing informational chaos. On top of
that, struct skl_base_cfg which represents base module configuration,
incorrectly takes CPS param instead of CPC.

This ambiguity may lead to user unintentionally providing improper
values to DSP firmware and thus impacting module scheduling in
unexpected fashion. Fix by making MCPS and CPS topology params obsolete
and relying solely on CPC value.

Signed-off-by: Cezary Rojewski <cezary.rojewski@intel.com>
Link: https://lore.kernel.org/r/20190723145854.8527-7-cezary.rojewski@intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 4 insertions, 2 deletions

diff --git a/sound/soc/intel/skylake/skl-debug.c b/sound/soc/intel/skylake/skl-debug.c
index c43aa4081232..fb232428109f 100644
--- a/sound/soc/intel/skylake/skl-debug.c
+++ b/sound/soc/intel/skylake/skl-debug.c
@@ -66,6 +66,8 @@ static ssize_t module_read(struct file *file, char __user *user_buf,
 			   size_t count, loff_t *ppos)
 {
 	struct skl_module_cfg *mconfig = file->private_data;
+	struct skl_module *module = mconfig->module;
+	struct skl_module_res *res = &module->resources[mconfig->res_idx];
 	char *buf;
 	ssize_t ret;
 
@@ -79,8 +81,8 @@ static ssize_t module_read(struct file *file, char __user *user_buf,
 			mconfig->id.pvt_id);
 
 	ret += snprintf(buf + ret, MOD_BUF - ret,
-			"Resources:\n\tMCPS %#x\n\tIBS %#x\n\tOBS %#x\t\n",
-			mconfig->mcps, mconfig->ibs, mconfig->obs);
+			"Resources:\n\tCPC %#x\n\tIBS %#x\n\tOBS %#x\t\n",
+			res->cpc, res->ibs, res->obs);
 
 	ret += snprintf(buf + ret, MOD_BUF - ret,
 			"Module data:\n\tCore %d\n\tIn queue %d\n\t"