From 534224b958dfc5c7beca2542e27a094d64d66b1a Mon Sep 17 00:00:00 2001 From: Sudeep Holla Date: Fri, 19 Jan 2024 15:23:37 +0000 Subject: [PATCH] firmware: arm_scmi: Warn if domain frequency multiplier is 0 or rounded off When (sustained_freq_khz * 1000) is less than sustained_perf_level, the multiplier will be less than 1 and hence rounded down as 0. Similarly if it is not multiple of sustained_perf_level the dom_info->mult_factor will contain rounded down value and will end up impacting all the frequency calculations done using it. Add warning if and when the domain frequency multiplier is 0 or rounded down so that it gives a clue to get the firmware tables fixed. Suggested-by: Pierre Gondois Reviewed-by: Pierre Gondois Reviewed-by: Cristian Marussi Link: https://lore.kernel.org/r/20240119152338.3047620-1-sudeep.holla@arm.com Signed-off-by: Sudeep Holla --- drivers/firmware/arm_scmi/perf.c | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c index 211e8e0aef2c..9e7b1ee94940 100644 --- a/drivers/firmware/arm_scmi/perf.c +++ b/drivers/firmware/arm_scmi/perf.c @@ -270,15 +270,30 @@ scmi_perf_domain_attributes_get(const struct scmi_protocol_handle *ph, le32_to_cpu(attr->sustained_freq_khz); dom_info->sustained_perf_level = le32_to_cpu(attr->sustained_perf_level); + /* + * sustained_freq_khz = mult_factor * sustained_perf_level + * mult_factor must be non zero positive integer(not fraction) + */ if (!dom_info->sustained_freq_khz || !dom_info->sustained_perf_level || - dom_info->level_indexing_mode) + dom_info->level_indexing_mode) { /* CPUFreq converts to kHz, hence default 1000 */ dom_info->mult_factor = 1000; - else + } else { dom_info->mult_factor = (dom_info->sustained_freq_khz * 1000UL) / dom_info->sustained_perf_level; + if ((dom_info->sustained_freq_khz * 1000UL) % + dom_info->sustained_perf_level) + dev_warn(ph->dev, + "multiplier for domain %d rounded\n", + dom_info->id); + } + if (!dom_info->mult_factor) + dev_warn(ph->dev, + "Wrong sustained perf/frequency(domain %d)\n", + dom_info->id); + strscpy(dom_info->info.name, attr->name, SCMI_SHORT_NAME_MAX_SIZE); }