public inbox for devel@edk2.groups.io
 help / color / mirror / Atom feed
* [PATCH v2] ArmPkg/ArmScmiDxe: Fix the calculation of RequiredArraySize in ClockDescribeRates()
@ 2023-02-03 14:23 Sudeep Holla
  2023-02-03 14:53 ` [edk2-devel] " Sami Mujawar
  0 siblings, 1 reply; 3+ messages in thread
From: Sudeep Holla @ 2023-02-03 14:23 UTC (permalink / raw)
  To: devel
  Cc: Sudeep Holla, Leif Lindholm, Ard Biesheuvel, Pierre Gondois,
	Girish Pathak, Jeff Brasen, Pierre Gondois, Sami Mujawar

As per the SCMI specification, section CLOCK_DESCRIBE_RATES mentions
that the value of num_rates_flags[11:0] in the response must be 3 if
the return format is the triplet. Due to the buggy firmware, this was
not noticed for long time. The firmware is now fixed resulting in
ClockDescribeRates() to fail with "Buffer Too Small" error as the
RequiredArraySize gets miscalculated as 72 instead of 24.

Fix the issue by reusing the logic for both the return format which
must work if num_rates_flags has correct value as expected from the
specification.

Cc: Pierre Gondois <Pierre.Gondois@arm.com>
Cc: Girish Pathak <girish.pathak@arm.com>
Cc: Jeff Brasen <jbrasen@nvidia.com>
Reviewed-by: Pierre Gondois <pierre.gondois@arm.com>
Tested-by: Pierre Gondois <pierre.gondois@arm.com>
Reported-by: Sami Mujawar <sami.mujawar@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
---
 ArmPkg/Drivers/ArmScmiDxe/ScmiClockProtocol.c | 35 ++++++++-----------
 1 file changed, 14 insertions(+), 21 deletions(-)

v1->v2:
	- Removed the unnecessary and incorrect loop to populate
	  the clock rate triplets(as suggested by Pierre)

Note the real delta is just 7 lines deletion when viewed with ignored
spacechanges.

diff --git a/ArmPkg/Drivers/ArmScmiDxe/ScmiClockProtocol.c b/ArmPkg/Drivers/ArmScmiDxe/ScmiClockProtocol.c
index 12a7e6df5d43..f092208a6601 100644
--- a/ArmPkg/Drivers/ArmScmiDxe/ScmiClockProtocol.c
+++ b/ArmPkg/Drivers/ArmScmiDxe/ScmiClockProtocol.c
@@ -236,12 +236,7 @@ ClockDescribeRates (
       *TotalRates = NUM_RATES (DescribeRates->NumRatesFlags)
                     + NUM_REMAIN_RATES (DescribeRates->NumRatesFlags);
 
-      if (*Format == ScmiClockRateFormatDiscrete) {
-        RequiredArraySize = (*TotalRates) * sizeof (UINT64);
-      } else {
-        // We need to return triplet of 64 bit value for each rate
-        RequiredArraySize = (*TotalRates) * 3 * sizeof (UINT64);
-      }
+      RequiredArraySize = (*TotalRates) * sizeof (UINT64);
 
       if (RequiredArraySize > (*RateArraySize)) {
         *RateArraySize = RequiredArraySize;
@@ -259,23 +254,21 @@ ClockDescribeRates (
           ConvertTo64Bit (Rate->Low, Rate->High);
       }
     } else {
-      for (RateNo = 0; RateNo < NUM_RATES (DescribeRates->NumRatesFlags); RateNo++) {
-        // Linear clock rates from minimum to maximum in steps
-        // Minimum clock rate.
-        Rate                                    = &DescribeRates->Rates[RateOffset++];
-        RateArray[RateIndex].ContinuousRate.Min =
-          ConvertTo64Bit (Rate->Low, Rate->High);
+      // Linear clock rates from minimum to maximum in steps
+      // Minimum clock rate.
+      Rate                                    = &DescribeRates->Rates[RateOffset++];
+      RateArray[RateIndex].ContinuousRate.Min =
+        ConvertTo64Bit (Rate->Low, Rate->High);
 
-        Rate = &DescribeRates->Rates[RateOffset++];
-        // Maximum clock rate.
-        RateArray[RateIndex].ContinuousRate.Max =
-          ConvertTo64Bit (Rate->Low, Rate->High);
+      Rate = &DescribeRates->Rates[RateOffset++];
+      // Maximum clock rate.
+      RateArray[RateIndex].ContinuousRate.Max =
+        ConvertTo64Bit (Rate->Low, Rate->High);
 
-        Rate = &DescribeRates->Rates[RateOffset++];
-        // Step.
-        RateArray[RateIndex++].ContinuousRate.Step =
-          ConvertTo64Bit (Rate->Low, Rate->High);
-      }
+      Rate = &DescribeRates->Rates[RateOffset++];
+      // Step.
+      RateArray[RateIndex++].ContinuousRate.Step =
+        ConvertTo64Bit (Rate->Low, Rate->High);
     }
   } while (NUM_REMAIN_RATES (DescribeRates->NumRatesFlags) != 0);
 
-- 
2.39.1


^ permalink raw reply related	[flat|nested] 3+ messages in thread

* Re: [edk2-devel] [PATCH v2] ArmPkg/ArmScmiDxe: Fix the calculation of RequiredArraySize in ClockDescribeRates()
  2023-02-03 14:23 [PATCH v2] ArmPkg/ArmScmiDxe: Fix the calculation of RequiredArraySize in ClockDescribeRates() Sudeep Holla
@ 2023-02-03 14:53 ` Sami Mujawar
  2023-02-06 13:57   ` Ard Biesheuvel
  0 siblings, 1 reply; 3+ messages in thread
From: Sami Mujawar @ 2023-02-03 14:53 UTC (permalink / raw)
  To: Sudeep Holla, devel

[-- Attachment #1: Type: text/plain, Size: 176 bytes --]

Hi Sudeep,

Thank you for the updated patch.

Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
Tested-by: Sami Mujawar <sami.mujawar@arm.com>

Regards,

Sami Mujawar

[-- Attachment #2: Type: text/html, Size: 224 bytes --]

^ permalink raw reply	[flat|nested] 3+ messages in thread

* Re: [edk2-devel] [PATCH v2] ArmPkg/ArmScmiDxe: Fix the calculation of RequiredArraySize in ClockDescribeRates()
  2023-02-03 14:53 ` [edk2-devel] " Sami Mujawar
@ 2023-02-06 13:57   ` Ard Biesheuvel
  0 siblings, 0 replies; 3+ messages in thread
From: Ard Biesheuvel @ 2023-02-06 13:57 UTC (permalink / raw)
  To: devel, sami.mujawar; +Cc: Sudeep Holla

On Fri, 3 Feb 2023 at 15:53, Sami Mujawar <sami.mujawar@arm.com> wrote:
>
> Hi Sudeep,
>
> Thank you for the updated patch.
>
> Reviewed-by: Sami Mujawar <sami.mujawar@arm.com>
> Tested-by: Sami Mujawar <sami.mujawar@arm.com>
>

Merged as #4006

Thanks all,

^ permalink raw reply	[flat|nested] 3+ messages in thread

end of thread, other threads:[~2023-02-06 13:57 UTC | newest]

Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2023-02-03 14:23 [PATCH v2] ArmPkg/ArmScmiDxe: Fix the calculation of RequiredArraySize in ClockDescribeRates() Sudeep Holla
2023-02-03 14:53 ` [edk2-devel] " Sami Mujawar
2023-02-06 13:57   ` Ard Biesheuvel

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox