On 11/24/2018 12:04 AM, Will Deacon wrote:
On Fri, Nov 23, 2018 at 03:06:29PM +0530, Vivek Gautam wrote:
On Fri, Nov 23, 2018 at 2:52 PM Tomasz Figa <tfiga@xxxxxxxxxxxx> wrote:
On Fri, Nov 23, 2018 at 6:13 PM Vivek Gautam
<vivek.gautam@xxxxxxxxxxxxxx> wrote:
On Wed, Nov 21, 2018 at 11:09 PM Will Deacon <will.deacon@xxxxxxx> wrote:
On Fri, Nov 16, 2018 at 04:54:30PM +0530, Vivek Gautam wrote:
@@ -2026,6 +2027,17 @@ ARM_SMMU_MATCH_DATA(arm_mmu401, ARM_SMMU_V1_64K, GENERIC_SMMU);
ARM_SMMU_MATCH_DATA(arm_mmu500, ARM_SMMU_V2, ARM_MMU500);
ARM_SMMU_MATCH_DATA(cavium_smmuv2, ARM_SMMU_V2, CAVIUM_SMMUV2);
+static const char * const qcom_smmuv2_clks[] = {
+ "bus", "iface",
+};
+
+static const struct arm_smmu_match_data qcom_smmuv2 = {
+ .version = ARM_SMMU_V2,
+ .model = QCOM_SMMUV2,
+ .clks = qcom_smmuv2_clks,
+ .num_clks = ARRAY_SIZE(qcom_smmuv2_clks),
+};
These seems redundant if we go down the route proposed by Thor, where we
just pull all of the clocks out of the device-tree. In which case, why
do we need this match_data at all?
Which is better? Driver relying solely on the device tree to tell
which all clocks
are required to be enabled,
or, the driver deciding itself based on the platform's match data,
that it should
have X, Y, & Z clocks that should be supplied from the device tree.
The former would simplify the driver, but would also make it
impossible to spot mistakes in DT, which would ultimately surface out
as very hard to debug bugs (likely complete system lockups).
Thanks.
Yea, this is how I understand things presently. Relying on device tree
puts the things out of driver's control.
But it also has the undesirable effect of having to update the driver
code whenever we want to add support for a new SMMU implementation. If
we do this all in the DT, as Thor is trying to do, then older kernels
will work well with new hardware.
Hi Will,
Am I unable to understand the intentions here for Thor's clock-fetch
design change?
I'm having trouble parsing your question, sorry. Please work with Thor
so that we have a single way to get the clock information. My preference
is to take it from the firmware, for the reason I stated above.
Hi Will,
Sure, thanks. I will work with Thor to get this going.
Hi Thor,
Does it sound okay to you to squash your patch [1] into my patch [2] with
your 'Signed-off-by' tag?
I will update the commit log to include the information about getting
clock details from device tree.
[1] https://patchwork.kernel.org/patch/10628725/
[2] https://patchwork.kernel.org/patch/10686061/
Best regards
Vivek
Will
