[PATCH] clk: qcom: mmcc-msm8974: remove ocmemcx_ahb_clk

[PATCH] clk: qcom: mmcc-msm8974: remove ocmemcx_ahb_clk

[Luca Weiss]

According to a commit in the 3.4 vendor kernel sources[0] the
ocmemcx_ahb_clk clock "is controlled by RPM and should not be touched by
APPS.".

[0] https://git.codelinaro.org/clo/la/kernel/msm/-/commit/37df5f2d91b4d5768b37fcaacaeea958dd683ebc

And indeed, when using MDSS+GPU+OCMEM on MSM8226 and not using
clk_ignore_unused, when Linux tries to disable the clock the device
crashes and reboots.

And since there's also no evidence of this clock in msm8974 vendor
kernel sources, remove the clock for msm8226 and msm8974.

Fixes: d8b212014e69 ("clk: qcom: Add support for MSM8974's multimedia clock controller (MMCC)")
Signed-off-by: Luca Weiss <luca@z3ntu.xyz>
---
 drivers/clk/qcom/mmcc-msm8974.c               | 18 ------------------
 include/dt-bindings/clock/qcom,mmcc-msm8974.h |  1 -
 2 files changed, 19 deletions(-)

diff --git a/drivers/clk/qcom/mmcc-msm8974.c b/drivers/clk/qcom/mmcc-msm8974.c
index c37524d55d8e..3ce40c80666b 100644
--- a/drivers/clk/qcom/mmcc-msm8974.c
+++ b/drivers/clk/qcom/mmcc-msm8974.c
@@ -2171,22 +2171,6 @@ static struct clk_branch mmss_s0_axi_clk = {
 	},
 };
 
-static struct clk_branch ocmemcx_ahb_clk = {
-	.halt_reg = 0x405c,
-	.clkr = {
-		.enable_reg = 0x405c,
-		.enable_mask = BIT(0),
-		.hw.init = &(struct clk_init_data){
-			.name = "ocmemcx_ahb_clk",
-			.parent_hws = (const struct clk_hw*[]){
-				&mmss_ahb_clk_src.clkr.hw
-			},
-			.num_parents = 1,
-			.ops = &clk_branch2_ops,
-		},
-	},
-};
-
 static struct clk_branch ocmemcx_ocmemnoc_clk = {
 	.halt_reg = 0x4058,
 	.clkr = {
@@ -2504,7 +2488,6 @@ static struct clk_regmap *mmcc_msm8226_clocks[] = {
 	[MMSS_MMSSNOC_BTO_AHB_CLK] = &mmss_mmssnoc_bto_ahb_clk.clkr,
 	[MMSS_MMSSNOC_AXI_CLK] = &mmss_mmssnoc_axi_clk.clkr,
 	[MMSS_S0_AXI_CLK] = &mmss_s0_axi_clk.clkr,
-	[OCMEMCX_AHB_CLK] = &ocmemcx_ahb_clk.clkr,
 	[OXILI_GFX3D_CLK] = &oxili_gfx3d_clk.clkr,
 	[OXILICX_AHB_CLK] = &oxilicx_ahb_clk.clkr,
 	[OXILICX_AXI_CLK] = &oxilicx_axi_clk.clkr,
@@ -2661,7 +2644,6 @@ static struct clk_regmap *mmcc_msm8974_clocks[] = {
 	[MMSS_MMSSNOC_BTO_AHB_CLK] = &mmss_mmssnoc_bto_ahb_clk.clkr,
 	[MMSS_MMSSNOC_AXI_CLK] = &mmss_mmssnoc_axi_clk.clkr,
 	[MMSS_S0_AXI_CLK] = &mmss_s0_axi_clk.clkr,
-	[OCMEMCX_AHB_CLK] = &ocmemcx_ahb_clk.clkr,
 	[OCMEMCX_OCMEMNOC_CLK] = &ocmemcx_ocmemnoc_clk.clkr,
 	[OCMEMNOC_CLK] = &ocmemnoc_clk.clkr,
 	[OXILI_GFX3D_CLK] = &oxili_gfx3d_clk.clkr,
diff --git a/include/dt-bindings/clock/qcom,mmcc-msm8974.h b/include/dt-bindings/clock/qcom,mmcc-msm8974.h
index a62cb0629a7a..743ee60632eb 100644
--- a/include/dt-bindings/clock/qcom,mmcc-msm8974.h
+++ b/include/dt-bindings/clock/qcom,mmcc-msm8974.h
@@ -121,7 +121,6 @@
 #define MMSS_MMSSNOC_BTO_AHB_CLK			112
 #define MMSS_MMSSNOC_AXI_CLK				113
 #define MMSS_S0_AXI_CLK					114
-#define OCMEMCX_AHB_CLK					115
 #define OCMEMCX_OCMEMNOC_CLK				116
 #define OXILI_OCMEMGX_CLK				117
 #define OCMEMNOC_CLK					118

---
base-commit: 7c2878be573282a9961c359b806ccf70afe1a6b6
change-id: 20230902-msm8226-ocmemcx_ahb_clk-remove-85dc043ccf12

Best regards,
-- 
Luca Weiss <luca@z3ntu.xyz>

Re: [PATCH] clk: qcom: mmcc-msm8974: remove ocmemcx_ahb_clk

[Konrad Dybcio]

On 2.09.2023 19:34, Luca Weiss wrote:
> According to a commit in the 3.4 vendor kernel sources[0] the
> ocmemcx_ahb_clk clock "is controlled by RPM and should not be touched by
> APPS.".
> 
> [0] https://git.codelinaro.org/clo/la/kernel/msm/-/commit/37df5f2d91b4d5768b37fcaacaeea958dd683ebc
> 
> And indeed, when using MDSS+GPU+OCMEM on MSM8226 and not using
> clk_ignore_unused, when Linux tries to disable the clock the device
> crashes and reboots.
> 
> And since there's also no evidence of this clock in msm8974 vendor
> kernel sources, remove the clock for msm8226 and msm8974.
Going over the downstream clock driver for 26 and 74 and comparing
the registered clocks with mainline may be useful.

Older clock drivers were likely written by hand and people doing
that likely didn't have a great reference of which clocks should
be skipped due to having been moved to firmware somewhere in the
bringup process.

Reviewed-by: Konrad Dybcio <konrad.dybcio@linaro.org>

Konrad

Re: [PATCH] clk: qcom: mmcc-msm8974: remove ocmemcx_ahb_clk

[Bjorn Andersson]

On Sat, 02 Sep 2023 19:34:23 +0200, Luca Weiss wrote:
> According to a commit in the 3.4 vendor kernel sources[0] the
> ocmemcx_ahb_clk clock "is controlled by RPM and should not be touched by
> APPS.".
> 
> [0] https://git.codelinaro.org/clo/la/kernel/msm/-/commit/37df5f2d91b4d5768b37fcaacaeea958dd683ebc
> 
> And indeed, when using MDSS+GPU+OCMEM on MSM8226 and not using
> clk_ignore_unused, when Linux tries to disable the clock the device
> crashes and reboots.
> 
> [...]

Applied, thanks!

[1/1] clk: qcom: mmcc-msm8974: remove ocmemcx_ahb_clk
      commit: 471e2875f8904539985e62220afd6c88e70779fa

Best regards,
-- 
Bjorn Andersson <andersson@kernel.org>