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Date:   Thu, 14 Nov 2019 09:34:42 -0800
From:   Matthias Kaehlcke <mka@chromium.org>
To:     Taniya Das <tdas@codeaurora.org>
Cc:     Stephen Boyd <sboyd@kernel.org>,
        Michael Turquette =?utf-8?B?wqA=?= <mturquette@baylibre.com>,
        David Brown <david.brown@linaro.org>,
        Rajendra Nayak <rnayak@codeaurora.org>,
        linux-arm-msm@vger.kernel.org, linux-soc@vger.kernel.org,
        linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
        devicetree@vger.kernel.org, robh@kernel.org, robh+dt@kernel.org
Subject: Re: [PATCH v4 5/5] clk: qcom: Add Global Clock controller (GCC)
 driver for SC7180
Message-ID: <20191114173442.GH27773@google.com>
References: <20191014102308.27441-1-tdas@codeaurora.org>
 <20191014102308.27441-6-tdas@codeaurora.org>
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On Mon, Oct 14, 2019 at 03:53:08PM +0530, Taniya Das wrote:
> Add support for the global clock controller found on SC7180
> based devices. This should allow most non-multimedia device
> drivers to probe and control their clocks.
> 
> Signed-off-by: Taniya Das <tdas@codeaurora.org>
> ---
>  drivers/clk/qcom/Kconfig      |    9 +
>  drivers/clk/qcom/Makefile     |    1 +
>  drivers/clk/qcom/gcc-sc7180.c | 2450 +++++++++++++++++++++++++++++++++
>  3 files changed, 2460 insertions(+)
>  create mode 100644 drivers/clk/qcom/gcc-sc7180.c
> 
> diff --git a/drivers/clk/qcom/Kconfig b/drivers/clk/qcom/Kconfig
> index 32dbb4f09492..91706d88eeeb 100644
> --- a/drivers/clk/qcom/Kconfig
> +++ b/drivers/clk/qcom/Kconfig
> @@ -227,6 +227,15 @@ config QCS_GCC_404
>  	  Say Y if you want to use multimedia devices or peripheral
>  	  devices such as UART, SPI, I2C, USB, SD/eMMC, PCIe etc.
> 
> +config SC_GCC_7180
> +	tristate "SC7180 Global Clock Controller"
> +	select QCOM_GDSC
> +	depends on COMMON_CLK_QCOM
> +	help
> +	  Support for the global clock controller on SC7180 devices.
> +	  Say Y if you want to use peripheral devices such as UART, SPI,
> +	  I2C, USB, UFS, SDCC, etc.
> +
>  config SDM_CAMCC_845
>  	tristate "SDM845 Camera Clock Controller"
>  	select SDM_GCC_845
> diff --git a/drivers/clk/qcom/Makefile b/drivers/clk/qcom/Makefile
> index 4a813b4055d0..6fb356a0bbf5 100644
> --- a/drivers/clk/qcom/Makefile
> +++ b/drivers/clk/qcom/Makefile
> @@ -43,6 +43,7 @@ obj-$(CONFIG_QCOM_CLK_RPMH) += clk-rpmh.o
>  obj-$(CONFIG_QCOM_CLK_SMD_RPM) += clk-smd-rpm.o
>  obj-$(CONFIG_QCS_GCC_404) += gcc-qcs404.o
>  obj-$(CONFIG_QCS_TURING_404) += turingcc-qcs404.o
> +obj-$(CONFIG_SC_GCC_7180) += gcc-sc7180.o
>  obj-$(CONFIG_SDM_CAMCC_845) += camcc-sdm845.o
>  obj-$(CONFIG_SDM_DISPCC_845) += dispcc-sdm845.o
>  obj-$(CONFIG_SDM_GCC_660) += gcc-sdm660.o
> diff --git a/drivers/clk/qcom/gcc-sc7180.c b/drivers/clk/qcom/gcc-sc7180.c
> new file mode 100644
> index 000000000000..38424e63bcae
> --- /dev/null
> +++ b/drivers/clk/qcom/gcc-sc7180.c
> ...
> +static int __init gcc_sc7180_init(void)
> +{
> +	return platform_driver_register(&gcc_sc7180_driver);
> +}
> +core_initcall(gcc_sc7180_init);

This was a subsys_initcall in v3. In combination with the MSS clock driver
for SC7180 (not posted yet) the change 'causes' an abort:

[    4.892250] DBG: clk_is_enabled_regmap: mss_axi_nav_clk

[    4.586124] Internal error: synchronous external abort: 96000010 [#1] PREEMPT SMP
[    4.593817] Modules linked in:
[    4.596976] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G S      W         5.4.0-rc6 #27
[    4.604843] Hardware name: Qualcomm Technologies, Inc. SC7180 IDP (DT)
[    4.611550] pstate: 20c00089 (nzCv daIf +PAN +UAO)
[    4.616484] pc : regmap_mmio_read32le+0x20/0x40
[    4.621140] lr : regmap_mmio_read+0x44/0x6c
[    4.625443] sp : ffffffc01005bb10
[    4.628863] x29: ffffffc01005bb20 x28: 0000000000000000
[    4.634331] x27: 0000000000000000 x26: 0000000000000000
[    4.639787] x25: 0000000000000000 x24: ffffffd9a8ae1018
[    4.645244] x23: ffffffd9a8e12148 x22: ffffff8177292800
[    4.650712] x21: 00000000000000bc x20: ffffff8177342d80
[    4.656168] x19: 00000000000000bc x18: 0000000059d6eecd
[    4.661635] x17: 00000000765f46d1 x16: 00000000bbaf844b
[    4.667103] x15: 0000000098366c8e x14: 4000000000000000
[    4.672559] x13: ffffff8174b43b30 x12: 0000000000000000
[    4.678015] x11: 0000000000000000 x10: 0000000000000000
[    4.683482] x9 : 0000000000000001 x8 : ffffffc0100250bc
[    4.688949] x7 : 0000000000000008 x6 : 0000000000000000
[    4.694416] x5 : 0000000000000000 x4 : 0000000000000000
[    4.699873] x3 : 0000000000000000 x2 : ffffffc01005bc04
[    4.705340] x1 : 00000000000000bc x0 : ffffff8177342d80
[    4.710807] Call trace:
[    4.713330]  regmap_mmio_read32le+0x20/0x40
[    4.717634]  regmap_mmio_read+0x44/0x6c
[    4.721591]  _regmap_bus_reg_read+0x34/0x44
[    4.725895]  _regmap_read+0x88/0x16c
[    4.729580]  regmap_read+0x54/0x78
[    4.733088]  clk_is_enabled_regmap+0x34/0x84
[    4.737478]  clk_core_is_enabled+0x68/0xac
[    4.741699]  clk_disable_unused_subtree+0x90/0x23c
[    4.746621]  clk_disable_unused+0x44/0x108
[    4.750844]  do_one_initcall+0x120/0x2bc
[    4.754886]  do_initcall_level+0x14c/0x174
[    4.759105]  do_basic_setup+0x30/0x48
[    4.762876]  kernel_init_freeable+0xc4/0x144
[    4.767266]  kernel_init+0x14/0x100
[    4.770855]  ret_from_fork+0x10/0x18
[    4.774546] Code: aa0003f4 d503201f f9400288 8b334108 (b9400100)
[    4.780813] ---[ end trace e75cb36fe5e38dd3 ]---
[    4.791327] Kernel panic - not syncing: Fatal exception
[    4.796710] SMP: stopping secondary CPUs
[    4.801330] Kernel Offset: 0x1997c00000 from 0xffffffc010000000
[    4.807414] PHYS_OFFSET: 0xfffffff180000000
[    4.811718] CPU features: 0x0006,2a80aa18
[    4.815841] Memory Limit: none
[    4.824753] ---[ end Kernel panic - not syncing: Fatal exception ]---

I understand that we don't care too much about the MSS clock driver at this
point since it is out of tree, just wanted to mention it, maybe it helps saving
a bit of time debugging later on.