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Message-ID: <30d972b1-9685-408b-a87c-98352c4a2449@quicinc.com>
Date: Tue, 30 Jan 2024 09:52:03 -0800
From: Unnathi Chalicheemala <quic_uchalich@...cinc.com>
To: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
CC: Bjorn Andersson <andersson@...nel.org>,
Konrad Dybcio
<konrad.dybcio@...aro.org>,
Rob Herring <robh+dt@...nel.org>,
"Krzysztof
Kozlowski" <krzysztof.kozlowski+dt@...aro.org>,
Conor Dooley
<conor+dt@...nel.org>, <linux-arm-msm@...r.kernel.org>,
<devicetree@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
<kernel@...cinc.com>
Subject: Re: [PATCH 5/5] soc: qcom: llcc: Add regmap for Broadcast_AND region
On 1/29/2024 2:03 PM, Dmitry Baryshkov wrote:
> On Mon, 29 Jan 2024 at 20:17, Unnathi Chalicheemala
> <quic_uchalich@...cinc.com> wrote:
>>
>>
>>
>> On 1/26/2024 12:29 PM, Dmitry Baryshkov wrote:
>>> On Fri, 26 Jan 2024 at 21:48, Unnathi Chalicheemala
>>> <quic_uchalich@...cinc.com> wrote:
>>>>
>>>> To support CSR programming, a broadcast interface is used to program
>>>> all channels in a single command. Until SM8450 there was only one
>>>> broadcast region (Broadcast_OR) used to broadcast write and check
>>>> for status bit 0. From SM8450 onwards another broadcast region
>>>> (Broadcast_AND) has been added which checks for status bit 1.
>>>>
>>>> Update llcc_drv_data structure with new regmap for Broadcast_AND
>>>> region and initialize regmap for Broadcast_AND region when HW block
>>>> version is greater than 4.1 for backwards compatibility.
>>>>
>>>> Switch from broadcast_OR to broadcast_AND region for checking
>>>> status bit 1 as Broadcast_OR region checks only for bit 0.
>>>
>>> This breaks backwards compatibility with the existing DT files, doesn't it?
>>>
>>
>> It shouldn't as checking for status bit 1 is happening only when the block
>> version is greater than 4.1, which is when Broadcast_AND region support
>> is added.
>
> Let me reiterate, please: with the existing DT files. You are patching
> DT files in patches 2-4, but this is not enough. DT files are
> considered to be ABI. As such old DT files must continue to work with
> newer kernels.
>
I'm sorry, I think I'm not understanding this right.
>>
>>>> While at it, also check return value after reading Broadcast_OR
>>>> region in llcc_update_act_ctrl().
>>>
>>> Separate patch, Fixes tag.
>>>
>>
>> Ack. Will remove this from existing patch.
>> Thanks for the review Dmitry!
>>
>>>>
>>>> Signed-off-by: Unnathi Chalicheemala <quic_uchalich@...cinc.com>
>>>> ---
>>>> drivers/soc/qcom/llcc-qcom.c | 12 +++++++++++-
>>>> include/linux/soc/qcom/llcc-qcom.h | 4 +++-
>>>> 2 files changed, 14 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/soc/qcom/llcc-qcom.c b/drivers/soc/qcom/llcc-qcom.c
>>>> index 4ca88eaebf06..5a2dac2d4772 100644
>>>> --- a/drivers/soc/qcom/llcc-qcom.c
>>>> +++ b/drivers/soc/qcom/llcc-qcom.c
>>>> @@ -849,7 +849,7 @@ static int llcc_update_act_ctrl(u32 sid,
>>>> return ret;
>>>>
>>>> if (drv_data->version >= LLCC_VERSION_4_1_0_0) {
>>>> - ret = regmap_read_poll_timeout(drv_data->bcast_regmap, status_reg,
>>>> + ret = regmap_read_poll_timeout(drv_data->bcast_and_regmap, status_reg,
>>>> slice_status, (slice_status & ACT_COMPLETE),
>>>> 0, LLCC_STATUS_READ_DELAY);
Above if condition will be true only for SM8450, 8550 and 8650 - whose DT files have been changed.
It would never check for other existing DT files - I guess I'm failing to understand why the code
would break with other DeviceTree files.
>>>> if (ret)
>>>> @@ -859,6 +859,8 @@ static int llcc_update_act_ctrl(u32 sid,
>>>> ret = regmap_read_poll_timeout(drv_data->bcast_regmap, status_reg,
>>>> slice_status, !(slice_status & status),
>>>> 0, LLCC_STATUS_READ_DELAY);
>>>> + if (ret)
>>>> + return ret;
>>>>
>>>> if (drv_data->version >= LLCC_VERSION_4_1_0_0)
>>>> ret = regmap_write(drv_data->bcast_regmap, act_clear_reg,
>>>> @@ -1282,6 +1284,14 @@ static int qcom_llcc_probe(struct platform_device *pdev)
>>>>
>>>> drv_data->version = version;
>>>>
>>>> + if (drv_data->version >= LLCC_VERSION_4_1_0_0) {
>>>> + drv_data->bcast_and_regmap = qcom_llcc_init_mmio(pdev, i + 1, "llcc_broadcast_and_base");
>>>> + if (IS_ERR(drv_data->bcast_and_regmap)) {
>>>> + ret = PTR_ERR(drv_data->bcast_and_regmap);
>>>> + goto err;
>>>> + }
>>>> + }
I have added a similar check in the probe function above; are you saying this too will break with
existing DT files?
>>>> +
>>>> llcc_cfg = cfg->sct_data;
>>>> sz = cfg->size;
>>>>
>>>> diff --git a/include/linux/soc/qcom/llcc-qcom.h b/include/linux/soc/qcom/llcc-qcom.h
>>>> index 1a886666bbb6..9e9f528b1370 100644
>>>> --- a/include/linux/soc/qcom/llcc-qcom.h
>>>> +++ b/include/linux/soc/qcom/llcc-qcom.h
>>>> @@ -115,7 +115,8 @@ struct llcc_edac_reg_offset {
>>>> /**
>>>> * struct llcc_drv_data - Data associated with the llcc driver
>>>> * @regmaps: regmaps associated with the llcc device
>>>> - * @bcast_regmap: regmap associated with llcc broadcast offset
>>>> + * @bcast_regmap: regmap associated with llcc broadcast OR offset
>>>> + * @bcast_and_regmap: regmap associated with llcc broadcast AND offset
>>>> * @cfg: pointer to the data structure for slice configuration
>>>> * @edac_reg_offset: Offset of the LLCC EDAC registers
>>>> * @lock: mutex associated with each slice
>>>> @@ -129,6 +130,7 @@ struct llcc_edac_reg_offset {
>>>> struct llcc_drv_data {
>>>> struct regmap **regmaps;
>>>> struct regmap *bcast_regmap;
>>>> + struct regmap *bcast_and_regmap;
>>>> const struct llcc_slice_config *cfg;
>>>> const struct llcc_edac_reg_offset *edac_reg_offset;
>>>> struct mutex lock;
>>>> --
>>>> 2.25.1
>>>>
>>>>
>>>
>>>
>
>
>
--
Thanks & Warm Regards,
Unnathi
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