From: Elliot Berman <eberman@codeaurora.org>
To: Stephen Boyd <swboyd@chromium.org>,
Andy Gross <agross@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Brian Masney <masneyb@onstation.org>,
Stephan Gerhold <stephan@gerhold.net>,
Jeffrey Hugo <jhugo@codeaurora.org>,
Douglas Anderson <dianders@chromium.org>
Subject: Re: [PATCH 6/6] firmware: qcom_scm: Only compile legacy calls on ARM
Date: Fri, 5 Mar 2021 10:18:09 -0800 [thread overview]
Message-ID: <5ac262bf-a70a-4ca3-01a8-d1432732d26f@codeaurora.org> (raw)
In-Reply-To: <161483844056.1478170.8701629037531614722@swboyd.mtv.corp.google.com>
On 3/3/2021 10:14 PM, Stephen Boyd wrote:
> Quoting Elliot Berman (2021-03-03 19:35:08)
>>
>> On 2/23/2021 1:45 PM, Stephen Boyd wrote:
>>> These scm calls are never used outside of legacy ARMv7 based platforms.
>>> That's because PSCI, mandated on arm64, implements them for modern SoCs
>>> via the PSCI spec. Let's move them to the legacy file and only compile
>>> the legacy file into the kernel when CONFIG_ARM=y. Otherwise provide
>>> stubs and fail the calls. This saves a little bit of space in an
>>> arm64 allmodconfig >
>>> $ ./scripts/bloat-o-meter vmlinux.before vmlinux.after
>>> add/remove: 0/8 grow/shrink: 5/7 up/down: 509/-4405 (-3896)
>>> Function old new delta
>>> __qcom_scm_set_dload_mode.constprop 312 452 +140
>>> qcom_scm_qsmmu500_wait_safe_toggle 288 416 +128
>>> qcom_scm_io_writel 288 408 +120
>>> qcom_scm_io_readl 376 492 +116
>>> __param_str_download_mode 23 28 +5
>>> __warned 4327 4326 -1
>>> qcom_iommu_init 272 268 -4
>>> e843419@0b3f_00010432_324 8 - -8
>>> qcom_scm_call 228 208 -20
>>> CSWTCH 5925 5877 -48
>>> _sub_I_65535_1 163100 163040 -60
>>> _sub_D_65535_0 163100 163040 -60
>>> qcom_scm_wb 64 - -64
>>> qcom_scm_lock 320 160 -160
>>> qcom_scm_call_atomic 212 - -212
>>> qcom_scm_cpu_power_down 308 - -308
>>> scm_legacy_call_atomic 520 - -520
>>> qcom_scm_set_warm_boot_addr 720 - -720
>>> qcom_scm_set_cold_boot_addr 728 - -728
>>> scm_legacy_call 1492 - -1492
>>> Total: Before=66737642, After=66733746, chg -0.01%
>>>
>>> Commit 9a434cee773a ("firmware: qcom_scm: Dynamically support SMCCC and
>>> legacy conventions") didn't mention any motivating factors for keeping
>>> the legacy code around on arm64 kernels, i.e. presumably that commit
>>> wasn't trying to support these legacy APIs on arm64 kernels.
>>
>> There are arm targets which support SMCCC convention and use some of
>> these removed functions. Can these functions be kept in qcom-scm.c and
>> wrapped with #if IS_ENABLED(CONFIG_ARM)?
>>
>
> It can be wrapped in qcom-scm.c, but why? It's all the same object file
> so I'm lost why it matters. I suppose it would make it so the struct
> doesn't have to be moved around and declared in the header? Any other
> reason? I moved it to the legacy file so that it was very obvious that
> the API wasn't to be used except for "legacy" platforms that don't use
> PSCI.
>
There are "legacy" arm platforms that use the SMCCC (scm_smc_call) and
use the qcom_scm_set_{warm,cold}_boot_addr and qcom_scm_cpu_power_down
functions.
> + desc.args[0] = flags;
> + desc.args[1] = virt_to_phys(entry);
> +
> + return scm_legacy_call_atomic(NULL, &desc, NULL);
> +}
> +EXPORT_SYMBOL(qcom_scm_set_cold_boot_addr);
This should still be qcom_scm_call.
next prev parent reply other threads:[~2021-03-05 18:19 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-23 21:45 [PATCH 0/6] firmware: qcom_scm: Fix SMCCC detection on sc7180 Stephen Boyd
2021-02-23 21:45 ` [PATCH 1/6] firmware: qcom_scm: Make __qcom_scm_is_call_available() return bool Stephen Boyd
2021-03-06 0:44 ` Bjorn Andersson
2021-02-23 21:45 ` [PATCH 2/6] firmware: qcom_scm: Reduce locking section for __get_convention() Stephen Boyd
2021-02-23 21:45 ` [PATCH 3/6] firmware: qcom_scm: Workaround lack of "is available" call on SC7180 Stephen Boyd
2021-02-23 23:38 ` Jeffrey Hugo
2021-02-23 23:46 ` Stephen Boyd
2021-02-23 21:45 ` [PATCH 4/6] firmware: qcom_scm: Suppress sysfs bind attributes Stephen Boyd
2021-02-23 21:45 ` [PATCH 5/6] firmware: qcom_scm: Fix kernel-doc function names to match Stephen Boyd
2021-02-23 21:45 ` [PATCH 6/6] firmware: qcom_scm: Only compile legacy calls on ARM Stephen Boyd
2021-03-04 3:35 ` Elliot Berman
2021-03-04 6:14 ` Stephen Boyd
2021-03-05 18:18 ` Elliot Berman [this message]
2021-03-06 6:18 ` Stephen Boyd
2021-03-07 17:42 ` Bjorn Andersson
2021-03-23 3:36 ` Stephen Boyd
2021-03-23 18:27 ` Elliot Berman
2021-03-23 18:46 ` Bjorn Andersson
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5ac262bf-a70a-4ca3-01a8-d1432732d26f@codeaurora.org \
--to=eberman@codeaurora.org \
--cc=agross@kernel.org \
--cc=bjorn.andersson@linaro.org \
--cc=dianders@chromium.org \
--cc=jhugo@codeaurora.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=masneyb@onstation.org \
--cc=stephan@gerhold.net \
--cc=swboyd@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).