From: Chanwoo Choi <cw00.choi@samsung.com>
To: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
leonard.crestez@nxp.com, myungjoo.ham@samsung.com,
kyungmin.park@samsung.com
Subject: Re: [v8 PATCH] PM / devfreq: Add dynamic scaling for imx8m ddr controller
Date: Fri, 20 Dec 2019 08:10:21 +0900 [thread overview]
Message-ID: <6c00b0d8-af71-b211-d5bb-87c48e5d5db5@samsung.com> (raw)
In-Reply-To: <20191219230919.16037-1-cw00.choi@samsung.com>
On 12/20/19 8:09 AM, Chanwoo Choi wrote:
> From: Leonard Crestez <leonard.crestez@nxp.com>
>
> Add driver for dynamic scaling the DDR Controller on imx8m chips. Actual
> frequency switching is implemented inside TF-A, this driver wraps the
> SMC calls and synchronizes the clk tree.
>
> The DRAM clocks on imx8m have the following structure (abridged):
>
> +----------+ |\ +------+
> | dram_pll |-------|M| dram_core | |
> +----------+ |U|---------->| D |
> /--|X| | D |
> dram_alt_root | |/ | R |
> | | C |
> +---------+ | |
> |FIX DIV/4| | |
> +---------+ | |
> composite: | | |
> +----------+ | | |
> | dram_alt |----/ | |
> +----------+ | |
> | dram_apb |-------------------->| |
> +----------+ +------+
>
> The dram_pll is used for higher rates and dram_alt is used for lower
> rates. The dram_alt and dram_apb clocks are "imx composite" and their
> parent can also be modified.
>
> This driver will prepare/enable the new parents ahead of switching (so
> that the expected roots are enabled) and afterwards it will call
> clk_set_parent to ensure the parents in clock framework are up-to-date.
>
> The driver relies on dram_pll dram_alt and dram_apb being marked with
> CLK_GET_RATE_NOCACHE for rate updates.
>
> Signed-off-by: Leonard Crestez <leonard.crestez@nxp.com>
> Acked-by: Chanwoo Choi <cw00.choi@samsung.com>
> [cw00.choi: Edit the COMPILE_TEST module dependency in Kconfig]
> Signed-off-by: Chanwoo Choi <cw00.choi@samsung.com>
> ---
> Changes from v7:
> - Squash patch[1] to this patch
> [1] https://patchwork.kernel.org/patch/11303869/
> - [PATCH] PM / devfreq: imx8m-ddrc: Fix argument swap in error print
Applied it.
(snip)
--
Best Regards,
Chanwoo Choi
Samsung Electronics
prev parent reply other threads:[~2019-12-19 23:03 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <c0b332b85560e39d7dbb5e88b99bbed1d1b32373.1574458460.git.leonard.crestez@nxp.com>
[not found] ` <CGME20191219230258epcas1p16ec64c3a06eafd9f0a3784d18541ce5c@epcas1p1.samsung.com>
2019-12-19 23:09 ` [v8 PATCH] PM / devfreq: Add dynamic scaling for imx8m ddr controller Chanwoo Choi
2019-12-19 23:10 ` Chanwoo Choi [this message]
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=6c00b0d8-af71-b211-d5bb-87c48e5d5db5@samsung.com \
--to=cw00.choi@samsung.com \
--cc=devicetree@vger.kernel.org \
--cc=kyungmin.park@samsung.com \
--cc=leonard.crestez@nxp.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=myungjoo.ham@samsung.com \
/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).