Linux-ARM-MSM Archive on lore.kernel.org
 help / color / Atom feed
From: Vinod Koul <vkoul@kernel.org>
To: Bjorn Andersson <bjorn.andersson@linaro.org>
Cc: Stephen Boyd <sboyd@kernel.org>,
	linux-arm-msm@vger.kernel.org, Andy Gross <agross@kernel.org>,
	David Brown <david.brown@linaro.org>,
	Michael Turquette <mturquette@baylibre.com>,
	linux-clk@vger.kernel.org
Subject: Re: [PATCH v2 1/5] clk: qcom: clk-alpha-pll: Remove unnecessary cast
Date: Mon, 24 Jun 2019 13:16:57 +0530
Message-ID: <20190624074657.GX2962@vkoul-mobl> (raw)
In-Reply-To: <20190617043734.GH750@tuxbook-pro>

On 16-06-19, 21:37, Bjorn Andersson wrote:
> On Wed 12 Jun 02:17 PDT 2019, Vinod Koul wrote:
> 
> > We have couple of instances in the driver with unnecessary
> > u64 casts, drop them.
> > 
> > Signed-off-by: Vinod Koul <vkoul@kernel.org>
> > ---
> >  drivers/clk/qcom/clk-alpha-pll.c | 4 ++--
> >  1 file changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/clk/qcom/clk-alpha-pll.c b/drivers/clk/qcom/clk-alpha-pll.c
> > index 0ced4a5a9a17..b48707693ffd 100644
> > --- a/drivers/clk/qcom/clk-alpha-pll.c
> > +++ b/drivers/clk/qcom/clk-alpha-pll.c
> > @@ -832,7 +832,7 @@ static int clk_alpha_pll_postdiv_set_rate(struct clk_hw *hw, unsigned long rate,
> >  	int div;
> >  
> >  	/* 16 -> 0xf, 8 -> 0x7, 4 -> 0x3, 2 -> 0x1, 1 -> 0x0 */
> > -	div = DIV_ROUND_UP_ULL((u64)parent_rate, rate) - 1;
> > +	div = DIV_ROUND_UP_ULL(parent_rate, rate) - 1;
> 
> Afaict DIV_ROUND_UP_ULL() will first add "parent_rate" and "rate" and
> then stash this in a unsigned long long and do the division. So what
> happens if parent_rate + rate > 32 bits on a 32-bit target?
> 
> (Shouldn't there be a cast of (ll) in the macro to ULL?)

Agreed, though DIV_ROUND_DOWN_ULL does it correctly, right fix would be to make it:

#define DIV_ROUND_UP_ULL(ll, d)         DIV_ROUND_DOWN_ULL(unsigned long long(ll) + (d) - 1, (d)) 

I will post that as well..

Thanks

-- 
~Vinod

  reply index

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-12  9:17 [PATCH v2 0/5] clk: qcom: Add support for SM8150 GCC Vinod Koul
2019-06-12  9:17 ` [PATCH v2 1/5] clk: qcom: clk-alpha-pll: Remove unnecessary cast Vinod Koul
2019-06-17  4:37   ` Bjorn Andersson
2019-06-24  7:46     ` Vinod Koul [this message]
2019-06-12  9:17 ` [PATCH v2 2/5] clk: qcom: clk-alpha-pll: Remove post_div_table checks Vinod Koul
2019-06-17  4:28   ` Bjorn Andersson
2019-06-12  9:17 ` [PATCH v2 3/5] clk: qcom: gcc-qcs404: Add MODULE_ALIAS Vinod Koul
2019-06-17  4:26   ` Bjorn Andersson
2019-06-24  7:55     ` Vinod Koul
2019-06-12  9:17 ` [PATCH v2 4/5] clk: qcom: clk-alpha-pll: Add support for Trion PLLs Vinod Koul
2019-06-13  3:04   ` Taniya Das
2019-06-14  5:42     ` Vinod Koul
2019-06-17  6:10       ` Taniya Das
2019-06-17  6:16         ` Vinod Koul

Reply instructions:

You may reply publically 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=20190624074657.GX2962@vkoul-mobl \
    --to=vkoul@kernel.org \
    --cc=agross@kernel.org \
    --cc=bjorn.andersson@linaro.org \
    --cc=david.brown@linaro.org \
    --cc=linux-arm-msm@vger.kernel.org \
    --cc=linux-clk@vger.kernel.org \
    --cc=mturquette@baylibre.com \
    --cc=sboyd@kernel.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

Linux-ARM-MSM Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-arm-msm/0 linux-arm-msm/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-arm-msm linux-arm-msm/ https://lore.kernel.org/linux-arm-msm \
		linux-arm-msm@vger.kernel.org linux-arm-msm@archiver.kernel.org
	public-inbox-index linux-arm-msm


Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.kernel.vger.linux-arm-msm


AGPL code for this site: git clone https://public-inbox.org/ public-inbox