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From: Matthias Kaehlcke <mka@chromium.org> To: Doug Anderson <dianders@chromium.org> Cc: Maulik Shah <mkshah@codeaurora.org>, Andy Gross <agross@kernel.org>, Bjorn Andersson <bjorn.andersson@linaro.org>, Rajendra Nayak <rnayak@codeaurora.org>, Evan Green <evgreen@chromium.org>, Stephen Boyd <swboyd@chromium.org>, Lina Iyer <ilina@codeaurora.org>, linux-arm-msm <linux-arm-msm@vger.kernel.org>, LKML <linux-kernel@vger.kernel.org> Subject: Re: [RFT PATCH 1/9] drivers: qcom: rpmh-rsc: Clean code reading/writing regs/cmds Date: Wed, 11 Mar 2020 09:17:26 -0700 [thread overview] Message-ID: <20200311161726.GA144492@google.com> (raw) In-Reply-To: <CAD=FV=X649r8qrNRZSezUBEuJbt0oZg6VBweAGjEhxOPp0zf2w@mail.gmail.com> Hi, On Wed, Mar 11, 2020 at 08:03:27AM -0700, Doug Anderson wrote: > Hi, > > On Wed, Mar 11, 2020 at 1:47 AM Maulik Shah <mkshah@codeaurora.org> wrote: > > > > Hi, > > > > On 3/7/2020 5:29 AM, Douglas Anderson wrote: > > > This patch makes two changes, both of which should be no-ops: > > > > > > 1. Make read_tcs_reg() / read_tcs_cmd() symmetric to write_tcs_reg() / > > > write_tcs_cmd(). > > > > i agree that there are two different write function doing same thing except last addition (RSC_DRV_CMD_OFFSET * cmd_id) > > > > can you please rename write_tcs_cmd() to write_tcs_reg(), add above operation in it, and then remove existing write_tcs_reg(). > > this way we have only one read and one write function. > > > > so at the end we will two function as, > > > > static u32 read_tcs_reg(struct rsc_drv *drv, int reg, int tcs_id, int cmd_id) > > { > > return readl_relaxed(drv->tcs_base + reg + RSC_DRV_TCS_OFFSET * tcs_id + > > RSC_DRV_CMD_OFFSET * cmd_id); > > } > > > > static void write_tcs_reg(struct rsc_drv *drv, int reg, int tcs_id, int cmd_id, > > u32 data) > > { > > writel_relaxed(data, drv->tcs_base + reg + RSC_DRV_TCS_OFFSET * tcs_id + > > RSC_DRV_CMD_OFFSET * cmd_id); > > } > > I can if you insist and this is still better than the existing > (inconsistent) code. > > ...but I still feel that having two functions adds value here. > > > Anyone else who is CCed want to weigh in and tie break? I agree with Doug, having two functions makes the code that calls them clearer. It makes it evident when a command is read/written and doesn't require a useless extra parameter when accessing a non-command register. > > > 2. Change the order of operations in the above functions to make it > > > more obvious to me what the math is doing. Specifically first you > > > want to find the right TCS, then the right register, and then > > > multiply by the command ID if necessary. > > With above change, i don't think you need to re-order this. > > specifically from tcs->base, we find right "reg" first and if it happens to be tcs then intended tcs, and then cmd inside tcs. > > There was never any "need" to re-order. That math works out to be the > same. This is just clearer. > > As an example, let's look at this: > > struct point { > int x; > int y; > }; > struct point points[10]; > > Let's say you have: > void *points_base = &(points[0]); > > ...and now you want to find &(points[5].y). What does your math look like? > > a) points_base + (sizeof(struct point) * 5) + 4 ; > > ...or... > > b) points_base + 4 + (sizeof(struct point) * 5); > > > Both calculations give the same result, but I am arguring that "a)" is > more intuitive. Specifically you deal with the array access first and > then deal with the offset within the structure that you found. +1
next prev parent reply other threads:[~2020-03-11 16:17 UTC|newest] Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-03-06 23:59 [RFT PATCH 0/9] drivers: qcom: rpmh-rsc: Cleanup / add lots of comments Douglas Anderson 2020-03-06 23:59 ` [RFT PATCH 1/9] drivers: qcom: rpmh-rsc: Clean code reading/writing regs/cmds Douglas Anderson 2020-03-11 8:47 ` Maulik Shah 2020-03-11 15:03 ` Doug Anderson 2020-03-11 16:17 ` Matthias Kaehlcke [this message] 2020-03-11 19:30 ` Stephen Boyd 2020-03-06 23:59 ` [RFT PATCH 2/9] drivers: qcom: rpmh-rsc: Document the register layout better Douglas Anderson 2020-03-11 9:35 ` Maulik Shah 2020-03-11 15:27 ` Doug Anderson 2020-03-11 18:49 ` Evan Green 2020-03-11 20:08 ` Stephen Boyd 2020-03-11 22:35 ` Doug Anderson 2020-03-06 23:59 ` [RFT PATCH 3/9] drivers: qcom: rpmh-rsc: Fold tcs_ctrl_write() into its single caller Douglas Anderson 2020-03-11 9:50 ` Maulik Shah 2020-03-06 23:59 ` [RFT PATCH 4/9] drivers: qcom: rpmh-rsc: Remove get_tcs_of_type() abstraction Douglas Anderson 2020-03-11 12:02 ` Maulik Shah 2020-03-06 23:59 ` [RFT PATCH 5/9] drivers: qcom: rpmh-rsc: A lot of comments Douglas Anderson 2020-03-06 23:59 ` [RFT PATCH 6/9] drivers: qcom: rpmh-rsc: Only use "tcs_in_use" for ACTIVE_ONLY Douglas Anderson 2020-03-11 0:33 ` Doug Anderson 2020-03-06 23:59 ` [RFT PATCH 7/9] drivers: qcom: rpmh-rsc: Warning if tcs_write() used for non-active Douglas Anderson 2020-03-06 23:59 ` [RFT PATCH 8/9] drivers: qcom: rpmh-rsc: spin_lock_irqsave() for tcs_invalidate() Douglas Anderson 2020-03-06 23:59 ` [RFT PATCH 9/9] drivers: qcom: rpmh-rsc: Kill cmd_cache and find_match() with fire Douglas Anderson 2020-03-11 0:35 ` Doug Anderson 2020-03-11 9:48 ` [RFT PATCH 0/9] drivers: qcom: rpmh-rsc: Cleanup / add lots of comments Maulik Shah
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