Messages in this thread | | | From | Doug Anderson <> | Date | Wed, 11 Mar 2020 08:03:27 -0700 | Subject | Re: [RFT PATCH 1/9] drivers: qcom: rpmh-rsc: Clean code reading/writing regs/cmds |
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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?
> > 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.
-Doug
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