[PATCH V2 1/1] dmaengine/amba-pl08x: Add support for s3c64xx DMAC
Linus Walleij
linus.walleij at linaro.org
Wed Sep 28 04:01:16 EDT 2011
Sorry if I missed a few nitpicks last time, anyway it's looking much better now:
On Wed, Sep 28, 2011 at 7:50 AM, Alim Akhtar <alim.akhtar at samsung.com> wrote:
> + /*
> + * Samsung pl080 DMAC has one exrta control register
s/exrta/exstra
> + if (pl08x->vd->is_pl080_s3c) {
> + writel(txd->ccfg, phychan->base + PL080S_CH_CONFIG);
> + writel(lli->cctl1, phychan->base + PL080S_CH_CONTROL2);
> + } else
> + writel(txd->ccfg, phychan->base + PL080_CH_CONFIG);
What do you think about adding a field to the struct pl08x
like
u32 config_reg
that we set to the proper config register (PL080S_CH_CONFIG or
PL080_CH_CONFIG in probe(), so the above
becomes the simpler variant:
writel(txd->ccfg, phychan->base + pl08x->config_reg);
if (pl08x->vd->is_pl080_s3c)
writel(lli->cctl1, phychan->base + PL080S_CH_CONTROL2);
> + if (pl08x->vd->is_pl080_s3c) {
> + val = readl(phychan->base + PL080S_CH_CONFIG);
> + while ((val & PL080_CONFIG_ACTIVE) ||
> + (val & PL080_CONFIG_ENABLE))
> + val = readl(phychan->base + PL080S_CH_CONFIG);
> +
> + writel(val | PL080_CONFIG_ENABLE,
> + phychan->base + PL080S_CH_CONFIG);
> + } else {
> val = readl(phychan->base + PL080_CH_CONFIG);
> + while ((val & PL080_CONFIG_ACTIVE) ||
> + (val & PL080_CONFIG_ENABLE))
> + val = readl(phychan->base + PL080_CH_CONFIG);
>
> - writel(val | PL080_CONFIG_ENABLE, phychan->base + PL080_CH_CONFIG);
> + writel(val | PL080_CONFIG_ENABLE,
> + phychan->base + PL080_CH_CONFIG);
> + }
This would also become much simpler with that approach I think...
> /* Set the HALT bit and wait for the FIFO to drain */
> - val = readl(ch->base + PL080_CH_CONFIG);
> - val |= PL080_CONFIG_HALT;
> - writel(val, ch->base + PL080_CH_CONFIG);
> -
> + if (pl08x->vd->is_pl080_s3c) {
> + val = readl(ch->base + PL080S_CH_CONFIG);
> + val |= PL080_CONFIG_HALT;
> + writel(val, ch->base + PL080S_CH_CONFIG);
> + } else {
> + val = readl(ch->base + PL080_CH_CONFIG);
> + val |= PL080_CONFIG_HALT;
> + writel(val, ch->base + PL080_CH_CONFIG);
> + }
This would become simply:
val = readl(ch->base + pl08x->config_reg);
val |= PL080_CONFIG_HALT;
writel(val, ch->base + pl08x->config_reg);
> /* Clear the HALT bit */
> - val = readl(ch->base + PL080_CH_CONFIG);
> - val &= ~PL080_CONFIG_HALT;
> - writel(val, ch->base + PL080_CH_CONFIG);
> + if (pl08x->vd->is_pl080_s3c) {
> + val = readl(ch->base + PL080S_CH_CONFIG);
> + val &= ~PL080_CONFIG_HALT;
> + writel(val, ch->base + PL080S_CH_CONFIG);
> + } else {
> + val = readl(ch->base + PL080_CH_CONFIG);
> + val &= ~PL080_CONFIG_HALT;
> + writel(val, ch->base + PL080_CH_CONFIG);
> + }
This would get rid of the if/else clauses
> + if (pl08x->vd->is_pl080_s3c) {
> + u32 val = readl(ch->base + PL080S_CH_CONFIG);
> + val &= ~(PL080_CONFIG_ENABLE | PL080_CONFIG_ERR_IRQ_MASK |
> + PL080_CONFIG_TC_IRQ_MASK);
> + writel(val, ch->base + PL080S_CH_CONFIG);
> + } else {
> + u32 val = readl(ch->base + PL080_CH_CONFIG);
> + val &= ~(PL080_CONFIG_ENABLE | PL080_CONFIG_ERR_IRQ_MASK |
> + PL080_CONFIG_TC_IRQ_MASK);
> + writel(val, ch->base + PL080_CH_CONFIG);
> + }
As would this...
> + /* Samsung DMAC is PL080 variant*/
> + {
> + .id = 0x00041082,
> + .mask = 0x000fffff,
> + .data = &vendor_pl080_s3c,
Does the hardware realy have this primecell number or is it something that is
hardcoded from the board/device tree?
If it is hardcoded then no objections.
In the latter case, replace 0x41 (= 'A', ARM) with something like
0x55 'U' for Samsung or so. Or 0x51 'S'. Or whatever you like.
Then add that to include/linux/amba/bus.h as
AMBA_VENDOR_SAMSUNG = 0x55,
so we have this under some kind of control.
Yours,
Linus Walleij
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