Re: [PATCH v3 13/15] memory: mtk-smi: Get rid of need_larbid

Matthias Brugger
2018-12-02T23:04:43Z

On 17/11/2018 03:35, Yong Wu wrote:
> The "mediatek,larb-id" has already been parsed in MTK IOMMU driver.
> It's no need to parse it again in SMI driver. Only clean some codes.
> This patch is fit for all the current mt2701, mt2712, mt7623, mt8173
> and mt8183.

I'm trying to understand why we need the mediatek,larb-id at all. From what I
understand as long as the mediatek larbs described in the iommu are ordered
(larb0, larb1, larb2, etc) we actually get the same value as defined by
mediatek,larb-id. At least this holds for all present implementations.

On the other hand I don't see where the mtk_iommu_v1 driver actually parses the
larb-id, can you please help to understand:

1) why we need the larb-id at all
2) how this will work if we do not parse the larb-id for v1 iommu at all

Thanks a lot,
Matthias

>
> Signed-off-by: Yong Wu <yong.wu@mediatek.com>
> ---
> drivers/memory/mtk-smi.c | 27 ++-------------------------
> 1 file changed, 2 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/memory/mtk-smi.c b/drivers/memory/mtk-smi.c
> index e4daabb..e0265fe 100644
> --- a/drivers/memory/mtk-smi.c
> +++ b/drivers/memory/mtk-smi.c
> @@ -67,7 +67,6 @@ struct mtk_smi_common_plat {
> };
>
> struct mtk_smi_larb_gen {
> - bool need_larbid;
> int port_in_larb[MTK_LARB_NR_MAX + 1];
> void (*config_port)(struct device *);
> unsigned int larb_special_mask; /* The special larbs mask. */
> @@ -152,18 +151,9 @@ void mtk_smi_larb_put(struct device *larbdev)
> struct mtk_smi_iommu *smi_iommu = data;
> unsigned int i;
>
> - if (larb->larb_gen->need_larbid) {
> - larb->mmu = &smi_iommu->larb_imu[larb->larbid].mmu;
> - return 0;
> - }
> -
> - /*
> - * If there is no larbid property, Loop to find the corresponding
> - * iommu information.
> - */
> - for (i = 0; i < smi_iommu->larb_nr; i++) {
> + for (i = 0; i < MTK_LARB_NR_MAX; i++) {
> if (dev == smi_iommu->larb_imu[i].dev) {
> - /* The 'mmu' may be updated in iommu-attach/detach. */
> + larb->larbid = i;
> larb->mmu = &smi_iommu->larb_imu[i].mmu;
> return 0;
> }
> @@ -242,7 +232,6 @@ static void mtk_smi_larb_config_port_gen1(struct device *dev)
> };
>
> static const struct mtk_smi_larb_gen mtk_smi_larb_mt2701 = {
> - .need_larbid = true,
> .port_in_larb = {
> LARB0_PORT_OFFSET, LARB1_PORT_OFFSET,
> LARB2_PORT_OFFSET, LARB3_PORT_OFFSET
> @@ -251,13 +240,11 @@ static void mtk_smi_larb_config_port_gen1(struct device *dev)
> };
>
> static const struct mtk_smi_larb_gen mtk_smi_larb_mt2712 = {
> - .need_larbid = true,
> .config_port = mtk_smi_larb_config_port_gen2_general,
> .larb_special_mask = BIT(8) | BIT(9), /* bdpsys */
> };
>
> static const struct mtk_smi_larb_gen mtk_smi_larb_mt8183 = {
> - .need_larbid = true,
> .config_port = mtk_smi_larb_config_port_gen2_general,
> .larb_special_mask = BIT(2) | BIT(3) | BIT(7), /* IPU0 | IPU1 | CCU */
> };
> @@ -289,7 +276,6 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
> struct device *dev = &pdev->dev;
> struct device_node *smi_node;
> struct platform_device *smi_pdev;
> - int err;
>
> larb = devm_kzalloc(dev, sizeof(*larb), GFP_KERNEL);
> if (!larb)
> @@ -316,15 +302,6 @@ static int mtk_smi_larb_probe(struct platform_device *pdev)
> return PTR_ERR(larb->smi.clk_gals0);
> larb->smi.dev = dev;
>
> - if (larb->larb_gen->need_larbid) {
> - err = of_property_read_u32(dev->of_node, "mediatek,larb-id",
> - &larb->larbid);
> - if (err) {
> - dev_err(dev, "missing larbid property\n");
> - return err;
> - }
> - }
> -
> smi_node = of_parse_phandle(dev->of_node, "mediatek,smi", 0);
> if (!smi_node)
> return -EINVAL;
>