Re: [PATCH v14 07/12] remoteproc: mediatek: Remove dependency of MT8195 SCP L2TCM power control on dual-core SCP
From: Mathieu Poirier
Date: Tue Jul 11 2023 - 14:00:19 EST
On Tue, Jul 11, 2023 at 11:50:03AM -0600, Mathieu Poirier wrote:
> On Fri, Jul 07, 2023 at 01:26:07PM +0800, Tinghan Shen wrote:
> > Previously, SCP core 0 controlled the power of L2TCM and dictated that
> > SCP core 1 could only boot after SCP core 0. To address this constraint,
> > extracted the power control flow of L2TCM and made it shared
> > between both cores, enabling support of arbitrary boot order.
>
> Definitely an improvement.
>
> >
> > The flow for controlling L2TCM power has been incorporated into the
> > mt8195_scp_before_load() and mt8195_scp_stop() APIs, which are
> > respectively invoked during the rproc->ops->start() and
> > rproc->ops->stop() operations. These APIs effectively serve the same
> > purpose as the rproc prepare()/unprepare() APIs."
>
> I'm not fond of that custom API but it is so widespread in this driver that I
> will go with it.
>
> >
> > Signed-off-by: Tinghan Shen <tinghan.shen@xxxxxxxxxxxx>
> > ---
> > drivers/remoteproc/mtk_common.h | 1 +
> > drivers/remoteproc/mtk_scp.c | 80 ++++++++++++++++++++++++++-------
> > 2 files changed, 66 insertions(+), 15 deletions(-)
> >
> > diff --git a/drivers/remoteproc/mtk_common.h b/drivers/remoteproc/mtk_common.h
> > index 56395e8664cb..41e1b4732b75 100644
> > --- a/drivers/remoteproc/mtk_common.h
> > +++ b/drivers/remoteproc/mtk_common.h
> > @@ -130,6 +130,7 @@ struct mtk_scp {
> > struct rproc_subdev *rpmsg_subdev;
> >
> > struct list_head elem;
> > + struct platform_device *cluster_pdev;
>
> This isn't needed. rproc->dev.parent is pdev->dev. Use container_of() to
> get to the platform device.
>
>
> > };
> >
> > /**
> > diff --git a/drivers/remoteproc/mtk_scp.c b/drivers/remoteproc/mtk_scp.c
> > index 3349488e5f21..94602272c05f 100644
> > --- a/drivers/remoteproc/mtk_scp.c
> > +++ b/drivers/remoteproc/mtk_scp.c
> > @@ -29,6 +29,10 @@ struct mtk_scp_of_cluster {
> > size_t l1tcm_size;
> > phys_addr_t l1tcm_phys;
> > struct list_head mtk_scp_list;
> > +
> > + /* Prevent concurrent operations of L2TCM power control. */
> > + struct mutex l2tcm_lock;
> > + u32 l2tcm_refcnt;
> > };
> >
> > /**
> > @@ -449,7 +453,7 @@ static int mt8192_scp_before_load(struct mtk_scp *scp)
> >
> > writel(1, scp->reg_base + MT8192_CORE0_SW_RSTN_SET);
> >
> > - /* enable SRAM clock */
> > + /* enable SRAM power */
> > scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
> > scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
> > scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
> > @@ -462,19 +466,38 @@ static int mt8192_scp_before_load(struct mtk_scp *scp)
> > return 0;
> > }
> >
> > -static int mt8195_scp_before_load(struct mtk_scp *scp)
> > +static int mt8195_scp_l2tcm_on(struct mtk_scp *scp)
> > {
> > - /* clear SPM interrupt, SCP2SPM_IPC_CLR */
> > - writel(0xff, scp->reg_base + MT8192_SCP2SPM_IPC_CLR);
> > + struct mtk_scp_of_cluster *scp_cluster = platform_get_drvdata(scp->cluster_pdev);
> > +
> > + mutex_lock(&scp_cluster->l2tcm_lock);
> > +
> > + if (scp_cluster->l2tcm_refcnt == 0) {
> > + /* clear SPM interrupt, SCP2SPM_IPC_CLR */
> > + writel(0xff, scp->reg_base + MT8192_SCP2SPM_IPC_CLR);
> > +
> > + /* Power on L2TCM */
> > + scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
> > + scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
> > + scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
> > + scp_sram_power_on(scp->reg_base + MT8192_L1TCM_SRAM_PDN,
> > + MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS);
> > + }
> > +
> > + scp_cluster->l2tcm_refcnt += 1;
> >
> > + mutex_unlock(&scp_cluster->l2tcm_lock);
> > +
> > + return 0;
> > +}
> > +
> > +static int mt8195_scp_before_load(struct mtk_scp *scp)
> > +{
> > writel(1, scp->reg_base + MT8192_CORE0_SW_RSTN_SET);
> >
> > + mt8195_scp_l2tcm_on(scp);
> > +
> > /* enable SRAM clock */
> > - scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
> > - scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
> > - scp_sram_power_on(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
> > - scp_sram_power_on(scp->reg_base + MT8192_L1TCM_SRAM_PDN,
> > - MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS);
> > scp_sram_power_on(scp->reg_base + MT8192_CPU0_SRAM_PD, 0);
> >
> > /* enable MPU for all memory regions */
> > @@ -487,6 +510,8 @@ static int mt8195_scp_c1_before_load(struct mtk_scp *scp)
> > {
> > scp->data->scp_reset_assert(scp);
> >
> > + mt8195_scp_l2tcm_on(scp);
> > +
> > scp_sram_power_on(scp->reg_base + MT8195_CPU1_SRAM_PD, 0);
> >
> > /* enable MPU for all memory regions */
> > @@ -653,14 +678,30 @@ static void mt8192_scp_stop(struct mtk_scp *scp)
> > writel(0, scp->reg_base + MT8192_CORE0_WDT_CFG);
> > }
> >
> > +static void mt8195_scp_l2tcm_off(struct mtk_scp *scp)
> > +{
> > + struct mtk_scp_of_cluster *scp_cluster = platform_get_drvdata(scp->cluster_pdev);
> > +
> > + mutex_lock(&scp_cluster->l2tcm_lock);
> > +
>
> What happens if ->l2tcm_refcnt is 0 and this function is called?
>
More comments to come tomorrow.
Thanks,
Mathieu
>
> > + scp_cluster->l2tcm_refcnt -= 1;
> > +
> > + if (scp_cluster->l2tcm_refcnt == 0) {
> > + /* Power off L2TCM */
> > + scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
> > + scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
> > + scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
> > + scp_sram_power_off(scp->reg_base + MT8192_L1TCM_SRAM_PDN, 0);
> > + scp_sram_power_off(scp->reg_base + MT8192_CPU0_SRAM_PD, 0);
> > + }
> > +
> > + mutex_unlock(&scp_cluster->l2tcm_lock);
> > +}
> > +
> > static void mt8195_scp_stop(struct mtk_scp *scp)
> > {
> > - /* Disable SRAM clock */
> > - scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_0, 0);
> > - scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_1, 0);
> > - scp_sram_power_off(scp->reg_base + MT8192_L2TCM_SRAM_PD_2, 0);
> > - scp_sram_power_off(scp->reg_base + MT8192_L1TCM_SRAM_PDN,
> > - MT8195_L1TCM_SRAM_PDN_RESERVED_RSI_BITS);
> > + mt8195_scp_l2tcm_off(scp);
> > +
> > scp_sram_power_off(scp->reg_base + MT8192_CPU0_SRAM_PD, 0);
> >
> > /* Disable SCP watchdog */
> > @@ -669,6 +710,8 @@ static void mt8195_scp_stop(struct mtk_scp *scp)
> >
> > static void mt8195_scp_c1_stop(struct mtk_scp *scp)
> > {
> > + mt8195_scp_l2tcm_off(scp);
> > +
> > /* Power off CPU SRAM */
> > scp_sram_power_off(scp->reg_base + MT8195_CPU1_SRAM_PD, 0);
> >
> > @@ -976,6 +1019,8 @@ static int scp_add_single_core(struct platform_device *pdev)
> > if (IS_ERR(scp))
> > return PTR_ERR(scp);
> >
> > + scp->cluster_pdev = pdev;
> > +
> > ret = rproc_add(scp->rproc);
> > if (ret) {
> > dev_err(dev, "Failed to add rproc\n");
> > @@ -1028,6 +1073,8 @@ static int scp_add_multi_core(struct platform_device *pdev)
> > goto init_fail;
> > }
> >
> > + scp->cluster_pdev = pdev;
> > +
> > ret = rproc_add(scp->rproc);
> > if (ret) {
> > dev_err(dev, "Failed to add rproc of core %d\n", core_id);
> > @@ -1114,6 +1161,7 @@ static int scp_probe(struct platform_device *pdev)
> > }
> >
> > INIT_LIST_HEAD(&scp_cluster->mtk_scp_list);
> > + mutex_init(&scp_cluster->l2tcm_lock);
> > platform_set_drvdata(pdev, scp_cluster);
> >
> > ret = devm_of_platform_populate(dev);
> > @@ -1137,6 +1185,8 @@ static void scp_remove(struct platform_device *pdev)
> > rproc_del(scp->rproc);
> > scp_free(scp);
> > }
> > +
> > + mutex_destroy(&scp_cluster->l2tcm_lock);
> > }
> >
> > static const struct mtk_scp_of_data mt8183_of_data = {
> > --
> > 2.18.0
> >