Return-Path: Subject: Re: [PATCH v1 5/7] soc: mediatek: add a fixed wait for SRAM stable To: sean.wang@mediatek.com, robh+dt@kernel.org, mark.rutland@arm.com, marcel@holtmann.org, johan.hedberg@gmail.com Cc: devicetree@vger.kernel.org, linux-bluetooth@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org, linux-kernel@vger.kernel.org, Ulf Hansson , Weiyi Lu References: <0fc10b2498c6dbe20141831c722c32cc74330d3d.1522736996.git.sean.wang@mediatek.com> From: Matthias Brugger Message-ID: <5f2530a0-aee2-39fe-eb5c-56cd4a68c9db@gmail.com> Date: Thu, 19 Apr 2018 12:33:37 +0200 MIME-Version: 1.0 In-Reply-To: <0fc10b2498c6dbe20141831c722c32cc74330d3d.1522736996.git.sean.wang@mediatek.com> Content-Type: text/plain; charset=utf-8 List-ID: On 04/03/2018 09:15 AM, sean.wang@mediatek.com wrote: > From: Sean Wang > > MT7622_POWER_DOMAIN_WB doesn't send an ACK when its managed SRAM becomes > stable, which is not like the behavior the other power domains should > have. Therefore, it's necessary for such a power domain to have a fixed > and well-predefined duration to wait until its managed SRAM can be allowed > to access by all functions running on the top. > > Signed-off-by: Sean Wang > Cc: Matthias Brugger > Cc: Ulf Hansson > Cc: Weiyi Lu > --- > drivers/soc/mediatek/mtk-scpsys.c | 17 ++++++++++++----- > 1 file changed, 12 insertions(+), 5 deletions(-) > > diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c > index f9b7248..19aceb8 100644 > --- a/drivers/soc/mediatek/mtk-scpsys.c > +++ b/drivers/soc/mediatek/mtk-scpsys.c > @@ -121,6 +121,7 @@ struct scp_domain_data { > u32 bus_prot_mask; > enum clk_id clk_id[MAX_CLKS]; > bool active_wakeup; > + u32 us_sram_fwait; Before adding more and more fields to scp_domain_data which get checked in if's, I'd prefer to add a caps field used for bus_prot_mask, active_wakeup in a first patch and add the cap FORCE_WAIT in a second patch. Can you help to implement this Sean, or shall I give it a try? Regards, Matthias > }; > > struct scp; > @@ -234,11 +235,16 @@ static int scpsys_power_on(struct generic_pm_domain *genpd) > val &= ~scpd->data->sram_pdn_bits; > writel(val, ctl_addr); > > - /* wait until SRAM_PDN_ACK all 0 */ > - ret = readl_poll_timeout(ctl_addr, tmp, (tmp & pdn_ack) == 0, > - MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT); > - if (ret < 0) > - goto err_pwr_ack; > + /* Either wait until SRAM_PDN_ACK all 0 or have a force wait */ > + if (!scpd->data->us_sram_fwait) { > + ret = readl_poll_timeout(ctl_addr, tmp, (tmp & pdn_ack) == 0, > + MTK_POLL_DELAY_US, MTK_POLL_TIMEOUT); > + if (ret < 0) > + goto err_pwr_ack; > + } else { > + usleep_range(scpd->data->us_sram_fwait, > + scpd->data->us_sram_fwait + 100); > + }; > > if (scpd->data->bus_prot_mask) { > ret = mtk_infracfg_clear_bus_protection(scp->infracfg, > @@ -783,6 +789,7 @@ static const struct scp_domain_data scp_domain_data_mt7622[] = { > .clk_id = {CLK_NONE}, > .bus_prot_mask = MT7622_TOP_AXI_PROT_EN_WB, > .active_wakeup = true, > + .us_sram_fwait = 12000, > }, > }; > >