From mboxrd@z Thu Jan 1 00:00:00 1970 From: sean.wang@mediatek.com (Sean Wang) Date: Mon, 23 Apr 2018 17:39:00 +0800 Subject: [PATCH v2 2/2] soc: mediatek: add a fixed wait for SRAM stable In-Reply-To: <51840588-96e4-2520-f3d7-a61e74da6814@gmail.com> References: <2e16481e1477dfae0cfb24568d8111da81d92628.1524472331.git.sean.wang@mediatek.com> <0ef8e87ba7156e626d1a1a48388f222ce917099b.1524472331.git.sean.wang@mediatek.com> <51840588-96e4-2520-f3d7-a61e74da6814@gmail.com> Message-ID: <1524476340.12322.14.camel@mtkswgap22> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 2018-04-23 at 11:31 +0200, Matthias Brugger wrote: > > On 04/23/2018 10:36 AM, sean.wang at 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. > > > > v1 -> v2: > > - use MTK_SCPD_FWAIT_SRAM flag as an indication requiring force waiting. > > > > Signed-off-by: Sean Wang > > Cc: Matthias Brugger > > Cc: Ulf Hansson > > Cc: Weiyi Lu > > --- > > drivers/soc/mediatek/mtk-scpsys.c | 24 ++++++++++++++++++------ > > 1 file changed, 18 insertions(+), 6 deletions(-) > > > > diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c > > index b1b45e4..d4f1a63 100644 > > --- a/drivers/soc/mediatek/mtk-scpsys.c > > +++ b/drivers/soc/mediatek/mtk-scpsys.c > > @@ -32,6 +32,7 @@ > > #define MTK_POLL_TIMEOUT (jiffies_to_usecs(HZ)) > > > > #define MTK_SCPD_ACTIVE_WAKEUP BIT(0) > > +#define MTK_SCPD_FWAIT_SRAM BIT(1) > > #define MTK_SCPD_CAPS(_scpd, _x) ((_scpd)->data->caps & (_x)) > > > > #define SPM_VDE_PWR_CON 0x0210 > > @@ -237,11 +238,22 @@ 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 (!MTK_SCPD_CAPS(scpd, MTK_SCPD_FWAIT_SRAM)) { > > + 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 { > > + /* > > + * Currently, MTK_SCPD_FWAIT_SRAM is necessary only for > > + * MT7622_POWER_DOMAIN_WB and thus just a trivial setup is > > + * applied here. If there're more domains which need to force > > + * waiting for its own pre-defined value, the duration should > > + * be coded in the caps field. > > + */ > > I would say, if necessary in the future we can add a switch statement here. > Other then that the patches look good. If you are OK, I'll just delete the last > sentence when applying the patch. > yes, it's okay for me. > Regards, > Matthias > > > + usleep_range(12000, 12100); > > + }; > > > > if (scpd->data->bus_prot_mask) { > > ret = mtk_infracfg_clear_bus_protection(scp->infracfg, > > @@ -785,7 +797,7 @@ static const struct scp_domain_data scp_domain_data_mt7622[] = { > > .sram_pdn_ack_bits = 0, > > .clk_id = {CLK_NONE}, > > .bus_prot_mask = MT7622_TOP_AXI_PROT_EN_WB, > > - .caps = MTK_SCPD_ACTIVE_WAKEUP, > > + .caps = MTK_SCPD_ACTIVE_WAKEUP | MTK_SCPD_FWAIT_SRAM, > > }, > > }; > > > >