From mboxrd@z Thu Jan 1 00:00:00 1970 From: matthias.bgg@gmail.com (Matthias Brugger) Date: Mon, 23 Apr 2018 11:31:36 +0200 Subject: [PATCH v2 2/2] soc: mediatek: add a fixed wait for SRAM stable In-Reply-To: <0ef8e87ba7156e626d1a1a48388f222ce917099b.1524472331.git.sean.wang@mediatek.com> References: <2e16481e1477dfae0cfb24568d8111da81d92628.1524472331.git.sean.wang@mediatek.com> <0ef8e87ba7156e626d1a1a48388f222ce917099b.1524472331.git.sean.wang@mediatek.com> Message-ID: <51840588-96e4-2520-f3d7-a61e74da6814@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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. 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, > }, > }; > >