From mboxrd@z Thu Jan 1 00:00:00 1970 From: matthias.bgg@gmail.com (Matthias Brugger) Date: Fri, 27 Apr 2018 11:46:14 +0200 Subject: [PATCH v2 2/2] soc: mediatek: add a fixed wait for SRAM stable In-Reply-To: <1524476340.12322.14.camel@mtkswgap22> References: <2e16481e1477dfae0cfb24568d8111da81d92628.1524472331.git.sean.wang@mediatek.com> <0ef8e87ba7156e626d1a1a48388f222ce917099b.1524472331.git.sean.wang@mediatek.com> <51840588-96e4-2520-f3d7-a61e74da6814@gmail.com> <1524476340.12322.14.camel@mtkswgap22> Message-ID: <0ec15c8a-ca90-26c3-1ea6-00bf0d48b62a@gmail.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Sean, On 04/23/2018 11:39 AM, Sean Wang wrote: > 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)) { After having another look on the patch, could you change the order of the if: So that we check for the existence of the MTK_SCPD_FWAIT_SRAM and sleep and in the else branch we to the readl_poll_timeout. I think in the future this will make the code easier to understand as you can easily oversee the '!' negation in the if. Regards, Matthias >>> + 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, >>> }, >>> }; >>> >>> > >