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Subject[PATCH v1 5/7] soc: mediatek: add a fixed wait for SRAM stable
Date
From: Sean Wang <sean.wang@mediatek.com>

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 <sean.wang@mediatek.com>
Cc: Matthias Brugger <matthias.bgg@gmail.com>
Cc: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Weiyi Lu <weiyi.lu@mediatek.com>
---
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;
};

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,
},
};

--
2.7.4
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