2018-05-02 04:05:10

by Sean Wang

Subject: [PATCH v3] soc: mediatek: add a fixed wait for SRAM stable

From: Sean Wang <[email protected]>

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.

v2 -> v3:
- change the order for condition judgment with we check an existence of
the MTK_SCPD_FWAIT_SRAM first to get rid of any oversight on negative
condition.

Signed-off-by: Sean Wang <[email protected]>
Cc: Matthias Brugger <[email protected]>
Cc: Ulf Hansson <[email protected]>
Cc: Weiyi Lu <[email protected]>
---
drivers/soc/mediatek/mtk-scpsys.c | 23 +++++++++++++++++------
1 file changed, 17 insertions(+), 6 deletions(-)

diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
index b1b45e4..2080c8f 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 +238,21 @@ 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)) {
+ /*
+ * Currently, MTK_SCPD_FWAIT_SRAM is necessary only for
+ * MT7622_POWER_DOMAIN_WB and thus just a trivial setup is
+ * applied here.
+ */
+ usleep_range(12000, 12100);
+
+ } else {
+ 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;
+ };

if (scpd->data->bus_prot_mask) {
ret = mtk_infracfg_clear_bus_protection(scp->infracfg,
@@ -785,7 +796,7 @@ 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,
},
};

--
2.7.4

2018-05-03 07:13:08

by Matthias Brugger

Subject: Re: [PATCH v3] soc: mediatek: add a fixed wait for SRAM stable

On 05/02/2018 06:03 AM, [email protected] wrote:
> From: Sean Wang <[email protected]>
>
> 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.
>
> v2 -> v3:
> - change the order for condition judgment with we check an existence of
> the MTK_SCPD_FWAIT_SRAM first to get rid of any oversight on negative
> condition.
>
> Signed-off-by: Sean Wang <[email protected]>
> Cc: Matthias Brugger <[email protected]>
> Cc: Ulf Hansson <[email protected]>
> Cc: Weiyi Lu <[email protected]>
> ---

Now pused to v4.17-next/soc

Thanks a lot!
Matthias

> drivers/soc/mediatek/mtk-scpsys.c | 23 +++++++++++++++++------
> 1 file changed, 17 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/soc/mediatek/mtk-scpsys.c b/drivers/soc/mediatek/mtk-scpsys.c
> index b1b45e4..2080c8f 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 +238,21 @@ 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)) {
> + /*
> + * Currently, MTK_SCPD_FWAIT_SRAM is necessary only for
> + * MT7622_POWER_DOMAIN_WB and thus just a trivial setup is
> + * applied here.
> + */
> + usleep_range(12000, 12100);
> +
> + } else {
> + 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;
> + };
>
> if (scpd->data->bus_prot_mask) {
> ret = mtk_infracfg_clear_bus_protection(scp->infracfg,
> @@ -785,7 +796,7 @@ 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,
> },
> };
>
>