[PATCH v3 3/4] soc: mediatek: add support of MTK_SCPD_STRICT_BUSP cap

From: Markus Schneider-Pargmann
Date: Mon Aug 22 2022 - 10:47:24 EST


From: Alexandre Bailon <abailon@xxxxxxxxxxxx>

This adds support for MTK_SCPD_STRICT_BUSP capability. It is a strict
bus protection policy that requires the bus protection to be disabled
before accessing the bus.
This is required by the mt8365, for the MM power domain.

Signed-off-by: Alexandre Bailon <abailon@xxxxxxxxxxxx>
Signed-off-by: Fabien Parent <fparent@xxxxxxxxxxxx>
Signed-off-by: Markus Schneider-Pargmann <msp@xxxxxxxxxxxx>
---

Notes:
Changes in v3:
- Rename MTK_SCPD_STRICT_BUSP to MTK_SCPD_STRICT_BUS_PROTECTION
- Remove extra bool variable reflecting the capability

Changes in v2:
- Fixup error handling path.

drivers/soc/mediatek/mtk-pm-domains.c | 27 +++++++++++++++++++++++----
drivers/soc/mediatek/mtk-pm-domains.h | 1 +
2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/drivers/soc/mediatek/mtk-pm-domains.c b/drivers/soc/mediatek/mtk-pm-domains.c
index c2cbe0de6aa1..d323275aa11c 100644
--- a/drivers/soc/mediatek/mtk-pm-domains.c
+++ b/drivers/soc/mediatek/mtk-pm-domains.c
@@ -303,9 +303,17 @@ static int scpsys_power_on(struct generic_pm_domain *genpd)
regmap_clear_bits(scpsys->base, pd->data->ctl_offs, PWR_ISO_BIT);
regmap_set_bits(scpsys->base, pd->data->ctl_offs, PWR_RST_B_BIT);

- ret = clk_bulk_prepare_enable(pd->num_subsys_clks, pd->subsys_clks);
- if (ret)
- goto err_pwr_ack;
+ /*
+ * In few Mediatek platforms(e.g. MT6779), the bus protect policy is
+ * stricter, which leads to bus protect release must be prior to bus
+ * access.
+ */
+ if (!MTK_SCPD_CAPS(pd, MTK_SCPD_STRICT_BUS_PROTECTION)) {
+ ret = clk_bulk_prepare_enable(pd->num_subsys_clks,
+ pd->subsys_clks);
+ if (ret)
+ goto err_pwr_ack;
+ }

ret = scpsys_sram_enable(pd);
if (ret < 0)
@@ -315,12 +323,23 @@ static int scpsys_power_on(struct generic_pm_domain *genpd)
if (ret < 0)
goto err_disable_sram;

+ if (MTK_SCPD_CAPS(pd, MTK_SCPD_STRICT_BUS_PROTECTION)) {
+ ret = clk_bulk_prepare_enable(pd->num_subsys_clks,
+ pd->subsys_clks);
+ if (ret)
+ goto err_enable_bus_protect;
+ }
+
return 0;

+err_enable_bus_protect:
+ scpsys_bus_protect_enable(pd);
err_disable_sram:
scpsys_sram_disable(pd);
err_disable_subsys_clks:
- clk_bulk_disable_unprepare(pd->num_subsys_clks, pd->subsys_clks);
+ if (!MTK_SCPD_CAPS(pd, MTK_SCPD_STRICT_BUS_PROTECTION))
+ clk_bulk_disable_unprepare(pd->num_subsys_clks,
+ pd->subsys_clks);
err_pwr_ack:
clk_bulk_disable_unprepare(pd->num_clks, pd->clks);
err_reg:
diff --git a/drivers/soc/mediatek/mtk-pm-domains.h b/drivers/soc/mediatek/mtk-pm-domains.h
index 974c68a1d89c..493f3fa14612 100644
--- a/drivers/soc/mediatek/mtk-pm-domains.h
+++ b/drivers/soc/mediatek/mtk-pm-domains.h
@@ -10,6 +10,7 @@
#define MTK_SCPD_DOMAIN_SUPPLY BIT(4)
/* can't set MTK_SCPD_KEEP_DEFAULT_OFF at the same time */
#define MTK_SCPD_ALWAYS_ON BIT(5)
+#define MTK_SCPD_STRICT_BUS_PROTECTION BIT(6)
#define MTK_SCPD_CAPS(_scpd, _x) ((_scpd)->data->caps & (_x))

#define SPM_VDE_PWR_CON 0x0210
--
2.37.2