[PATCH 7/8] soc: mediatek: Add support for MTK_SCPD_STRICT_BUS_PROTECTION cap

From: Markus Schneider-Pargmann
Date: Thu Jan 05 2023 - 12:15:50 EST


From: Alexandre Bailon <abailon@xxxxxxxxxxxx>

This adds support for MTK_SCPD_STRICT_BUS_PROTECTION 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 v4:
- Change name in title and commit message

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 d53309f050ee..29a9028dd9b3 100644
--- a/drivers/soc/mediatek/mtk-pm-domains.c
+++ b/drivers/soc/mediatek/mtk-pm-domains.c
@@ -265,9 +265,17 @@ 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)
@@ -277,12 +285,23 @@ 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 1fa634509db1..e5aa2348a9db 100644
--- a/drivers/soc/mediatek/mtk-pm-domains.h
+++ b/drivers/soc/mediatek/mtk-pm-domains.h
@@ -11,6 +11,7 @@
/* can't set MTK_SCPD_KEEP_DEFAULT_OFF at the same time */
#define MTK_SCPD_ALWAYS_ON BIT(5)
#define MTK_SCPD_HAS_WAY_EN BIT(6)
+#define MTK_SCPD_STRICT_BUS_PROTECTION BIT(7)
#define MTK_SCPD_CAPS(_scpd, _x) ((_scpd)->data->caps & (_x))

#define SPM_VDE_PWR_CON 0x0210
--
2.39.0