[PATCH 07/17] soc: ti: pruss: enable OCP master ports in SYSCFG always

[Roger Quadros <rogerq@ti.com>]

From: Suman Anna <s-anna@ti.com>

The PRUSS CFG module's SYSCFG register is used for managing the
PRCM clock management settings at the PRU-ICSS subsystem level,
and is being programmed for the PRCM Idle/Standby protocol properly
during probe and remove. The register is also programmed to enable
the OCP master ports (disable MStandby) by default during probe now
to allow the PRUs access to on-chip memories and peripherals outside
the PRUSS without having to do it in firmware (primarily for the PRU
Ethernet usecase currently, the firmware is not programming this
register).

NOTE:
1. The AM57xx TRM suggests to enable "No Standby" during the
   Idle + Standby state to an Active/Normal state, but this
   sequence is not documented in either of AM33xx and AM437x
   SoCs. Furthermore, it did not have an impact on the working
   of Ethernet Rx, so is left out.
2. This has an impact on the PM suspend/resume operation usually
   (same bit is used to trigger PRU standby), and even when the
   PRU cores are in halted state. The STANDBY_INIT has to be
   re-programmed to initiate a standby sequence and have the PM
   suspend/resume functional when PRUs are halted. This is already
   handled in commit b7e68ab66385 ("remoteproc/pruss_soc: fix system
   suspend/MStandby config issues").

Signed-off-by: Suman Anna <s-anna@ti.com>
---
 drivers/soc/ti/pruss_soc_bus.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/drivers/soc/ti/pruss_soc_bus.c b/drivers/soc/ti/pruss_soc_bus.c
index 46dfb7a..f477168 100644
--- a/drivers/soc/ti/pruss_soc_bus.c
+++ b/drivers/soc/ti/pruss_soc_bus.c
@@ -67,8 +67,7 @@ static inline void pruss_soc_bus_rmw(void __iomem *reg, u32 mask, u32 set)
  * outside of the PRU-ICSS. The function has to wait for the PRCM to
  * acknowledge through the monitoring of the PRUSS_SYSCFG.SUB_MWAIT bit.
  */
-static
-int __maybe_unused pruss_soc_bus_enable_ocp_master_ports(struct device *dev)
+static int pruss_soc_bus_enable_ocp_master_ports(struct device *dev)
 {
 	struct pruss_soc_bus *psoc_bus = dev_get_drvdata(dev);
 	u32 syscfg_val, i;
@@ -160,6 +159,11 @@ static int pruss_enable_module(struct device *dev)
 	pruss_soc_bus_rmw(psoc_bus->syscfg, SYSCFG_STANDBY_MODE_MASK,
 			  SYSCFG_STANDBY_MODE_SMART);
 
+	/* enable OCP master ports/disable MStandby */
+	ret = pruss_soc_bus_enable_ocp_master_ports(dev);
+	if (ret)
+		pruss_disable_module(dev);
+
 	return ret;
 }
 
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