ARM: OMAP2PLUS: DSS hwmod fixes

The clocks for all DSS slave interfaces were recently changed to "dss_ick" on OMAP2 and OMAP3, this clock can be autoidled by PRCM. The VENC interface previously had "dss_54m_fck" as it's clock which couldn't be autoidled, and hence the OCPIF_SWSUP_IDLE flag was needed.

Remove the OCPIF_SWSUP_IDLE flag from VENC interfaces as it's clock is now "dss_ick".

Signed-off-by Archit Taneja <[email protected]>

Quoted 5 lines · Archit Taneja

The clocks for all DSS slave interfaces were recently changed to "dss_ick" on OMAP2 and OMAP3, this clock can be autoidled by PRCM. The VENC interface previously had "dss_54m_fck" as it's clock which couldn't be autoidled, and hence the OCPIF_SWSUP_IDLE flag was needed.

Quoted 4 lines

Remove the OCPIF_SWSUP_IDLE flag from VENC interfaces as it's clock is now "dss_ick".

Signed-off-by Archit Taneja <[email protected]>

Thanks, queued for 3.4-rc.

Quoted 10 lines · Paul Walmsley

Quoted 8 lines · Archit Taneja

The clocks for all DSS slave interfaces were recently changed to "dss_ick" on OMAP2 and OMAP3, this clock can be autoidled by PRCM. The VENC interface previously had "dss_54m_fck" as it's clock which couldn't be autoidled, and hence the OCPIF_SWSUP_IDLE flag was needed.

Remove the OCPIF_SWSUP_IDLE flag from VENC interfaces as it's clock is now "dss_ick".

Quoted 3 lines

Quoted 1 line

Signed-off-by Archit Taneja<[email protected]>

Thanks, queued for 3.4-rc.

By the way, I added another sentence to the commit log to describe what is being fixed. Please let me know if you have any comments.

- Paul

From: Archit Taneja<[email protected]>
Date: Fri, 13 Apr 2012 13:31:55 +0530
Subject: [PATCH 3/3] ARM: OMAP2/3: VENC hwmods: Remove OCPIF_SWSUP_IDLE flag
from VENC slave interface

The clocks for all DSS slave interfaces were recently changed to "dss_ick" on OMAP2 and OMAP3, this clock can be autoidled by PRCM. The VENC interface previously had "dss_54m_fck" as it's clock which couldn't be autoidled, and hence the OCPIF_SWSUP_IDLE flag was needed.

Remove the OCPIF_SWSUP_IDLE flag from VENC interfaces as it's clock is now "dss_ick". This allows the PRCM hardware to autoidle the VENC interface clocks when they are not active, rather than relying on the software to do it, which can keep the interface clocks active unnecessarily.

Signed-off-by Archit Taneja<[email protected]>

[paul at pwsan.com: add a short description of the fix to the commit log]

Signed-off-by Paul Walmsley<[email protected]>

---
  arch/arm/mach-omap2/omap_hwmod_2420_data.c |    1 -
  arch/arm/mach-omap2/omap_hwmod_2430_data.c |    1 -
  arch/arm/mach-omap2/omap_hwmod_3xxx_data.c |    1 -
  3 files changed, 3 deletions(-)

arch/arm/mach-omap2/omap_hwmod_2420_data.c +0 -1

index a5409ce..a6bde34 100644
@@ -1000,7 +1000,6 @@ static struct omap_hwmod_ocp_if omap2420_l4_core__dss_venc = {
  			.flags	= OMAP_FIREWALL_L4,
  		}
  	},
-	.flags		= OCPIF_SWSUP_IDLE,
  	.user		= OCP_USER_MPU | OCP_USER_SDMA,
  };
 

arch/arm/mach-omap2/omap_hwmod_2430_data.c +0 -1

index c4f56cb..04a3885 100644
@@ -1049,7 +1049,6 @@ static struct omap_hwmod_ocp_if omap2430_l4_core__dss_venc = {
  	.slave		=&omap2430_dss_venc_hwmod,
  	.clk		= "dss_ick",
  	.addr		= omap2_dss_venc_addrs,
-	.flags		= OCPIF_SWSUP_IDLE,
  	.user		= OCP_USER_MPU | OCP_USER_SDMA,
  };
 

arch/arm/mach-omap2/omap_hwmod_3xxx_data.c +0 -1

index 34b9766d..db86ce9 100644
@@ -1676,7 +1676,6 @@ static struct omap_hwmod_ocp_if omap3xxx_l4_core__dss_venc = {
  			.flags	= OMAP_FIREWALL_L4,
  		}
  	},
-	.flags		= OCPIF_SWSUP_IDLE,
  	.user		= OCP_USER_MPU | OCP_USER_SDMA,
  };
 

The clock for all DSS L3 slave interfaces had been recently changed to "dss_fck" from "l3_div_ck". "dss_fck" is an optional clock in DSS clock domain which can't autoidle when enabled.

Add OCPIF_SWSUP_IDLE flag to all the L3 slave interfaces used by DSS hwmods so that clock is explicitly enabled and disabled by software. Without this, "dss_fck" would be left as enabled and the OMAP4 device won't idle even when DSS is not in use.

Quoted 11 lines · Archit Taneja

The clock for all DSS L3 slave interfaces had been recently changed to "dss_fck" from "l3_div_ck". "dss_fck" is an optional clock in DSS clock domain
which can't autoidle when enabled.

Add OCPIF_SWSUP_IDLE flag to all the L3 slave interfaces used by DSS hwmods so
that clock is explicitly enabled and disabled by software. Without this, "dss_fck" would be left as enabled and the OMAP4 device won't idle even when
DSS is not in use.

Yeah, that was done on purpose with Tomi knowning well that limitation.

The issue was mainly due to the lack of proper parent / child relationship between the DSS (the whole subsystem) and the DSS children at that time.

I think that Tomi posted a series to fix that for 3.4. So if we ensure that every DSS IPs are children of the DSS, then pm_runtime will always ensure that the DSS will be enabled each time a submodule is used.

So the right fix is to put back the proper iclk (l3_div) to the DSS instead of the dss_fck.

The current OMAP4 DSS clock setup is clearly a hack that should be fixed.

Regards,
Benoit

Quoted 23 lines · Benoit

Quoted 11 lines · Archit Taneja

The clock for all DSS L3 slave interfaces had been recently changed to "dss_fck" from "l3_div_ck". "dss_fck" is an optional clock in DSS clock domain
which can't autoidle when enabled.

Add OCPIF_SWSUP_IDLE flag to all the L3 slave interfaces used by DSS hwmods so
that clock is explicitly enabled and disabled by software. Without this, "dss_fck" would be left as enabled and the OMAP4 device won't idle even when
DSS is not in use.

Yeah, that was done on purpose with Tomi knowning well that limitation.

The issue was mainly due to the lack of proper parent / child relationship between the DSS (the whole subsystem) and the DSS children at that time.

I think that Tomi posted a series to fix that for 3.4. So if we ensure that every DSS IPs are children of the DSS, then pm_runtime will always ensure that the DSS will be enabled each time a submodule is used.

Quoted 2 lines

So the right fix is to put back the proper iclk (l3_div) to the DSS instead of the dss_fck.

Ok, I get it now. Tomi's patch series ensured the parent-child dependency, but they didn't switch the iclks back to l3_div, I guess that should be a part of the series too.

Hi Archit,

Quoted 24 lines · Archit Taneja

Quoted 23 lines · Benoit

Quoted 11 lines · Archit Taneja

The clock for all DSS L3 slave interfaces had been recently changed to "dss_fck" from "l3_div_ck". "dss_fck" is an optional clock in DSS clock domain
which can't autoidle when enabled.

Add OCPIF_SWSUP_IDLE flag to all the L3 slave interfaces used by DSS hwmods so
that clock is explicitly enabled and disabled by software. Without this, "dss_fck" would be left as enabled and the OMAP4 device won't idle even when
DSS is not in use.

Yeah, that was done on purpose with Tomi knowning well that limitation.

The issue was mainly due to the lack of proper parent / child relationship between the DSS (the whole subsystem) and the DSS children at that time.

I think that Tomi posted a series to fix that for 3.4. So if we ensure that every DSS IPs are children of the DSS, then pm_runtime will always ensure that the DSS will be enabled each time a submodule is used.

Quoted 6 lines

Quoted 2 lines

So the right fix is to put back the proper iclk (l3_div) to the DSS instead of the dss_fck.

Ok, I get it now. Tomi's patch series ensured the parent-child dependency, but they didn't switch the iclks back to l3_div, I guess that should be a part of the series too.

Just checking on this one. Does this patch need to be updated ?

- Paul

Hi Paul,

Quoted 28 lines · Paul Walmsley

Hi Archit,

Quoted 24 lines · Archit Taneja

Quoted 23 lines · Benoit

Quoted 11 lines · Archit Taneja

The clock for all DSS L3 slave interfaces had been recently changed to "dss_fck" from "l3_div_ck". "dss_fck" is an optional clock in DSS clock domain
which can't autoidle when enabled.

Add OCPIF_SWSUP_IDLE flag to all the L3 slave interfaces used by DSS hwmods so
that clock is explicitly enabled and disabled by software. Without this, "dss_fck" would be left as enabled and the OMAP4 device won't idle even when
DSS is not in use.

Yeah, that was done on purpose with Tomi knowning well that limitation.

The issue was mainly due to the lack of proper parent / child relationship between the DSS (the whole subsystem) and the DSS children at that time.

I think that Tomi posted a series to fix that for 3.4. So if we ensure that every DSS IPs are children of the DSS, then pm_runtime will always ensure that the DSS will be enabled each time a submodule is used.

Quoted 9 lines

Quoted 6 lines

Quoted 2 lines

So the right fix is to put back the proper iclk (l3_div) to the DSS instead of the dss_fck.

Ok, I get it now. Tomi's patch series ensured the parent-child dependency, but they didn't switch the iclks back to l3_div, I guess that should be a part of the series too.

Just checking on this one. Does this patch need to be updated ?

We were working on this, but we realised that only having a parent-child relation in dss platform devices won't be sufficient to remove "the use of dss_fck(or MODULEMODE bits) as a slave clock" hack.

The issue is that during bootup(when omap_hwmod_setup_all() is called), all hwmods are enabled independently, so all dss hwmods need to enable the MODULEMODE bits for them to be setup correctly.

With the parent-child relation in platform devices in DSS, only the parent platform device's hwmod("dss_core" in our case) should enable and disable the MODULEMODE bits. If the children also become capable of enabling/disabling it, then things wouldn't work.

Hence, to go ahead with this approach, the hwmod's themselves need to have some sort of parent child relationship, or atleast some sort of use counting for MODULEMODE bits. Benoit and Tomi could comment more on this.

Hence we are sort of stuck :)