Re: [RFC][PATCH 2/2] OMAP4: PRCM: Fix usage of prm/cm accessor api's for OMAP4

"Cousson, Benoit" <b-cousson@xxxxxx> · Fri, 15 Oct 2010 18:07:21 +0200

Hi Paul,

On 10/14/2010 8:44 PM, Paul Walmsley wrote:
Hello Rajendra,

On Tue, 10 Aug 2010, Rajendra Nayak wrote:

OMAP's have always had PRCM split into PRM for power and reset
management and CM for clock management.
In OMAP4 the split (physically) is not very straight forward and
there are instances of clock management control registers in PRM
and vice versa.
However it still makes sense, even on OMAP4 to logically split
PRCM into PRM and CM for better understanding and to avoid adding
additonal complexity in higher level frameworks which rely on the
accessor api;s to do the low level register accesses.

Hence this patch makes sure that any clock management code can
use the cm_read/write* accessor apis (without knowing the physical split)
and power and reset management code can use prm_read/write*
accessor api;s.

To do this the submodule offsets within PRM/CM1 and CM2 have additonal
info embedded in them specifying what base address to use while
trying to access registers in the given submodule.

The 16 bit signed submodule offset is defined for OMAP4 as
<Bit 15>	|<Bit 14:13>  		|<Bit 12:0>
<Sign bit>	|<base identifier>	|<submodule offset from base>

The concern that I have with embedding multiple parameters into a single
parameter is that it seems like a hack.  Why not add an extra parameter
for the base identifier, rather than packing it into an existing
parameter?

The primary constraint that lead us to that proposal was to minimize the 
impact on the existing code and API for previous OMAPs.
That was clearly the goal #1.
The other one was the relative simplicity of the implementation.

The user of these OMAP4430_XXXX_MOD macros does not have to care if this 
is a real offset or just an id.

I am not necessarily opposed to your patch as it exists.  But I would like
to hear your opinions first on separating out the base identifier
parameter as a separate function parameter, and then adding an extra field
for it into any data structure that would need it.  Could you write
briefly if you see any significant advantages/disadvantages to that
approach?

The disadvantage is the relative complexity for the caller of this API, 
that will have to know what partition should be used.
It is fine if the caller is the powerdomain or clockdomain fmwk, but 
what about all the other callers we have here and there?
When we looked at that in Bangalore, we realized that a bunch of code is 
using these prm/cm APIs. Maybe some cleanup can be done, like in the 
save / restore part, but we still have some user of that.

For the moment, I do not really see any advantage of such approach.
The partitioning is changing on every OMAPs, so we do have to abstract 
that. If it is not done at that level, we will have to define another 
API on top of that to do exactly the same job.


Regards,
Benoit


For older OMAP's the base identifier is always set to 0.

Signed-off-by: Rajendra Nayak<rnayak@xxxxxx>
Cc: Kevin Hilman<khilman@xxxxxxxxxxxxxxxxxxx>
Cc: Paul Walmsley<paul@xxxxxxxxx>
Cc: Benoit Cousson<b-cousson@xxxxxx>
---
  arch/arm/mach-omap2/cm.h          |    4 +-
  arch/arm/mach-omap2/prcm-common.h |   58 ++++++++++++++++++++-----------
  arch/arm/mach-omap2/prcm.c        |   68 ++++++++++++++++++++++++++++++++++--
  arch/arm/mach-omap2/prm.h         |    4 +-
  4 files changed, 105 insertions(+), 29 deletions(-)

diff --git a/arch/arm/mach-omap2/cm.h b/arch/arm/mach-omap2/cm.h
index a02ca30..7b7ef09 100644
--- a/arch/arm/mach-omap2/cm.h
+++ b/arch/arm/mach-omap2/cm.h
@@ -23,9 +23,9 @@
  #define OMAP34XX_CM_REGADDR(module, reg)				\
  			OMAP2_L4_IO_ADDRESS(OMAP3430_CM_BASE + (module) + (reg))
  #define OMAP44XX_CM1_REGADDR(module, reg)				\
-			OMAP2_L4_IO_ADDRESS(OMAP4430_CM1_BASE + (module) + (reg))
+			OMAP2_L4_IO_ADDRESS(OMAP4430_CM1_BASE + ((module)&  (MOD_MASK)) + (reg))
  #define OMAP44XX_CM2_REGADDR(module, reg)				\
-			OMAP2_L4_IO_ADDRESS(OMAP4430_CM2_BASE + (module) + (reg))
+			OMAP2_L4_IO_ADDRESS(OMAP4430_CM2_BASE + ((module)&  (MOD_MASK)) + (reg))

  #include "cm44xx.h"

diff --git a/arch/arm/mach-omap2/prcm-common.h b/arch/arm/mach-omap2/prcm-common.h
index 995b7ed..b93d33e 100644
--- a/arch/arm/mach-omap2/prcm-common.h
+++ b/arch/arm/mach-omap2/prcm-common.h
@@ -57,10 +57,26 @@
  #define BITFIELD(l_bit, u_bit)	\
  	(BITS(u_bit)&  ~((BITS(l_bit))>>  1))

-/* OMAP44XX specific module offsets */
+/*
+ * OMAP44XX specific module offsets
+ * The 16 bit submodule offset is defined for OMAP4 as
+ *<Bit 15>	|<Bit 14:13>  		|<Bit 12:0>
+ *<Sign bit>	|<base identifier>	|<submodule offset from base>
+ */

-/* CM1 instances */
+#define DEFAULT_BASE	0x0
+#define PRM_BASE	0x1
+#define PRCM_MPU_BASE	0x2
+#define CM2_BASE	0x3

+#define BASE_ID_SHIFT	13
+#define MOD_MASK	((1<<  BASE_ID_SHIFT)-1)
+
+#define PRM_BASE_ID		(PRM_BASE<<  BASE_ID_SHIFT)
+#define PRCM_MPU_BASE_ID	(PRCM_MPU_BASE<<  BASE_ID_SHIFT)
+#define CM2_BASE_ID		(CM2_BASE<<  BASE_ID_SHIFT)
+
+/* CM1 instances */
  #define OMAP4430_CM1_OCP_SOCKET_MOD	0x0000
  #define OMAP4430_CM1_CKGEN_MOD		0x0100
  #define OMAP4430_CM1_MPU_MOD		0x0300
@@ -71,19 +87,19 @@

  /* CM2 instances */

-#define OMAP4430_CM2_OCP_SOCKET_MOD	0x0000
-#define OMAP4430_CM2_CKGEN_MOD		0x0100
-#define OMAP4430_CM2_ALWAYS_ON_MOD	0x0600
-#define OMAP4430_CM2_CORE_MOD		0x0700
-#define OMAP4430_CM2_IVAHD_MOD		0x0f00
-#define OMAP4430_CM2_CAM_MOD		0x1000
-#define OMAP4430_CM2_DSS_MOD		0x1100
-#define OMAP4430_CM2_GFX_MOD		0x1200
-#define OMAP4430_CM2_L3INIT_MOD		0x1300
-#define OMAP4430_CM2_L4PER_MOD		0x1400
-#define OMAP4430_CM2_CEFUSE_MOD		0x1600
-#define OMAP4430_CM2_RESTORE_MOD	0x1e00
-#define OMAP4430_CM2_INSTR_MOD		0x1f00
+#define OMAP4430_CM2_OCP_SOCKET_MOD	0x0000 | CM2_BASE_ID
+#define OMAP4430_CM2_CKGEN_MOD		0x0100 | CM2_BASE_ID
+#define OMAP4430_CM2_ALWAYS_ON_MOD	0x0600 | CM2_BASE_ID
+#define OMAP4430_CM2_CORE_MOD		0x0700 | CM2_BASE_ID
+#define OMAP4430_CM2_IVAHD_MOD		0x0f00 | CM2_BASE_ID
+#define OMAP4430_CM2_CAM_MOD		0x1000 | CM2_BASE_ID
+#define OMAP4430_CM2_DSS_MOD		0x1100 | CM2_BASE_ID
+#define OMAP4430_CM2_GFX_MOD		0x1200 | CM2_BASE_ID
+#define OMAP4430_CM2_L3INIT_MOD		0x1300 | CM2_BASE_ID
+#define OMAP4430_CM2_L4PER_MOD		0x1400 | CM2_BASE_ID
+#define OMAP4430_CM2_CEFUSE_MOD		0x1600 | CM2_BASE_ID
+#define OMAP4430_CM2_RESTORE_MOD	0x1e00 | CM2_BASE_ID
+#define OMAP4430_CM2_INSTR_MOD		0x1f00 | CM2_BASE_ID

  /* PRM instances */

@@ -102,9 +118,9 @@
  #define OMAP4430_PRM_L4PER_MOD		0x1400
  #define OMAP4430_PRM_CEFUSE_MOD		0x1600
  #define OMAP4430_PRM_WKUP_MOD		0x1700
-#define OMAP4430_PRM_WKUP_CM_MOD	0x1800
+#define OMAP4430_PRM_WKUP_CM_MOD	0x1800 | PRM_BASE_ID
  #define OMAP4430_PRM_EMU_MOD		0x1900
-#define OMAP4430_PRM_EMU_CM_MOD		0x1a00
+#define OMAP4430_PRM_EMU_CM_MOD		0x1a00 | PRM_BASE_ID
  #define OMAP4430_PRM_DEVICE_MOD		0x1b00
  #define OMAP4430_PRM_INSTR_MOD		0x1f00

@@ -114,10 +130,10 @@

  /* PRCM_MPU instances */

-#define OMAP4430_PRCM_MPU_OCP_SOCKET_PRCM_MOD	0x0000
-#define OMAP4430_PRCM_MPU_DEVICE_PRM_MOD	0x0200
-#define OMAP4430_PRCM_MPU_CPU0_MOD		0x0400
-#define OMAP4430_PRCM_MPU_CPU1_MOD		0x0800
+#define OMAP4430_PRCM_MPU_OCP_SOCKET_PRCM_MOD	0x0000 | PRCM_MPU_BASE_ID
+#define OMAP4430_PRCM_MPU_DEVICE_PRM_MOD	0x0200 | PRCM_MPU_BASE_ID
+#define OMAP4430_PRCM_MPU_CPU0_MOD		0x0400 | PRCM_MPU_BASE_ID
+#define OMAP4430_PRCM_MPU_CPU1_MOD		0x0800 | PRCM_MPU_BASE_ID


  /* 24XX register bits shared between CM&  PRM registers */
diff --git a/arch/arm/mach-omap2/prcm.c b/arch/arm/mach-omap2/prcm.c
index 4df30d0..124e866 100644
--- a/arch/arm/mach-omap2/prcm.c
+++ b/arch/arm/mach-omap2/prcm.c
@@ -182,13 +182,40 @@ static inline void __omap_prcm_write(u32 value, void __iomem *base,
  /* Read a register in a PRM module */
  u32 prm_read_mod_reg(s16 module, u16 idx)
  {
-	return __omap_prcm_read(prm_base, module, idx);
+	u32 base = 0;
+
+	base = abs(module)>>  BASE_ID_SHIFT;
+	module&= MOD_MASK;
+
+	switch (base) {
+	case PRCM_MPU_BASE:
+		return __omap_prcm_read(prcm_mpu_base, module, idx);
+	case DEFAULT_BASE:
+		return __omap_prcm_read(prm_base, module, idx);
+	default:
+		pr_err("Unknown PRM submodule base\n");
+	}
+	return 0;
  }

  /* Write into a register in a PRM module */
  void prm_write_mod_reg(u32 val, s16 module, u16 idx)
  {
-	__omap_prcm_write(val, prm_base, module, idx);
+	u32 base = 0;
+
+	base = abs(module)>>  BASE_ID_SHIFT;
+
+	switch (base) {
+	case PRCM_MPU_BASE:
+		__omap_prcm_write(val, prcm_mpu_base, module, idx);
+		break;
+	case DEFAULT_BASE:
+		__omap_prcm_write(val, prm_base, module, idx);
+		break;
+	default:
+		pr_err("Unknown PRM submodule base\n");
+		break;
+	}
  }

  /* Read-modify-write a register in a PRM module. Caller must lock */
@@ -219,13 +246,46 @@ u32 prm_read_mod_bits_shift(s16 domain, s16 idx, u32 mask)
  /* Read a register in a CM module */
  u32 cm_read_mod_reg(s16 module, u16 idx)
  {
-	return __omap_prcm_read(cm_base, module, idx);
+	u32 base = 0;
+
+	base = abs(module)>>  BASE_ID_SHIFT;
+	module&= MOD_MASK;
+
+	switch (base) {
+	case PRM_BASE:
+		return __omap_prcm_read(prm_base, module, idx);
+	case CM2_BASE:
+		return __omap_prcm_read(cm2_base, module, idx);
+	case DEFAULT_BASE:
+		return __omap_prcm_read(cm_base, module, idx);
+	default:
+		pr_err("Unknown CM submodule base\n");
+	}
+	return 0;
  }

  /* Write into a register in a CM module */
  void cm_write_mod_reg(u32 val, s16 module, u16 idx)
  {
-	__omap_prcm_write(val, cm_base, module, idx);
+	u32 base = 0;
+
+	base = abs(module)>>  BASE_ID_SHIFT;
+	module&= MOD_MASK;
+
+	switch (base) {
+	case PRM_BASE:
+		__omap_prcm_write(val, prm_base, module, idx);
+		break;
+	case CM2_BASE:
+		__omap_prcm_write(val, cm2_base, module, idx);
+		break;
+	case DEFAULT_BASE:
+		__omap_prcm_write(val, cm_base, module, idx);
+		break;
+	default:
+		pr_err("Unknown CM submodule base\n");
+		break;
+	}
  }

  /* Read-modify-write a register in a CM module. Caller must lock */
diff --git a/arch/arm/mach-omap2/prm.h b/arch/arm/mach-omap2/prm.h
index 588873b..72456cc 100644
--- a/arch/arm/mach-omap2/prm.h
+++ b/arch/arm/mach-omap2/prm.h
@@ -23,9 +23,9 @@
  #define OMAP34XX_PRM_REGADDR(module, reg)				\
  		OMAP2_L4_IO_ADDRESS(OMAP3430_PRM_BASE + (module) + (reg))
  #define OMAP44XX_PRM_REGADDR(module, reg)				\
-		OMAP2_L4_IO_ADDRESS(OMAP4430_PRM_BASE + (module) + (reg))
+		OMAP2_L4_IO_ADDRESS(OMAP4430_PRM_BASE +	((module)&  (MOD_MASK)) + (reg))
  #define OMAP44XX_PRCM_MPU_REGADDR(module, reg)				\
-		OMAP2_L4_IO_ADDRESS(OMAP4430_PRCM_MPU_BASE + (module) + (reg))
+		OMAP2_L4_IO_ADDRESS(OMAP4430_PRCM_MPU_BASE + ((module)&  (MOD_MASK)) + (reg))

  #include "prm44xx.h"

--
1.7.0.4

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- Paul

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