Tony Lindgren had written, on 10/09/2009 01:03 PM, the following:
* Aguirre Rodriguez, Sergio Alberto <[email protected]> [091009 08:59]:
-----Original Message-----
From: Menon, Nishanth Sent: Friday, October 09, 2009 10:56 AM
To: linux-omap
Cc: Menon, Nishanth; Chikkature Rajashekar, Madhusudhan; Pandita, Vikram; Pais, Allen; Gadiyar, Anand; Cousson, Benoit; Felipe Balbi; Kevin Hilman; Premi, Sanjeev; Shilimkar, Santosh; Aguirre Rodriguez, Sergio Alberto; Tony Lindgren
Subject: [PATCH v4] OMAP3: introduce OMAP3630

**--- SNIP ME --
Hi,
A bit of history for this patchset
V4 - Sergio's improvement to the handling of rev decision as we just
     change the define to 3630 and remove crapy override logic in
     omap3_check_revision from v3 patch
Now looks much better ;)

V3 - Fixes from Sergio's comments + boot tested on SDP3430+3630.
V2 - fixes of generic comments from Felipe Balbi+minor cleanups
V1 - inital implementation of (a) approach
V0 - original approach introducing a new silicon family
**--- END OF SNIP ME --
Device intro:
OMAP3630 is the latest in the family of OMAP3 devices
and among the changes it introduces are:

New OPP levels for new voltage and frequency levels. a bunch of
Bug fixes to various modules feature additions, notably with ISP,
sDMA etc.

Details about the chip is available here:
http://focus.ti.com/general/docs/wtbu/wtbuproductcontent.tsp?t
emplateId=6123&navigationId=12836&contentId=52606

Strategy used:
Strategy to introduce this device into Linux was discussed here:
Ref: http://marc.info/?t=125343303400003&r=1&w=2

Two approaches were available:
a) Consider 3630 generation of devices as a new family of silicon
b) Consider 3630 as an offshoot of 3430 family of devices

As a common consensus, (b) seems to be more valid for 3630 as:
* There are changes which are easily handled by using "FEATURES"
  infrastructure.
  For details how to do this, see thread:
  http://marc.info/?t=125050998500001&r=1&w=2
* Most of existing 34xx infrastructure can be reused(almost 90%+)
        - so no ugly if (cpu_is_omap34xx() || cpu_is_omap36xx())
          all over the place
        - lesser chance of bugs due to reuse of proven code flow
        - 36xx specific handling can still be done where required
          within the existing infrastructure

NOTE:
* If additional 34xx series are added, OMAP3430_REV_ESXXXX can be
  added on top of the existing 3630 ones are renumbered

This patch was tested on SDP3430, boot tested on 3630 platform using
3430sdp defconfig

Signed-off-by: Madhusudhan Chikkature Rajashekar <[email protected]>
Signed-off-by: Nishanth Menon <[email protected]>
Signed-off-by: Vikram Pandita <[email protected]>
Cc: Allen Pais <[email protected]>
Cc: Anand Gadiyar <[email protected]>
Cc: Benoit Cousson <[email protected]>
Cc: Felipe Balbi <[email protected]>
Cc: Kevin Hilman <[email protected]>
Cc: Sanjeev Premi <[email protected]>
Cc: Santosh Shilimkar <[email protected]>
Cc: Sergio Alberto Aguirre Rodriguez <[email protected]>
Cc: Tony Lindgren <[email protected]>
Acked-by: Sergio Aguirre <[email protected]>

---
 arch/arm/mach-omap2/id.c              |   24 ++++++++++++++++++++++--
 arch/arm/plat-omap/include/mach/cpu.h |    6 ++++++
 2 files changed, 28 insertions(+), 2 deletions(-)

diff --git a/arch/arm/mach-omap2/id.c b/arch/arm/mach-omap2/id.c
index 03b80f2..ee3bb69 100644
--- a/arch/arm/mach-omap2/id.c
+++ b/arch/arm/mach-omap2/id.c
@@ -210,7 +210,9 @@ void __init omap3_check_revision(void)
        hawkeye = (idcode >> 12) & 0xffff;
        rev = (idcode >> 28) & 0xff;
- if (hawkeye == 0xb7ae) {
+       switch (hawkeye) {
+       case 0xb7ae:
+               /* Handle 34xx devices */
                switch (rev) {
                case 0:
                        omap_revision = OMAP3430_REV_ES2_0;
@@ -231,8 +233,26 @@ void __init omap3_check_revision(void)
                default:
                        /* Use the latest known revision as default */
                        omap_revision = OMAP3430_REV_ES3_1;
-                       rev_name = "Unknown revision\n";
+                       rev_name = "Unknown 34xx revision\n";
                }
+               break;
+       case 0xb891:
+               /* Handle 36xx devices */
+               switch (rev) {
+               case 0:
+                       omap_revision = OMAP3630_REV_ES1_0;
+                       rev_name = "ES1.0";
+                       break;
+               default:
+                       /* Use the latest known revision as default */
+                       omap_revision = OMAP3630_REV_ES1_0;
+                       rev_name = "Unknown 36xx revision\n";
+               }
+               break;
+       default:
+               /* Unknown default to latest rev as default*/
+               omap_revision = OMAP3630_REV_ES1_0;
+               rev_name = "Unknown revision\n";
        }
out: diff --git a/arch/arm/plat-omap/include/mach/cpu.h b/arch/arm/plat-omap/include/mach/cpu.h
index 431fec4..65f1882 100644
--- a/arch/arm/plat-omap/include/mach/cpu.h
+++ b/arch/arm/plat-omap/include/mach/cpu.h
@@ -383,6 +383,12 @@ IS_OMAP_TYPE(3430, 0x3430)
 #define OMAP3430_REV_ES2_1     0x34302034
 #define OMAP3430_REV_ES3_0     0x34303034
 #define OMAP3430_REV_ES3_1     0x34304034
+/* NOTE: Add 36xx series below
+ * If additional 34xx series are added, OMAP3430_REV_ESXXXX can be
+ * added above the 3630 defines and series renumbered to ensure
+ * rev() > checks to work
+ */
+#define OMAP3630_REV_ES1_0     0x36301034

Hmm, to me it looks that this breaks cpu_is_omap34xx() for 36xx, right?

How about build a kernel that boots both on 3430sdp and on some
36xx board and make sure things get detected properly by adding
some debug printk statements?
Tested with the following patch:
diff --git a/arch/arm/mach-omap2/board-3430sdp.c b/arch/arm/mach-omap2/board-3430sdp.c
index 81aabac..2aac26d 100644
--- a/arch/arm/mach-omap2/board-3430sdp.c
+++ b/arch/arm/mach-omap2/board-3430sdp.c
@@ -498,6 +498,8 @@ static struct ehci_hcd_omap_platform_data ehci_pdata __initconst = {

 static void __init omap_3430sdp_init(void)
 {
+       if (cpu_is_omap34xx())
+               printk(KERN_ERR "_______________------ 34xx detected\n");
        omap3430_i2c_init();
        platform_add_devices(sdp3430_devices, ARRAY_SIZE(sdp3430_devices));
        if (omap_rev() > OMAP3430_REV_ES1_0)


and yes, it prints on both 3430 and 3630 platforms (i am hacking at the moment by using 3430sdpdefconfig for both platforms).

Here is why it works:
arch/arm/plat-omap/include/mach/cpu.h
cpu_is_omap343x() depends on is_omap34xx() depends on GET_OMAP_CLASS depends on lower 8 bits of value returned by omap_rev() omap_rev()(arch/arm/mach-omap2/id.c) returns omap_revision. this means omap_rev() will return 0x36301034 -> so class is 0x34.. causing cpu_is_omap343x to be true on 3630 also.

we might want to consider a follow on patch replacing 0x34 with 0x30 and changing cpu_is_omap343x with cpu_is_omap3xxx -> at a later point ofcourse.


--
Regards,
Nishanth Menon
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