Hello Rajendra,
On Tue, 26 Aug 2008, Rajendra Nayak wrote:
> This is an updated set of CPUidle patches for OMAP3 with a few more comment
> fixes, cleanup, 2.6.27-rc3 migration.
Thanks - here are a few more review comments:
Bugs
----
1. In patch 3/6, control.c:omap3_save_scratchpad_contents() calls
get_restore_pointer(). This is defined in sleep34xx.S; its purpose
appears to be to return the SRAM address of the code at the
"restore" label in omap34xx_cpu_suspend(), later in the same file.
Is this summary correct? If so, I don't see how this can
work. The code will initially be loaded into SDRAM space,
so the address of the "restore" label will be an address in SDRAM.
omap34xx_cpu_suspend() will get pushed into SRAM by pm34xx.c during
boot, but the address of the "restore" label will still be in SDRAM
code. To me, it seems that the get_restore_pointer() SRAM code is
unnecessary and should be dropped; and that you should add a
".globl restore" directive in sleep34xx.S to make the label
available to the linker. Is this interpretation correct?
2. In patch 3/6, the memcpys to scratchpad space should use
memcpy_toio().
3. In patch 4/6, the scratchpad reads/writes in restore_table_entry()
should use __raw_writel/__raw_readl.
Optimizations
-------------
4. In patch 1/6, the two pwrdm_lookup() calls should be moved out of
omap3_enter_idle() to keep it fast. Move them to omap3_idle_init(),
and just use file static mpu_pd, core_pd variables.
CodingStyle
-----------
5. In several places in these patches, your comments are missing a
space between the comment text and the comment delimiter */.
Please add a space in on these per CodingStyle. You can use the
following command to find these in your patches/source files:
egrep -n '[^[:space:]]\*/' filename_goes_here
6. In patch 2/6, in omap3_enter_idle() changes, remove second semicolon
here:
+ struct powerdomain *mpu_pd, *core_pd;;
7. In patch 2/6: in the pm34xx.c:omap_sram_idle(), use tabs rather
than spaces for indentation here:
+ set_pwrdm_state(neon_pwrdm, mpu_next_state);
8. In patch 3/6: in control.c:omap3_clear_scratchpad_contents(), this
comment should be changed to follow CodingStyle for multi-line
comments, e.g.:
/*
* Clears the scratchpad contents in case of cold boot -
* called during bootup
*/
rather than:
+/* Clears the scratchpad contents in case of cold boot-
+ called during bootup*/
9. In patch 4/6, most of the comments in restore_table_entry() seem
unnecessary and should be removed. It would be much better to have
a good comment at the top of this function explaining why the MMU
table address needs to be converted from a physical address to a
virtual address. (I assume this is the address of the page table?)
Other
-----
10. In patch 2/6: in pm34xx.c:omap3_pm_init(), the comment beginning with
"REVISIT: This wkdep" should go *between* the two pwrdm_add_wkdep()
statements, rather than before them, since it only applies to the
second pwrdm_add_wkdep().
+ /*
+ * REVISIT: This wkdep is only necessary when GPIO2-6 are enabled for
+ * IO-pad wakeup. Otherwise it will unnecessarily waste power
+ * waking up PER with every CORE wakeup - see
+ * http://marc.info/?l=linux-omap&m=121852150710062&w=2
+ */
+ pwrdm_add_wkdep(neon_pwrdm, mpu_pwrdm);
+ pwrdm_add_wkdep(per_pwrdm, core_pwrdm);
11. Scratchpad is misspelled on patch 3/6: s/SCRATHPAD/SCRATCHPAD/g
+ u32 max_offset = OMAP343X_SCRATHPAD_ROM_OFFSET;
12. In patch 3/6, in control.c:omap3_clear_scratchpad_contents(),
please use:
if (prm_read_mod_reg(OMAP3430_GR_MOD, OMAP3430_PRM_RSTST_OFFSET) &
OMAP3430_GLOBAL_COLD_RST)) {
in place of this:
+ if (__raw_readl(OMAP3430_PRM_RSTST) & 0x1) {
The former uses preprocessor macros rather than "magic numbers," so
is easier to understand; and uses the PRCM accessor functions
rather than __raw_readl.
13. In patch 3/6, in control.c:omap3_clear_scratchpad_contents(),
please use:
prm_set_mod_reg_bits(OMAP3430_GLOBAL_COLD_RST, OMAP3430_GR_MOD,
OMAP3430_PRM_RSTST_OFFSET);
in place of this code:
+ v = __raw_readl(OMAP3430_PRM_RSTST);
+ v |= 0x1;
+ __raw_writel(v, OMAP3430_PRM_RSTST);
14. In patch 3/6, in control.c, please drop the OMAP3430_PRM_RSTST define,
since it now should no longer be necessary.
15. In patch 3/6, in control.c:omap3_save_scratchpad_contents(),
please get rid of the following casts in the public_restore_ptr and
sdrc_context_addr assignments by defining them as (u32 *) in the
scratchpad_contents structure.
+ scratchpad_contents.public_restore_ptr =
+ (u32)((u32 *)virt_to_phys(get_restore_pointer()));
+ sdrc_block_contents.sdrc_context_addr =
+ (u32)((u32 *)io_v2p(context_mem));
16. In patch 3/6 in control.c:restore_table_entry(), scratchpad_address
and address should be void __iomem *, and io_p2v() should be
OMAP2_IO_ADDRESS() per rmk's recent changes:
+ scratchpad_address = (u32 *)io_p2v(OMAP343X_SCRATCHPAD);
+ address = (u32 *) *(scratchpad_address + OMAP343X_TABLE_ADDRESS_OFFSET);
17. In patch 3/6: please add a comment noting that the "/4" works because
all scratchpad data are 32 bits long.
18. In patch 3/6: in control.h, please at least define these macros as
offsets from OMAP343X_CTRL_BASE, e.g., (OMAP343X_CTRL_BASE + 0x860).
Absolute address defines just cause maintenance headaches in the long
run.
+#define OMAP343X_SCRATCHPAD_ROM 0x48002860
+#define OMAP343X_SCRATCHPAD 0x48002910
19. In patch 3/6: the scratchpad sdrc_context_addr field gets a
pointer to u32 context_mem[128], defined in pm34xx.c, with an
extern defined in control.h. Since this array presumably contains
SDRC context data, it belongs in mach-omap2/sdrc.c, not pm34xx.c.
Similarly, please put the prototype in mach-omap2/sdrc.h, not
control.h; and #include mach-omap2/sdrc.h into control.c.
+u32 context_mem[128];
+
+extern u32 context_mem[128];
20. In patch 5/6: The changes to sleep34xx.S in this patch don't look
right. Can you drop them, or write more about the motivation behind
them?
- Paul
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