On Thu, 2014-02-13 at 01:05 -0600, Tang Yuantian-B29983 wrote:
Thanks for your review. Please see the reply inline.
Thanks, Yuantian
-----Original Message----- From: Wood Scott-B07421 Sent: 2014年2月13日 星期四 8:44 To: Tang Yuantian-B29983 Cc: Sun York-R58495; Wood Scott-B07421; Li Yang-Leo-R58472; Tang@theia.denx.de; u-boot@lists.denx.de; Kushwaha Prabhakar-B32579; Jin Zhengxiong-R64188 Subject: Re: [U-Boot,2/3] mpc85xx: Add deep sleep framework support
On Sun, Jan 26, 2014 at 02:00:40PM +0800, tang yuantian wrote:
From: Tang Yuantian yuantian.tang@freescale.com
When system wakes up from warm reset, control is passed to the primary core that starts executing uboot. After re-initialized some IP blocks, like DDRC, kernel will take responsibility to continue to restore environment it leaves before.
Signed-off-by: Tang Yuantian Yuantian.Tang@freescale.com
Is this for some specific mpc85xx chip (e.g. T1040)? I'm pretty sure this isn't necessary for deep sleep on mpc8536, for example.
Currently, it is used by t1040. But we want it to be more general so that It can be used by later new chips.
But the mechanism is not the same for all mpc85xx derivatives. You'll need a more specific name.
+#ifdef CONFIG_DEEP_SLEEP
CONFIG symbols need to be documented in README...
Where should I add this README?
Under "85xx CPU Options" in the top-level README.
- /* disable the console if boot from warm reset */
- if (in_be32(&gur->scrtsr[0]) & (1 << 3))
gd->flags |=GD_FLG_SILENT | GD_FLG_WARM_BOOT |GD_FLG_DISABLE_CONSOLE; #endif
...and it should probably be a more specific CONFIG_SYS symbol that indicates the presence of this guts bit.
diff --git a/arch/powerpc/cpu/mpc85xx/fdt.c b/arch/powerpc/cpu/mpc85xx/fdt.c index 33bc900..b3b9250 100644 --- a/arch/powerpc/cpu/mpc85xx/fdt.c +++ b/arch/powerpc/cpu/mpc85xx/fdt.c @@ -24,6 +24,9 @@ DECLARE_GLOBAL_DATA_PTR; extern void ft_qe_setup(void *blob); extern void ft_fixup_num_cores(void *blob); extern void ft_srio_setup(void *blob); +#ifdef CONFIG_DEEP_SLEEP +extern ulong __bss_end; +#endif
Don't ifdef declarations.
#ifdef CONFIG_MP #include "mp.h" @@ -35,6 +38,9 @@ void ft_fixup_cpu(void *blob, u64 memory_limit) u32 bootpg = determine_mp_bootpg(NULL); u32 id = get_my_id(); const char *enable_method; +#ifdef CONFIG_DEEP_SLEEP
- ulong len;
+#endif
off = fdt_node_offset_by_prop_value(blob, -1, "device_type", "cpu",
4);
while (off != -FDT_ERR_NOTFOUND) { @@ -77,6 +83,25 @@ void ft_fixup_cpu(void *blob, u64 memory_limit) "device_type", "cpu", 4); }
+#ifdef CONFIG_DEEP_SLEEP
- /*
* reserve the memory space for warm reset.* This space will be re-used next time when boot from deep sleep.* The space includes bd_t, gd_t, stack and uboot image.* Reserve 1K for stack.*/- len = sizeof(bd_t) + sizeof(gd_t) + (1 << 10);
- /* round up to 4K */
- len = (len + (4096 - 1)) & ~(4096 - 1);
- off = fdt_add_mem_rsv(blob, gd->relocaddr - len,
len + ((ulong)&__bss_end - gd->relocaddr));- if (off < 0)
printf("Failed to reserve memory for warm reset: %s\n",fdt_strerror(off));+#endif
Why do you need to reserve memory for this? We didn't need to for deep sleep on MPC8313ERDB, which also goes through U-Boot on wake. On MPC8313ERDB we transfer control to the kernel before relocating, so U- Boot never touches DDR. bd_t, gd_t, and the stack should be in locked L1 cache, and the u-boot image should be in flash (or locked CPC if this is not a NOR flash boot).
In deep sleep many IP blocks are powered off like DDRC, LIODN, cpu. These IPs are re-initialized after relocating. So, we must jump to kernel after relocating.
The DDR controller is initialized before relocating -- and of course the CPU is powered off on MPC8313ERDB deep sleep as well.
LIODNs are a new concern for deep sleep, but that doesn't mean we should go through a bunch of unrelated code to get there. Refactor the LIODN code to be usable before relocation, and not be tied to fdt fixups.
+#ifndef CONFIG_DEEP_SLEEP /* Reserve spin table page */ if (spin_tbl_addr < memory_limit) { off = fdt_add_mem_rsv(blob, @@ -108,6 +134,7 @@ void ft_fixup_cpu(void *blob, u64 memory_limit) printf("Failed to reserve memory for spin table: %s\n", fdt_strerror(off)); } +#endif
Explain.
Spin_tbl_addr has been reserved already.
Where, and why is it different for non-CONFIG_DEEP_SLEEP?
#if (CONFIG_SYS_NUM_FMAN == 2)
- set_liodn(fman2_liodn_tbl, fman2_liodn_tbl_sz);
- setup_fman_liodn_base(FSL_HW_PORTAL_FMAN2, fman2_liodn_tbl,
fman2_liodn_tbl_sz);+#ifdef CONFIG_DEEP_SLEEP
- if ((gd->flags & GD_FLG_WARM_BOOT) == 0) {
set_liodn(fman2_liodn_tbl, fman2_liodn_tbl_sz);setup_fman_liodn_base(FSL_HW_PORTAL_FMAN2, fman2_liodn_tbl,fman2_liodn_tbl_sz);- }
+#endif #endif #endif
Aren't you breaking non-CONFIG_DEEP_SLEEP here?
No, if deep sleep feature is enabled, we need to further judge whether this boot is Coming from deep sleep by GD_FLG_WARM_BOOT flag.
My point is that if CONFIG_DEEP_SLEEP is not set, you will be skipping those calls to set_liodn() and setup_fman_liodn_base().
#ifdef foo if (!bar) stuff(); #endif
is not equivalent to:
#ifdef foo if (!bar) #endif stuff();
Though the latter is better written as something like:
bool do_stuff = true;
#ifdef foo if (bar) do_stuff = false; #endif
if (do_stuff) stuff();
or
static inline bool is_bar(void) { #ifdef foo return bar; #else return true; #endif }
...
if (!is_bar()) stuff();
diff --git a/arch/powerpc/include/asm/global_data.h b/arch/powerpc/include/asm/global_data.h index 8e59e8b..1ab05ff 100644 --- a/arch/powerpc/include/asm/global_data.h +++ b/arch/powerpc/include/asm/global_data.h @@ -117,6 +117,7 @@ struct arch_global_data { #include <asm-generic/global_data.h>
#if 1 +#define GD_FLG_WARM_BOOT 0x10000
Why is this not with the rest of the GD_FLGs, not numerically contiguous, and not commented? What specifically does "warm boot" mean? I think a lot of people would expect it to mean something that looks like a reset at the software level, while possibly not involving a real hardware reset -- coming out of deep sleep is the opposite of that.
Archdef document says it is a warm reset boot. So I name it this way.
Hardware people sometimes use terminology differently than software people.
Other platforms use the same flag, like x86, although I am not sure Whether it is for deep sleep. If you have better name, I love to use it.
It's not yet clear to me that a GD flag is needed for this.
#define DECLARE_GLOBAL_DATA_PTR register volatile gd_t *gd asm
("r2")
#else /* We could use plain global data, but the resulting code is
bigger */
#define XTRN_DECLARE_GLOBAL_DATA_PTR extern diff --git a/arch/powerpc/lib/board.c b/arch/powerpc/lib/board.c index 34bbfca..7383e32 100644 --- a/arch/powerpc/lib/board.c +++ b/arch/powerpc/lib/board.c @@ -350,6 +350,13 @@ unsigned long logbuffer_base(void) } #endif
+#ifdef CONFIG_DEEP_SLEEP +int check_warmboot(void) +{
- return !!(gd->flags & GD_FLG_WARM_BOOT); } #endif
Why?
Why what? Why we need it?
It is a help function and used by ASM code in which we can't determine whether it is a warm reset boot.
Why don't you just open code it?
Again, you seem to be breaking the non-CONFIG_DEEP_SLEEP case.
No.
Yes. :-)
+#ifdef CONFIG_DEEP_SLEEP
- /*
* restore 128-byte memory space which corrupted* by DDRC training.*/- if (gd->flags & GD_FLG_WARM_BOOT) {
src = (u64 *)in_be32(&scfg->sparecr[2]);dst = (u64 *)(0);for (i = 0; i < 128/sizeof(u64); i++) {*dst = *src;dst++;src++;}- }
(u64 *)(0) is a NULL pointer. Dereferencing NULL pointers is undefined and GCC has been getting increasingly free with making surprising optimizations based on that (such as assuming any code path that it knows can reach a NULL dereference is dead code and can be removed).
Then how we operate 0 address if not dereferencing NULL pointer?
With an I/O accessor (or other inline asm), a TLB mapping, or using a different memory location.
-Scott