[PATCHv2 for soc 4/4] arm: socfpga: Add SMP support for actual socfpga harware

[Pavel Machek]

Hi!

> > > > I actually thought about that... but could not think of non-ugly way
> > > > of doing that. I hope dts will normally be "right" for any production
> > > > system...
> > > 
> > > I think a panic is better just for the reason that if someone is
> > > expecting SMP, but missed the warning message, and later finds out that
> > > the secondary core never came up, it would save some debugging time.
> > > 
> > > Since I have to send out a v3 from the 1st patch anyways, let me verify
> > > that I can get the early warning.
> > 
> > The choice is between a panic() at a point where the only way to find
> > out is to throw in printascii() or a working printk, and ending up with
> > an unbootable kernel, vs continuing the boot and having an almost
> > working system which can be logged into and the messages viewed.
> > 
> > If you have an application which relies on the second CPU coming up,
> > why not have it verify that the second CPU came up (it's quite easy
> > to do - there's POSIX standard libc calls to get the number of online
> > CPUs).
> 
> Point taken...thanks Russell.

Well, I don't think we normally check dtbs for validity with
user-helpful error messages, but it is relatively easy in this case.

---cut here---

Continue booting with second core disabled if cpu1-start-addr is not
present in .dtb.

Signed-off-by: Pavel Machek <pavel at denx.de>

diff --git a/arch/arm/mach-socfpga/platsmp.c b/arch/arm/mach-socfpga/platsmp.c
index 81e0da0..90facdd 100644
--- a/arch/arm/mach-socfpga/platsmp.c
+++ b/arch/arm/mach-socfpga/platsmp.c
@@ -82,6 +82,9 @@ static void __init socfpga_smp_init_cpus(void)
 		ncores = 1;
 	}
 #endif
+	if (!cpu1start_addr)
+		ncores = 1;
+
 	for (i = 0; i < ncores; i++)
 		set_cpu_possible(i, true);
 
diff --git a/arch/arm/mach-socfpga/socfpga.c b/arch/arm/mach-socfpga/socfpga.c
index 334c330..c3cd88b 100644
--- a/arch/arm/mach-socfpga/socfpga.c
+++ b/arch/arm/mach-socfpga/socfpga.c
@@ -74,10 +74,9 @@ static void __init socfpga_sysmgr_init(void)
 
 	np = of_find_compatible_node(NULL, NULL, "altr,sys-mgr");
 
-	if (of_property_read_u32(np, "cpu1-start-addr", (u32 *) &cpu1start_addr)) {
-		early_printk("Need cpu1-start-addr in device tree.\n");
-		panic("Need cpu1-start-addr in device tree.\n");
-	}
+	if (of_property_read_u32(np, "cpu1-start-addr", (u32 *) &cpu1start_addr))
+		printk(KERN_ALERT "Need cpu1-start-addr in device tree for SMP operation.\n");
+
 	sys_manager_base_addr = of_iomap(np, 0);
 
 	np = of_find_compatible_node(NULL, NULL, "altr,rst-mgr");

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html