Re: [PATCH v5 09/11] arm: add support for reserved memory defined by device tree

[Josh Cartwright <joshc@codeaurora.org>]

On Thu, Mar 13, 2014 at 01:46:50PM -0700, Kevin Hilman wrote:
> On Fri, Feb 21, 2014 at 4:25 AM, Marek Szyprowski
> <m.szyprowski@samsung.com> wrote:
> > Enable reserved memory initialization from device tree.
> >
> > Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> 
> This patch has hit -next and several legacy (non-DT) boot failures
> were detected and bisected down to this patch.  A quick scan looks
> like there needs to be some sanity checking whether a DT is even
> present.

Hmm.  Yes, the code unconditionally calls of_flat_dt_scan(), which will
gladly touch initial_boot_params, even though it may be uninitialized.
The below patch should allow these boards to boot...

However, I'm wondering if there is a good reason why we don't parse the
/reserved-memory nodes at the right after we parse the /memory nodes as
part of early_init_dt_scan()...

Thanks,
  Josh

--8<--
Subject: [PATCH] drivers: of: only scan for reserved mem when fdt present

Reported-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Josh Cartwright <joshc@codeaurora.org>
---
 drivers/of/fdt.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 510c0d8..501bc83 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -557,6 +557,9 @@ static int __init __fdt_scan_reserved_mem(unsigned long node, const char *uname,
  */
 void __init early_init_fdt_scan_reserved_mem(void)
 {
+	if (!initial_boot_params)
+		return;
+
 	of_scan_flat_dt(__fdt_scan_reserved_mem, NULL);
 	fdt_init_reserved_mem();
 }
-- 
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