Hi Cédric,
On Tue, 7 Jan 2020 at 21:20, Cédric Le Goater clg@kaod.org wrote:
On 12/30/19 5:19 AM, Simon Glass wrote:
At present the clock driver reads its ofdata in the probe() method. This is not correct although it is often harmless.
However in this case it causes a problem, something like this:
- ast_get_scu() is called (from somewhere) to get the SCI address
- this probes the clock
- first sets up ofdata (which does nothing at present)
- DM marks clock device as active
- DM calls pinctrl
- pinctrl probes and calls ast_get_scu() in ast2500_pinctrl_probe()
- ast_get_scu() probes the clock, but sees it already marked as probed
- ast_get_scu() accesses the clock's private data, with scu as NULL
- DM calls clock probe function ast2500_clk_probe() which reads scu
By putting the read of scu into the correct method, scu is read as part of ofdata setup, and everything is OK.
Note: This problem did not matter until now since DM always probed all parents before reading a child's ofdata. The fact that pinctrl is a child of clock seems to trigger this strange bug.
Did you find it with QEMU ?
Yes that's right.
Signed-off-by: Simon Glass sjg@chromium.org
Reviewed-by: Cédric Le Goater clg@kaod.org
C.
drivers/clk/aspeed/clk_ast2500.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
Applied to u-boot-dm, thanks!