From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Glass Date: Fri, 10 Jan 2020 09:04:07 +1300 Subject: [PATCH 06/19] aspeed: ast2500: Read clock ofdata in the correct method In-Reply-To: References: <20191230041928.74874-1-sjg@chromium.org> <20191229211913.6.I9f208c8708d1b33625601d8034ef08e6305c09d5@changeid> Message-ID: List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: u-boot@lists.denx.de Hi Cédric, On Tue, 7 Jan 2020 at 21:20, Cédric Le Goater 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 > > Reviewed-by: Cédric Le Goater > > C. > > > --- > > > > drivers/clk/aspeed/clk_ast2500.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/clk/aspeed/clk_ast2500.c b/drivers/clk/aspeed/clk_ast2500.c > > index 9249cf9cdf..b3a3f3d4dd 100644 > > --- a/drivers/clk/aspeed/clk_ast2500.c > > +++ b/drivers/clk/aspeed/clk_ast2500.c > > @@ -490,7 +490,7 @@ struct clk_ops ast2500_clk_ops = { > > .enable = ast2500_clk_enable, > > }; > > > > -static int ast2500_clk_probe(struct udevice *dev) > > +static int ast2500_clk_ofdata_to_platdata(struct udevice *dev) > > { > > struct ast2500_clk_priv *priv = dev_get_priv(dev); > > > > @@ -525,5 +525,5 @@ U_BOOT_DRIVER(aspeed_ast2500_scu) = { > > .priv_auto_alloc_size = sizeof(struct ast2500_clk_priv), > > .ops = &ast2500_clk_ops, > > .bind = ast2500_clk_bind, > > - .probe = ast2500_clk_probe, > > + .ofdata_to_platdata = ast2500_clk_ofdata_to_platdata, > > }; > > > Regards, Simon