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[89.212.118.115]) by smtp.gmail.com with ESMTPSA id fe11-20020a056402390b00b00461b169c02csm1555318edb.91.2022.11.05.12.48.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 05 Nov 2022 12:48:36 -0700 (PDT) From: Jernej =?utf-8?B?xaBrcmFiZWM=?= To: Chen-Yu Tsai , Samuel Holland Cc: Ivaylo Dimitrov , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, Samuel Holland Subject: Re: [PATCH 2/2] bus: sunxi-rsb: Support atomic transfers Date: Sat, 05 Nov 2022 20:48:35 +0100 Message-ID: <4752203.GXAFRqVoOG@jernej-laptop> In-Reply-To: <4779430.31r3eYUQgx@jernej-laptop> References: <20221105191954.14360-1-samuel@sholland.org> <20221105191954.14360-3-samuel@sholland.org> <4779430.31r3eYUQgx@jernej-laptop> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Dne sobota, 05. november 2022 ob 20:46:47 CET je Jernej =C5=A0krabec napisa= l(a): > Dne sobota, 05. november 2022 ob 20:19:53 CET je Samuel Holland napisal(a= ): > > When communicating with a PMIC during system poweroff (pm_power_off()), > > IRQs are disabled and we are in a RCU read-side critical section, so we > > cannot use wait_for_completion_io_timeout(). Instead, poll the status > > register for transfer completion. > >=20 > > Signed-off-by: Samuel Holland Also a fixes tag would be in order here. Best regards, Jernej > > --- > >=20 > > drivers/bus/sunxi-rsb.c | 23 +++++++++++++++++------ > > 1 file changed, 17 insertions(+), 6 deletions(-) > >=20 > > diff --git a/drivers/bus/sunxi-rsb.c b/drivers/bus/sunxi-rsb.c > > index 17343cd75338..0f0e498d4379 100644 > > --- a/drivers/bus/sunxi-rsb.c > > +++ b/drivers/bus/sunxi-rsb.c > > @@ -267,6 +267,9 @@ EXPORT_SYMBOL_GPL(sunxi_rsb_driver_register); > >=20 > > /* common code that starts a transfer */ > > static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb) > > { > >=20 > > + bool timeout; > > + u32 status; > > + > >=20 > > if (readl(rsb->regs + RSB_CTRL) & RSB_CTRL_START_TRANS) { > > =09 > > dev_dbg(rsb->dev, "RSB transfer still in progress\n"); > > return -EBUSY; > >=20 > > @@ -279,8 +282,16 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb *r= sb) > >=20 > > writel(RSB_CTRL_START_TRANS | RSB_CTRL_GLOBAL_INT_ENB, > > =09 > > rsb->regs + RSB_CTRL); > >=20 > > - if (!wait_for_completion_io_timeout(&rsb->complete, > > - >=20 > msecs_to_jiffies(100))) { >=20 > > + if (irqs_disabled()) { > > + timeout =3D readl_poll_timeout_atomic(rsb->regs + >=20 > RSB_INTS, >=20 > > + status, >=20 > status, 10, 100000); >=20 > It would be good to check only for RSB_INTS_LOAD_BSY, RSB_INTS_TRANS_ERR = and > RSB_INTS_TRANS_OVER flags and clear them afterwards. That way we avoid > problems if this path is used outside power off case. >=20 > Best regards, > Jernej >=20 > > + } else { > > + timeout =3D !wait_for_completion_io_timeout(&rsb- > > > >complete, > > > > + >=20 > msecs_to_jiffies(100)); >=20 > > + status =3D rsb->status; > > + } > > + > > + if (timeout) { > >=20 > > dev_dbg(rsb->dev, "RSB timeout\n"); > > =09 > > /* abort the transfer */ > >=20 > > @@ -292,18 +303,18 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb > > *rsb) > >=20 > > return -ETIMEDOUT; > > =09 > > } > >=20 > > - if (rsb->status & RSB_INTS_LOAD_BSY) { > > + if (status & RSB_INTS_LOAD_BSY) { > >=20 > > dev_dbg(rsb->dev, "RSB busy\n"); > > return -EBUSY; > > =09 > > } > >=20 > > - if (rsb->status & RSB_INTS_TRANS_ERR) { > > - if (rsb->status & RSB_INTS_TRANS_ERR_ACK) { > > + if (status & RSB_INTS_TRANS_ERR) { > > + if (status & RSB_INTS_TRANS_ERR_ACK) { > >=20 > > dev_dbg(rsb->dev, "RSB slave nack\n"); > > return -EINVAL; > > =09 > > } > >=20 > > - if (rsb->status & RSB_INTS_TRANS_ERR_DATA) { > > + if (status & RSB_INTS_TRANS_ERR_DATA) { > >=20 > > dev_dbg(rsb->dev, "RSB transfer data >=20 > error\n"); >=20 > > return -EIO; > > =09 > > }