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[89.212.118.115]) by smtp.gmail.com with ESMTPSA id i24-20020a05640200d800b00463c367024bsm1557754edu.63.2022.11.05.12.46.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 05 Nov 2022 12:46:48 -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 20:46:47 +0100 Message-ID: <4779430.31r3eYUQgx@jernej-laptop> In-Reply-To: <20221105191954.14360-3-samuel@sholland.org> References: <20221105191954.14360-1-samuel@sholland.org> <20221105191954.14360-3-samuel@sholland.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > > Signed-off-by: Samuel Holland > --- > > drivers/bus/sunxi-rsb.c | 23 +++++++++++++++++------ > 1 file changed, 17 insertions(+), 6 deletions(-) > > 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); > /* common code that starts a transfer */ > static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb) > { > + bool timeout; > + u32 status; > + > if (readl(rsb->regs + RSB_CTRL) & RSB_CTRL_START_TRANS) { > dev_dbg(rsb->dev, "RSB transfer still in progress\n"); > return -EBUSY; > @@ -279,8 +282,16 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb) > writel(RSB_CTRL_START_TRANS | RSB_CTRL_GLOBAL_INT_ENB, > rsb->regs + RSB_CTRL); > > - if (!wait_for_completion_io_timeout(&rsb->complete, > - msecs_to_jiffies(100))) { > + if (irqs_disabled()) { > + timeout = readl_poll_timeout_atomic(rsb->regs + RSB_INTS, > + status, status, 10, 100000); 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. Best regards, Jernej > + } else { > + timeout = !wait_for_completion_io_timeout(&rsb- >complete, > + msecs_to_jiffies(100)); > + status = rsb->status; > + } > + > + if (timeout) { > dev_dbg(rsb->dev, "RSB timeout\n"); > > /* abort the transfer */ > @@ -292,18 +303,18 @@ static int _sunxi_rsb_run_xfer(struct sunxi_rsb *rsb) > return -ETIMEDOUT; > } > > - if (rsb->status & RSB_INTS_LOAD_BSY) { > + if (status & RSB_INTS_LOAD_BSY) { > dev_dbg(rsb->dev, "RSB busy\n"); > return -EBUSY; > } > > - 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) { > dev_dbg(rsb->dev, "RSB slave nack\n"); > return -EINVAL; > } > > - if (rsb->status & RSB_INTS_TRANS_ERR_DATA) { > + if (status & RSB_INTS_TRANS_ERR_DATA) { > dev_dbg(rsb->dev, "RSB transfer data error\n"); > return -EIO; > }