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[109.252.170.211]) by smtp.gmail.com with ESMTPSA id e17sm1677763ljn.18.2020.09.05.13.42.25 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 05 Sep 2020 13:42:25 -0700 (PDT) From: Dmitry Osipenko To: Thierry Reding , Jonathan Hunter , Laxman Dewangan , Wolfram Sang , =?UTF-8?q?Micha=C5=82=20Miros=C5=82aw?= , Andy Shevchenko Cc: linux-i2c@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 01/31] i2c: tegra: Make tegra_i2c_flush_fifos() usable in atomic transfer Date: Sat, 5 Sep 2020 23:41:21 +0300 Message-Id: <20200905204151.25343-2-digetx@gmail.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200905204151.25343-1-digetx@gmail.com> References: <20200905204151.25343-1-digetx@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The tegra_i2c_flush_fifos() shouldn't sleep in atomic transfer and jiffies are not updating if interrupts are disabled. Let's switch to use iopoll API helpers for register-polling. The iopoll API provides helpers for both atomic and non-atomic cases. Note that this patch doesn't fix any known problem because normally FIFO is flushed at the time of starting a new transfer. Signed-off-by: Dmitry Osipenko --- drivers/i2c/busses/i2c-tegra.c | 25 ++++++++++++++++--------- 1 file changed, 16 insertions(+), 9 deletions(-) diff --git a/drivers/i2c/busses/i2c-tegra.c b/drivers/i2c/busses/i2c-tegra.c index 00d3e4d7a01e..ab88cdd70376 100644 --- a/drivers/i2c/busses/i2c-tegra.c +++ b/drivers/i2c/busses/i2c-tegra.c @@ -470,9 +470,9 @@ static int tegra_i2c_init_dma(struct tegra_i2c_dev *i2c_dev) static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev) { - unsigned long timeout = jiffies + HZ; - unsigned int offset; - u32 mask, val; + u32 mask, val, offset, reg_offset; + void __iomem *addr; + int err; if (i2c_dev->hw->has_mst_fifo) { mask = I2C_MST_FIFO_CONTROL_TX_FLUSH | @@ -488,12 +488,19 @@ static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev) val |= mask; i2c_writel(i2c_dev, val, offset); - while (i2c_readl(i2c_dev, offset) & mask) { - if (time_after(jiffies, timeout)) { - dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n"); - return -ETIMEDOUT; - } - usleep_range(1000, 2000); + reg_offset = tegra_i2c_reg_addr(i2c_dev, offset); + addr = i2c_dev->base + reg_offset; + + if (i2c_dev->is_curr_atomic_xfer) + err = readl_relaxed_poll_timeout_atomic(addr, val, !(val & mask), + 1000, 1000000); + else + err = readl_relaxed_poll_timeout(addr, val, !(val & mask), + 1000, 1000000); + + if (err) { + dev_err(i2c_dev->dev, "failed to flush FIFO\n"); + return err; } return 0; } -- 2.27.0