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Sun, 20 Jan 2019 13:41:20 -0800 (PST) Subject: Re: [PATCH v3 1/8] i2c: iproc: I2C read up to 255 bytes support To: Rayagonda Kokatanur , rjui@broadcom.com References: <1547791464-3540-1-git-send-email-rayagonda.kokatanur@broadcom.com> <1547791464-3540-2-git-send-email-rayagonda.kokatanur@broadcom.com> From: Ray Jui Message-ID: Date: Sun, 20 Jan 2019 13:41:14 -0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <1547791464-3540-2-git-send-email-rayagonda.kokatanur@broadcom.com> Content-Language: en-US X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190120_134124_874974_5F2C1F4D X-CRM114-Status: GOOD ( 26.33 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, Shreesha Rajashekar , heikki.krogerus@linux.intel.com, vigneshr@ti.com, ajayg@nvidia.com, wsa@the-dreams.de, rayagonoda.kokatanur@braodcom.com, aaron.wu@analog.com, pierre-yves.mordret@st.com, kramasub@codeaurora.org, linux-i2c@vger.kernel.org, manivannan.sadhasivam@linaro.org, jdelvare@suse.de, f.fainelli@gmail.com, eajames@linux.vnet.ibm.com, shreesha.rajashekar@broadcom.com, bcm-kernel-feedback-list@broadcom.com, geert@linux-m68k.org, devicetree@vger.kernel.org, arnd@arndb.de, robh+dt@kernel.org, ccheng@broadcom.com, andriy.shevchenko@linux.intel.com, mika.westerberg@linux.intel.com, linux-arm-kernel@lists.infradead.org, sbranden@broadcom.com, ard.biesheuvel@linaro.org, linux-kernel@vger.kernel.org, jarkko.nikula@linux.intel.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 1/17/2019 10:04 PM, Rayagonda Kokatanur wrote: > From: Shreesha Rajashekar > > Add support to allow I2C RX transfer up to 255 bytes. > > Signed-off-by: Rayagonda Kokatanur > Signed-off-by: Shreesha Rajashekar > --- > drivers/i2c/busses/i2c-bcm-iproc.c | 98 +++++++++++++++++++++++++++++--------- > 1 file changed, 76 insertions(+), 22 deletions(-) > > diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c > index 4c8c3bc4669c..eb7339a0280e 100644 > --- a/drivers/i2c/busses/i2c-bcm-iproc.c > +++ b/drivers/i2c/busses/i2c-bcm-iproc.c > @@ -80,6 +80,10 @@ > > #define I2C_TIMEOUT_MSEC 50000 > #define M_TX_RX_FIFO_SIZE 64 > +#define M_RX_FIFO_MAX_THLD_VALUE (M_TX_RX_FIFO_SIZE - 1) > + > +#define M_RX_MAX_READ_LEN 255 > +#define M_RX_FIFO_THLD_VALUE 50 > > enum bus_speed_index { > I2C_SPD_100K = 0, > @@ -102,17 +106,41 @@ struct bcm_iproc_i2c_dev { > > /* bytes that have been transferred */ > unsigned int tx_bytes; > + /* bytes that have been read */ > + unsigned int rx_bytes; > + unsigned int thld_bytes; > }; > > /* > * Can be expanded in the future if more interrupt status bits are utilized > */ > -#define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT)) > +#define ISR_MASK (BIT(IS_M_START_BUSY_SHIFT) | BIT(IS_M_TX_UNDERRUN_SHIFT)\ > + | BIT(IS_M_RX_THLD_SHIFT)) > + > +static void bcm_iproc_i2c_read_valid_bytes(struct bcm_iproc_i2c_dev *iproc_i2c) > +{ > + struct i2c_msg *msg = iproc_i2c->msg; > + > + /* Read valid data from RX FIFO */ > + while (iproc_i2c->rx_bytes < msg->len) { > + if (!((readl(iproc_i2c->base + > + M_FIFO_CTRL_OFFSET) >> > + M_FIFO_RX_CNT_SHIFT) & > + M_FIFO_RX_CNT_MASK)) > + break; > + > + msg->buf[iproc_i2c->rx_bytes] = > + (readl(iproc_i2c->base + M_RX_OFFSET) >> > + M_RX_DATA_SHIFT) & M_RX_DATA_MASK; > + iproc_i2c->rx_bytes++; > + } > +} > > static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) > { > struct bcm_iproc_i2c_dev *iproc_i2c = data; > u32 status = readl(iproc_i2c->base + IS_OFFSET); > + u32 tmp; > > status &= ISR_MASK; > > @@ -136,8 +164,6 @@ static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) > > /* mark the last byte */ > if (idx == msg->len - 1) { > - u32 tmp; > - > val |= BIT(M_TX_WR_STATUS_SHIFT); > > /* > @@ -156,6 +182,32 @@ static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) > iproc_i2c->tx_bytes += tx_bytes; > } > > + if (status & BIT(IS_M_RX_THLD_SHIFT)) { > + struct i2c_msg *msg = iproc_i2c->msg; > + u32 bytes_left; > + > + bcm_iproc_i2c_read_valid_bytes(iproc_i2c); > + bytes_left = msg->len - iproc_i2c->rx_bytes; > + if (bytes_left == 0) { > + /* finished reading all data, disable rx thld event */ > + tmp = readl(iproc_i2c->base + IE_OFFSET); > + tmp &= ~BIT(IS_M_RX_THLD_SHIFT); > + writel(tmp, iproc_i2c->base + IE_OFFSET); > + } else if (bytes_left < iproc_i2c->thld_bytes) { > + /* set bytes left as threshold */ > + tmp = readl(iproc_i2c->base + M_FIFO_CTRL_OFFSET); > + tmp &= ~(M_FIFO_RX_THLD_MASK << M_FIFO_RX_THLD_SHIFT); > + tmp |= (bytes_left << M_FIFO_RX_THLD_SHIFT); > + writel(tmp, iproc_i2c->base + M_FIFO_CTRL_OFFSET); > + iproc_i2c->thld_bytes = bytes_left; > + } > + /* > + * bytes_left >= iproc_i2c->thld_bytes, > + * hence no need to change the THRESHOLD SET. > + * It will remain as iproc_i2c->thld_bytes itself > + */ > + } > + > if (status & BIT(IS_M_START_BUSY_SHIFT)) { > iproc_i2c->xfer_is_done = 1; > complete(&iproc_i2c->done); > @@ -253,7 +305,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, > { > int ret, i; > u8 addr; > - u32 val; > + u32 val, tmp, val_intr_en; > unsigned int tx_bytes; > unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MSEC); > > @@ -298,7 +350,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, > * transaction is done, i.e., the internal start_busy bit, transitions > * from 1 to 0. > */ > - val = BIT(IE_M_START_BUSY_SHIFT); > + val_intr_en = BIT(IE_M_START_BUSY_SHIFT); > > /* > * If TX data size is larger than the TX FIFO, need to enable TX > @@ -307,9 +359,7 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, > */ > if (!(msg->flags & I2C_M_RD) && > msg->len > iproc_i2c->tx_bytes) > - val |= BIT(IE_M_TX_UNDERRUN_SHIFT); > - > - writel(val, iproc_i2c->base + IE_OFFSET); > + val_intr_en |= BIT(IE_M_TX_UNDERRUN_SHIFT); > > /* > * Now we can activate the transfer. For a read operation, specify the > @@ -317,11 +367,27 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, > */ > val = BIT(M_CMD_START_BUSY_SHIFT); > if (msg->flags & I2C_M_RD) { > + iproc_i2c->rx_bytes = 0; > + if (msg->len > M_RX_FIFO_MAX_THLD_VALUE) > + iproc_i2c->thld_bytes = M_RX_FIFO_THLD_VALUE; > + else > + iproc_i2c->thld_bytes = msg->len; > + > + /* set threshold value */ > + tmp = readl(iproc_i2c->base + M_FIFO_CTRL_OFFSET); > + tmp &= ~(M_FIFO_RX_THLD_MASK << M_FIFO_RX_THLD_SHIFT); > + tmp |= iproc_i2c->thld_bytes << M_FIFO_RX_THLD_SHIFT; > + writel(tmp, iproc_i2c->base + M_FIFO_CTRL_OFFSET); > + > + /* enable the RX threshold interrupt */ > + val_intr_en |= BIT(IE_M_RX_THLD_SHIFT); > + > val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) | > (msg->len << M_CMD_RD_CNT_SHIFT); > } else { > val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT); > } > + writel(val_intr_en, iproc_i2c->base + IE_OFFSET); > writel(val, iproc_i2c->base + M_CMD_OFFSET); > > time_left = wait_for_completion_timeout(&iproc_i2c->done, time_left); > @@ -353,17 +419,6 @@ static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *iproc_i2c, > return ret; > } > > - /* > - * For a read operation, we now need to load the data from FIFO > - * into the memory buffer > - */ > - if (msg->flags & I2C_M_RD) { > - for (i = 0; i < msg->len; i++) { > - msg->buf[i] = (readl(iproc_i2c->base + M_RX_OFFSET) >> > - M_RX_DATA_SHIFT) & M_RX_DATA_MASK; > - } > - } > - > return 0; > } > > @@ -395,9 +450,8 @@ static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap) > .functionality = bcm_iproc_i2c_functionality, > }; > > -static const struct i2c_adapter_quirks bcm_iproc_i2c_quirks = { > - /* need to reserve one byte in the FIFO for the slave address */ > - .max_read_len = M_TX_RX_FIFO_SIZE - 1, > +static struct i2c_adapter_quirks bcm_iproc_i2c_quirks = { > + .max_read_len = M_RX_MAX_READ_LEN, > }; > > static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *iproc_i2c) > Reviewed-by: Ray Jui _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel