From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E7D32C433E9 for ; Mon, 1 Mar 2021 18:09:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B63C46503F for ; Mon, 1 Mar 2021 18:09:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238647AbhCASHw (ORCPT ); Mon, 1 Mar 2021 13:07:52 -0500 Received: from mail.kernel.org ([198.145.29.99]:52452 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237958AbhCASBi (ORCPT ); Mon, 1 Mar 2021 13:01:38 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 38EBC60235; Mon, 1 Mar 2021 17:48:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614620892; bh=zOhZcygCPytha5FFVuGR60KNwc/AHFFeY3OCV9MChCM=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=gwhsVhhfyf/8CO7zT8AbYh5C6Oe8TrpE2Sm8xB0zy24XuSlTvQkYz/zIpjA0Wo/BO GEOyblQXsdaiWnfTogpe59+PuYaAypwc9RmItTSGxz/CM6nx5dqgIC4T6QYaf2RWui IyE4L9osex0trmYL38IkGHM1x8O18BAeBlr4di1Q= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Rayagonda Kokatanur , Ray Jui , Wolfram Sang , Sasha Levin Subject: [PATCH 5.11 317/775] i2c: iproc: handle master read request Date: Mon, 1 Mar 2021 17:08:05 +0100 Message-Id: <20210301161217.284035189@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161201.679371205@linuxfoundation.org> References: <20210301161201.679371205@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Rayagonda Kokatanur [ Upstream commit e21d79778768e4e187b2892d662c6aaa01e1d399 ] Handle single or multi byte master read request with or without repeated start. Fixes: c245d94ed106 ("i2c: iproc: Add multi byte read-write support for slave mode") Signed-off-by: Rayagonda Kokatanur Acked-by: Ray Jui Signed-off-by: Wolfram Sang Signed-off-by: Sasha Levin --- drivers/i2c/busses/i2c-bcm-iproc.c | 215 +++++++++++++++++++++++------ 1 file changed, 170 insertions(+), 45 deletions(-) diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c index 68db2068f38b0..35baca2f62c4e 100644 --- a/drivers/i2c/busses/i2c-bcm-iproc.c +++ b/drivers/i2c/busses/i2c-bcm-iproc.c @@ -159,6 +159,11 @@ #define IE_S_ALL_INTERRUPT_SHIFT 21 #define IE_S_ALL_INTERRUPT_MASK 0x3f +/* + * It takes ~18us to reading 10bytes of data, hence to keep tasklet + * running for less time, max slave read per tasklet is set to 10 bytes. + */ +#define MAX_SLAVE_RX_PER_INT 10 enum i2c_slave_read_status { I2C_SLAVE_RX_FIFO_EMPTY = 0, @@ -205,8 +210,18 @@ struct bcm_iproc_i2c_dev { /* bytes that have been read */ unsigned int rx_bytes; unsigned int thld_bytes; + + bool slave_rx_only; + bool rx_start_rcvd; + bool slave_read_complete; + u32 tx_underrun; + u32 slave_int_mask; + struct tasklet_struct slave_rx_tasklet; }; +/* tasklet to process slave rx data */ +static void slave_rx_tasklet_fn(unsigned long); + /* * Can be expanded in the future if more interrupt status bits are utilized */ @@ -260,6 +275,7 @@ static void bcm_iproc_i2c_slave_init( { u32 val; + iproc_i2c->tx_underrun = 0; if (need_reset) { /* put controller in reset */ val = iproc_i2c_rd_reg(iproc_i2c, CFG_OFFSET); @@ -296,8 +312,11 @@ static void bcm_iproc_i2c_slave_init( /* Enable interrupt register to indicate a valid byte in receive fifo */ val = BIT(IE_S_RX_EVENT_SHIFT); + /* Enable interrupt register to indicate a Master read transaction */ + val |= BIT(IE_S_RD_EVENT_SHIFT); /* Enable interrupt register for the Slave BUSY command */ val |= BIT(IE_S_START_BUSY_SHIFT); + iproc_i2c->slave_int_mask = val; iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val); } @@ -322,76 +341,176 @@ static void bcm_iproc_i2c_check_slave_status( } } -static bool bcm_iproc_i2c_slave_isr(struct bcm_iproc_i2c_dev *iproc_i2c, - u32 status) +static void bcm_iproc_i2c_slave_read(struct bcm_iproc_i2c_dev *iproc_i2c) { + u8 rx_data, rx_status; + u32 rx_bytes = 0; u32 val; - u8 value, rx_status; - /* Slave RX byte receive */ - if (status & BIT(IS_S_RX_EVENT_SHIFT)) { + while (rx_bytes < MAX_SLAVE_RX_PER_INT) { val = iproc_i2c_rd_reg(iproc_i2c, S_RX_OFFSET); rx_status = (val >> S_RX_STATUS_SHIFT) & S_RX_STATUS_MASK; - if (rx_status == I2C_SLAVE_RX_START) { - /* Start of SMBUS for Master write */ - i2c_slave_event(iproc_i2c->slave, - I2C_SLAVE_WRITE_REQUESTED, &value); + rx_data = ((val >> S_RX_DATA_SHIFT) & S_RX_DATA_MASK); - val = iproc_i2c_rd_reg(iproc_i2c, S_RX_OFFSET); - value = (u8)((val >> S_RX_DATA_SHIFT) & S_RX_DATA_MASK); + if (rx_status == I2C_SLAVE_RX_START) { + /* Start of SMBUS Master write */ i2c_slave_event(iproc_i2c->slave, - I2C_SLAVE_WRITE_RECEIVED, &value); - } else if (status & BIT(IS_S_RD_EVENT_SHIFT)) { - /* Start of SMBUS for Master Read */ + I2C_SLAVE_WRITE_REQUESTED, &rx_data); + iproc_i2c->rx_start_rcvd = true; + iproc_i2c->slave_read_complete = false; + } else if (rx_status == I2C_SLAVE_RX_DATA && + iproc_i2c->rx_start_rcvd) { + /* Middle of SMBUS Master write */ i2c_slave_event(iproc_i2c->slave, - I2C_SLAVE_READ_REQUESTED, &value); - iproc_i2c_wr_reg(iproc_i2c, S_TX_OFFSET, value); + I2C_SLAVE_WRITE_RECEIVED, &rx_data); + } else if (rx_status == I2C_SLAVE_RX_END && + iproc_i2c->rx_start_rcvd) { + /* End of SMBUS Master write */ + if (iproc_i2c->slave_rx_only) + i2c_slave_event(iproc_i2c->slave, + I2C_SLAVE_WRITE_RECEIVED, + &rx_data); + + i2c_slave_event(iproc_i2c->slave, I2C_SLAVE_STOP, + &rx_data); + } else if (rx_status == I2C_SLAVE_RX_FIFO_EMPTY) { + iproc_i2c->rx_start_rcvd = false; + iproc_i2c->slave_read_complete = true; + break; + } - val = BIT(S_CMD_START_BUSY_SHIFT); - iproc_i2c_wr_reg(iproc_i2c, S_CMD_OFFSET, val); + rx_bytes++; + } +} - /* - * Enable interrupt for TX FIFO becomes empty and - * less than PKT_LENGTH bytes were output on the SMBUS - */ - val = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET); - val |= BIT(IE_S_TX_UNDERRUN_SHIFT); - iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val); - } else { - /* Master write other than start */ - value = (u8)((val >> S_RX_DATA_SHIFT) & S_RX_DATA_MASK); +static void slave_rx_tasklet_fn(unsigned long data) +{ + struct bcm_iproc_i2c_dev *iproc_i2c = (struct bcm_iproc_i2c_dev *)data; + u32 int_clr; + + bcm_iproc_i2c_slave_read(iproc_i2c); + + /* clear pending IS_S_RX_EVENT_SHIFT interrupt */ + int_clr = BIT(IS_S_RX_EVENT_SHIFT); + + if (!iproc_i2c->slave_rx_only && iproc_i2c->slave_read_complete) { + /* + * In case of single byte master-read request, + * IS_S_TX_UNDERRUN_SHIFT event is generated before + * IS_S_START_BUSY_SHIFT event. Hence start slave data send + * from first IS_S_TX_UNDERRUN_SHIFT event. + * + * This means don't send any data from slave when + * IS_S_RD_EVENT_SHIFT event is generated else it will increment + * eeprom or other backend slave driver read pointer twice. + */ + iproc_i2c->tx_underrun = 0; + iproc_i2c->slave_int_mask |= BIT(IE_S_TX_UNDERRUN_SHIFT); + + /* clear IS_S_RD_EVENT_SHIFT interrupt */ + int_clr |= BIT(IS_S_RD_EVENT_SHIFT); + } + + /* clear slave interrupt */ + iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, int_clr); + /* enable slave interrupts */ + iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, iproc_i2c->slave_int_mask); +} + +static bool bcm_iproc_i2c_slave_isr(struct bcm_iproc_i2c_dev *iproc_i2c, + u32 status) +{ + u32 val; + u8 value; + + /* + * Slave events in case of master-write, master-write-read and, + * master-read + * + * Master-write : only IS_S_RX_EVENT_SHIFT event + * Master-write-read: both IS_S_RX_EVENT_SHIFT and IS_S_RD_EVENT_SHIFT + * events + * Master-read : both IS_S_RX_EVENT_SHIFT and IS_S_RD_EVENT_SHIFT + * events or only IS_S_RD_EVENT_SHIFT + */ + if (status & BIT(IS_S_RX_EVENT_SHIFT) || + status & BIT(IS_S_RD_EVENT_SHIFT)) { + /* disable slave interrupts */ + val = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET); + val &= ~iproc_i2c->slave_int_mask; + iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val); + + if (status & BIT(IS_S_RD_EVENT_SHIFT)) + /* Master-write-read request */ + iproc_i2c->slave_rx_only = false; + else + /* Master-write request only */ + iproc_i2c->slave_rx_only = true; + + /* schedule tasklet to read data later */ + tasklet_schedule(&iproc_i2c->slave_rx_tasklet); + + /* clear only IS_S_RX_EVENT_SHIFT interrupt */ + iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, + BIT(IS_S_RX_EVENT_SHIFT)); + } + + if (status & BIT(IS_S_TX_UNDERRUN_SHIFT)) { + iproc_i2c->tx_underrun++; + if (iproc_i2c->tx_underrun == 1) + /* Start of SMBUS for Master Read */ i2c_slave_event(iproc_i2c->slave, - I2C_SLAVE_WRITE_RECEIVED, &value); - if (rx_status == I2C_SLAVE_RX_END) - i2c_slave_event(iproc_i2c->slave, - I2C_SLAVE_STOP, &value); - } - } else if (status & BIT(IS_S_TX_UNDERRUN_SHIFT)) { - /* Master read other than start */ - i2c_slave_event(iproc_i2c->slave, - I2C_SLAVE_READ_PROCESSED, &value); + I2C_SLAVE_READ_REQUESTED, + &value); + else + /* Master read other than start */ + i2c_slave_event(iproc_i2c->slave, + I2C_SLAVE_READ_PROCESSED, + &value); iproc_i2c_wr_reg(iproc_i2c, S_TX_OFFSET, value); + /* start transfer */ val = BIT(S_CMD_START_BUSY_SHIFT); iproc_i2c_wr_reg(iproc_i2c, S_CMD_OFFSET, val); + + /* clear interrupt */ + iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, + BIT(IS_S_TX_UNDERRUN_SHIFT)); } - /* Stop */ + /* Stop received from master in case of master read transaction */ if (status & BIT(IS_S_START_BUSY_SHIFT)) { - i2c_slave_event(iproc_i2c->slave, I2C_SLAVE_STOP, &value); /* * Enable interrupt for TX FIFO becomes empty and * less than PKT_LENGTH bytes were output on the SMBUS */ - val = iproc_i2c_rd_reg(iproc_i2c, IE_OFFSET); - val &= ~BIT(IE_S_TX_UNDERRUN_SHIFT); - iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, val); + iproc_i2c->slave_int_mask &= ~BIT(IE_S_TX_UNDERRUN_SHIFT); + iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, + iproc_i2c->slave_int_mask); + + /* End of SMBUS for Master Read */ + val = BIT(S_TX_WR_STATUS_SHIFT); + iproc_i2c_wr_reg(iproc_i2c, S_TX_OFFSET, val); + + val = BIT(S_CMD_START_BUSY_SHIFT); + iproc_i2c_wr_reg(iproc_i2c, S_CMD_OFFSET, val); + + /* flush TX FIFOs */ + val = iproc_i2c_rd_reg(iproc_i2c, S_FIFO_CTRL_OFFSET); + val |= (BIT(S_FIFO_TX_FLUSH_SHIFT)); + iproc_i2c_wr_reg(iproc_i2c, S_FIFO_CTRL_OFFSET, val); + + i2c_slave_event(iproc_i2c->slave, I2C_SLAVE_STOP, &value); + + /* clear interrupt */ + iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, + BIT(IS_S_START_BUSY_SHIFT)); } - /* clear interrupt status */ - iproc_i2c_wr_reg(iproc_i2c, IS_OFFSET, status); + /* check slave transmit status only if slave is transmitting */ + if (!iproc_i2c->slave_rx_only) + bcm_iproc_i2c_check_slave_status(iproc_i2c); - bcm_iproc_i2c_check_slave_status(iproc_i2c); return true; } @@ -1072,6 +1191,10 @@ static int bcm_iproc_i2c_reg_slave(struct i2c_client *slave) return -EAFNOSUPPORT; iproc_i2c->slave = slave; + + tasklet_init(&iproc_i2c->slave_rx_tasklet, slave_rx_tasklet_fn, + (unsigned long)iproc_i2c); + bcm_iproc_i2c_slave_init(iproc_i2c, false); return 0; } @@ -1092,6 +1215,8 @@ static int bcm_iproc_i2c_unreg_slave(struct i2c_client *slave) IE_S_ALL_INTERRUPT_SHIFT); iproc_i2c_wr_reg(iproc_i2c, IE_OFFSET, tmp); + tasklet_kill(&iproc_i2c->slave_rx_tasklet); + /* Erase the slave address programmed */ tmp = iproc_i2c_rd_reg(iproc_i2c, S_CFG_SMBUS_ADDR_OFFSET); tmp &= ~BIT(S_CFG_EN_NIC_SMB_ADDR3_SHIFT); -- 2.27.0