From patchwork Sat Nov 4 20:20:06 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wolfram Sang X-Patchwork-Id: 45323 Received: from vger.kernel.org ([209.132.180.67]) by www.linuxtv.org with esmtp (Exim 4.84_2) (envelope-from ) id 1eB4yC-0001jn-SI; Sat, 04 Nov 2017 20:23:09 +0000 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756513AbdKDUWj (ORCPT + 1 other); Sat, 4 Nov 2017 16:22:39 -0400 Received: from sauhun.de ([88.99.104.3]:44819 "EHLO pokefinder.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751755AbdKDUU1 (ORCPT ); Sat, 4 Nov 2017 16:20:27 -0400 Received: from localhost (p54B33782.dip0.t-ipconnect.de [84.179.55.130]) by pokefinder.org (Postfix) with ESMTPSA id 4EB862C35B8; Sat, 4 Nov 2017 21:20:24 +0100 (CET) From: Wolfram Sang To: linux-i2c@vger.kernel.org Cc: linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-iio@vger.kernel.org, linux-input@vger.kernel.org, linux-media@vger.kernel.org, Mark Brown , Wolfram Sang Subject: [PATCH v6 6/9] i2c: smbus: use DMA safe buffers for emulated SMBus transactions Date: Sat, 4 Nov 2017 21:20:06 +0100 Message-Id: <20171104202009.3818-7-wsa+renesas@sang-engineering.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20171104202009.3818-1-wsa+renesas@sang-engineering.com> References: <20171104202009.3818-1-wsa+renesas@sang-engineering.com> Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org For all block commands, try to allocate a DMA safe buffer and mark it accordingly. Only use the stack, if the buffers cannot be allocated. Signed-off-by: Wolfram Sang Reviewed-by: Jonathan Cameron --- drivers/i2c/i2c-core-smbus.c | 45 ++++++++++++++++++++++++++++++++++++++------ 1 file changed, 39 insertions(+), 6 deletions(-) diff --git a/drivers/i2c/i2c-core-smbus.c b/drivers/i2c/i2c-core-smbus.c index 4bb9927afd0106..931c274fe26809 100644 --- a/drivers/i2c/i2c-core-smbus.c +++ b/drivers/i2c/i2c-core-smbus.c @@ -18,6 +18,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -291,6 +292,22 @@ s32 i2c_smbus_write_i2c_block_data(const struct i2c_client *client, u8 command, } EXPORT_SYMBOL(i2c_smbus_write_i2c_block_data); +static void i2c_smbus_try_get_dmabuf(struct i2c_msg *msg, u8 init_val) +{ + bool is_read = msg->flags & I2C_M_RD; + unsigned char *dma_buf; + + dma_buf = kzalloc(I2C_SMBUS_BLOCK_MAX + (is_read ? 2 : 3), GFP_KERNEL); + if (!dma_buf) + return; + + msg->buf = dma_buf; + msg->flags |= I2C_M_DMA_SAFE; + + if (init_val) + msg->buf[0] = init_val; + +} /* Simulate a SMBus command using the i2c protocol No checking of parameters is done! */ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, @@ -368,6 +385,7 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, msg[1].flags |= I2C_M_RECV_LEN; msg[1].len = 1; /* block length will be added by the underlying bus driver */ + i2c_smbus_try_get_dmabuf(&msg[1], 0); } else { msg[0].len = data->block[0] + 2; if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 2) { @@ -376,8 +394,10 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, data->block[0]); return -EINVAL; } + + i2c_smbus_try_get_dmabuf(&msg[0], command); for (i = 1; i < msg[0].len; i++) - msgbuf0[i] = data->block[i-1]; + msg[0].buf[i] = data->block[i-1]; } break; case I2C_SMBUS_BLOCK_PROC_CALL: @@ -389,16 +409,21 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, data->block[0]); return -EINVAL; } + msg[0].len = data->block[0] + 2; + i2c_smbus_try_get_dmabuf(&msg[0], command); for (i = 1; i < msg[0].len; i++) - msgbuf0[i] = data->block[i-1]; + msg[0].buf[i] = data->block[i-1]; + msg[1].flags |= I2C_M_RECV_LEN; msg[1].len = 1; /* block length will be added by the underlying bus driver */ + i2c_smbus_try_get_dmabuf(&msg[1], 0); break; case I2C_SMBUS_I2C_BLOCK_DATA: if (read_write == I2C_SMBUS_READ) { msg[1].len = data->block[0]; + i2c_smbus_try_get_dmabuf(&msg[1], 0); } else { msg[0].len = data->block[0] + 1; if (msg[0].len > I2C_SMBUS_BLOCK_MAX + 1) { @@ -407,8 +432,10 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, data->block[0]); return -EINVAL; } + + i2c_smbus_try_get_dmabuf(&msg[0], command); for (i = 1; i <= data->block[0]; i++) - msgbuf0[i] = data->block[i]; + msg[0].buf[i] = data->block[i]; } break; default: @@ -456,14 +483,20 @@ static s32 i2c_smbus_xfer_emulated(struct i2c_adapter *adapter, u16 addr, break; case I2C_SMBUS_I2C_BLOCK_DATA: for (i = 0; i < data->block[0]; i++) - data->block[i+1] = msgbuf1[i]; + data->block[i+1] = msg[1].buf[i]; break; case I2C_SMBUS_BLOCK_DATA: case I2C_SMBUS_BLOCK_PROC_CALL: - for (i = 0; i < msgbuf1[0] + 1; i++) - data->block[i] = msgbuf1[i]; + for (i = 0; i < msg[1].buf[0] + 1; i++) + data->block[i] = msg[1].buf[i]; break; } + + if (msg[0].flags & I2C_M_DMA_SAFE) + kfree(msg[0].buf); + if (msg[1].flags & I2C_M_DMA_SAFE) + kfree(msg[1].buf); + return 0; }