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author | Aleksander Morgado <aleksander@aleksander.es> | 2018-09-12 15:45:44 +0200 |
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committer | Sascha Hauer <s.hauer@pengutronix.de> | 2018-09-17 09:50:41 +0200 |
commit | 2d2daa3c65a08c201cbbbad772a93b1855709eb3 (patch) | |
tree | 036960362b7b1f20f058dafc894513b2e5cc714d /common/ratp/i2c.c | |
parent | 742ba2bf084c8d7f6db6af5ce02ebc4d848df013 (diff) | |
download | barebox-2d2daa3c65a08c201cbbbad772a93b1855709eb3.tar.gz barebox-2d2daa3c65a08c201cbbbad772a93b1855709eb3.tar.xz |
ratp: implement i2c read/write support
Introduce two new RATP commands that allow running i2c read/write
operations, very similar in format to the already existing md/mw
RATP commands.
The messages are defined with a fixed 16-bit long register field, but
it will only be treated as a 16-bit address if I2C_FLAG_WIDE_ADDRESS
is set in the message flags field. If this flag is unset, the start
register address is assumed 8-bit long.
If the message includes the I2C_FLAG_MASTER_MODE flag, the start
register field is ignored and a i2c master send/receive operation is
performed.
Signed-off-by: Aleksander Morgado <aleksander@aleksander.es>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'common/ratp/i2c.c')
-rw-r--r-- | common/ratp/i2c.c | 284 |
1 files changed, 284 insertions, 0 deletions
diff --git a/common/ratp/i2c.c b/common/ratp/i2c.c new file mode 100644 index 0000000000..07097c7f4b --- /dev/null +++ b/common/ratp/i2c.c @@ -0,0 +1,284 @@ +/* + * Copyright (c) 2018 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix + * Copyright (c) 2018 Zodiac Inflight Innovations + * + * See file CREDITS for list of people who contributed to this + * project. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 + * as published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + */ + +#define pr_fmt(fmt) "barebox-ratp: i2c: " fmt + +#include <common.h> +#include <ratp_bb.h> +#include <init.h> +#include <driver.h> +#include <malloc.h> +#include <errno.h> +#include <i2c/i2c.h> + +/* NOTE: + * - Fixed-size fields (e.g. integers) are given just after the header. + * - Variable-length fields are stored inside the buffer[] and their position + * within the buffer[] and their size are given as fixed-sized fields after + * the header. + * The message may be extended at any time keeping backwards compatibility, + * as the position of the buffer[] is given by the buffer_offset field. i.e. + * increasing the buffer_offset field we can extend the fixed-sized section + * to add more fields. + */ + +#define I2C_FLAG_WIDE_ADDRESS BIT(0) +#define I2C_FLAG_MASTER_MODE BIT(1) + +struct ratp_bb_i2c_read_request { + struct ratp_bb header; + uint16_t buffer_offset; + uint8_t bus; + uint8_t addr; + uint16_t reg; + uint8_t flags; + uint16_t size; + uint8_t buffer[]; +} __packed; + +struct ratp_bb_i2c_read_response { + struct ratp_bb header; + uint16_t buffer_offset; + uint32_t errno; + uint16_t data_size; + uint16_t data_offset; + uint8_t buffer[]; +} __packed; + +struct ratp_bb_i2c_write_request { + struct ratp_bb header; + uint16_t buffer_offset; + uint8_t bus; + uint8_t addr; + uint16_t reg; + uint8_t flags; + uint16_t data_size; + uint16_t data_offset; + uint8_t buffer[]; +} __packed; + +struct ratp_bb_i2c_write_response { + struct ratp_bb header; + uint16_t buffer_offset; + uint32_t errno; + uint16_t written; + uint8_t buffer[]; +} __packed; + +static int ratp_cmd_i2c_read(const struct ratp_bb *req, int req_len, + struct ratp_bb **rsp, int *rsp_len) +{ + struct ratp_bb_i2c_read_request *i2c_read_req = (struct ratp_bb_i2c_read_request *)req; + struct ratp_bb_i2c_read_response *i2c_read_rsp; + struct i2c_adapter *adapter; + struct i2c_client client; + uint16_t buffer_offset; + int i2c_read_rsp_len; + uint16_t reg; + uint16_t size; + uint32_t wide = 0; + int ret = 0; + + /* At least message header should be valid */ + if (req_len < sizeof(*i2c_read_req)) { + pr_err("read ignored: size mismatch (%d < %zu)\n", + req_len, sizeof(*i2c_read_req)); + ret = -EINVAL; + goto out_rsp; + } + + /* We don't require any buffer here, but just validate buffer position and size */ + buffer_offset = be16_to_cpu(i2c_read_req->buffer_offset); + if (buffer_offset != req_len) { + pr_err("read ignored: invalid buffer offset (%hu != %d)\n", + buffer_offset, req_len); + ret = -EINVAL; + goto out_rsp; + } + + reg = be16_to_cpu(i2c_read_req->reg); + size = be16_to_cpu(i2c_read_req->size); + if (i2c_read_req->flags & I2C_FLAG_WIDE_ADDRESS) + wide = I2C_ADDR_16_BIT; + +out_rsp: + /* Avoid reading anything on error */ + if (ret != 0) + size = 0; + + i2c_read_rsp_len = sizeof(*i2c_read_rsp) + size; + i2c_read_rsp = xzalloc(i2c_read_rsp_len); + i2c_read_rsp->header.type = cpu_to_be16(BB_RATP_TYPE_I2C_READ_RETURN); + i2c_read_rsp->buffer_offset = cpu_to_be16(sizeof(*i2c_read_rsp)); + i2c_read_rsp->data_offset = 0; + + /* Don't read anything on error or if 0 bytes were requested */ + if (size > 0) { + adapter = i2c_get_adapter(i2c_read_req->bus); + if (!adapter) { + pr_err("read ignored: i2c bus %u not found\n", i2c_read_req->bus); + ret = -ENODEV; + goto out; + } + + client.adapter = adapter; + client.addr = i2c_read_req->addr; + + if (i2c_read_req->flags & I2C_FLAG_MASTER_MODE) { + ret = i2c_master_recv(&client, i2c_read_rsp->buffer, size); + } else { + ret = i2c_read_reg(&client, reg | wide, i2c_read_rsp->buffer, size); + } + if (ret != size) { + pr_err("read ignored: not all bytes read (%u < %u)\n", ret, size); + ret = -EIO; + goto out; + } + ret = 0; + } + +out: + if (ret != 0) { + i2c_read_rsp->data_size = 0; + i2c_read_rsp->errno = cpu_to_be32(ret); + i2c_read_rsp_len = sizeof(*i2c_read_rsp); + } else { + i2c_read_rsp->data_size = cpu_to_be16(size); + i2c_read_rsp->errno = 0; + } + + *rsp = (struct ratp_bb *)i2c_read_rsp; + *rsp_len = i2c_read_rsp_len; + + return ret; +} + +BAREBOX_RATP_CMD_START(I2C_READ) + .request_id = BB_RATP_TYPE_I2C_READ, + .response_id = BB_RATP_TYPE_I2C_READ_RETURN, + .cmd = ratp_cmd_i2c_read +BAREBOX_RATP_CMD_END + + +static int ratp_cmd_i2c_write(const struct ratp_bb *req, int req_len, + struct ratp_bb **rsp, int *rsp_len) +{ + struct ratp_bb_i2c_write_request *i2c_write_req = (struct ratp_bb_i2c_write_request *)req; + struct ratp_bb_i2c_write_response *i2c_write_rsp; + struct i2c_adapter *adapter; + struct i2c_client client; + uint8_t *buffer; + uint16_t buffer_offset; + uint16_t buffer_size; + uint16_t reg; + uint16_t data_offset; + uint16_t data_size; + uint32_t wide = 0; + int ret = 0; + int written = 0; + + /* At least message header should be valid */ + if (req_len < sizeof(*i2c_write_req)) { + pr_err("write ignored: size mismatch (%d < %zu)\n", + req_len, sizeof(*i2c_write_req)); + ret = -EINVAL; + goto out; + } + + /* Validate buffer position and size */ + buffer_offset = be16_to_cpu(i2c_write_req->buffer_offset); + if (req_len < buffer_offset) { + pr_err("write ignored: invalid buffer offset (%d < %hu)\n", + req_len, buffer_offset); + ret = -EINVAL; + goto out; + } + buffer_size = req_len - buffer_offset; + buffer = ((uint8_t *)i2c_write_req) + buffer_offset; + + /* Validate data position and size */ + data_offset = be16_to_cpu(i2c_write_req->data_offset); + if (data_offset != 0) { + pr_err("write ignored: invalid data offset\n"); + ret = -EINVAL; + goto out; + } + data_size = be16_to_cpu(i2c_write_req->data_size); + if (!data_size) { + /* Success */ + goto out; + } + + /* Validate buffer size */ + if (buffer_size < data_size) { + pr_err("write ignored: size mismatch (%d < %hu): data not fully given\n", + buffer_size, data_size); + ret = -EINVAL; + goto out; + } + + reg = be16_to_cpu(i2c_write_req->reg); + if (i2c_write_req->flags & I2C_FLAG_WIDE_ADDRESS) + wide = I2C_ADDR_16_BIT; + + adapter = i2c_get_adapter(i2c_write_req->bus); + if (!adapter) { + pr_err("write ignored: i2c bus %u not found\n", i2c_write_req->bus); + ret = -ENODEV; + goto out; + } + + client.adapter = adapter; + client.addr = i2c_write_req->addr; + + if (i2c_write_req->flags & I2C_FLAG_MASTER_MODE) { + written = i2c_master_send(&client, &buffer[data_offset], data_size); + } else { + written = i2c_write_reg(&client, reg | wide, &buffer[data_offset], data_size); + } + + if (written != data_size) { + pr_err("write ignored: not all bytes written (%u < %u)\n", ret, data_size); + ret = -EIO; + goto out; + } + +out: + i2c_write_rsp = xzalloc(sizeof(*i2c_write_rsp)); + i2c_write_rsp->header.type = cpu_to_be16(BB_RATP_TYPE_I2C_WRITE_RETURN); + i2c_write_rsp->buffer_offset = cpu_to_be16(sizeof(*i2c_write_rsp)); /* n/a */ + + if (ret != 0) { + i2c_write_rsp->written = 0; + i2c_write_rsp->errno = cpu_to_be32(ret); + } else { + i2c_write_rsp->written = cpu_to_be16((uint16_t)written); + i2c_write_rsp->errno = 0; + } + + *rsp = (struct ratp_bb *)i2c_write_rsp; + *rsp_len = sizeof(*i2c_write_rsp); + + return ret; +} + +BAREBOX_RATP_CMD_START(I2C_WRITE) + .request_id = BB_RATP_TYPE_I2C_WRITE, + .response_id = BB_RATP_TYPE_I2C_WRITE_RETURN, + .cmd = ratp_cmd_i2c_write +BAREBOX_RATP_CMD_END |