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Message-ID: <20220604154713.GA243326@yilunxu-OptiPlex-7050>
Date: Sat, 4 Jun 2022 23:47:13 +0800
From: Xu Yilun <yilun.xu@...el.com>
To: Ivan Bornyakov <i.bornyakov@...rotek.ru>
Cc: mdf@...nel.org, hao.wu@...el.com, trix@...hat.com,
Conor.Dooley@...rochip.com, robh+dt@...nel.org,
krzysztof.kozlowski+dt@...aro.org, linux-fpga@...r.kernel.org,
devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
system@...rotek.ru
Subject: Re: [PATCH v14 1/3] fpga: fpga-mgr: support bitstream offset in
image buffer
On Tue, May 31, 2022 at 10:23:42PM +0300, Ivan Bornyakov wrote:
> At the moment FPGA manager core loads to the device entire image
> provided to fpga_mgr_load(). But it is not always whole FPGA image
> buffer meant to be written to the device. In particular, .dat formatted
> image for Microchip MPF contains meta info in the header that is not
> meant to be written to the device. This is issue for those low level
> drivers that loads data to the device with write() fpga_manager_ops
> callback, since write() can be called in iterator over scatter-gather
> table, not only linear image buffer. On the other hand, write_sg()
> callback is provided with whole image in scatter-gather form and can
> decide itself which part should be sent to the device.
>
> Add header_size and data_size to the fpga_image_info struct and adjust
> fpga_mgr_write() callers with respect to them.
>
> * info->header_size indicates part at the beginning of image buffer
> that is *not* meant to be written to the device. It is optional and
> can be 0.
>
> * info->data_size is the size of actual bitstream data that *is* meant
> to be written to the device, starting at info->header_size from the
> beginning of image buffer. It is also optional and can be 0, which
> means bitstream data is up to the end of image buffer.
>
> Also add parse_header() callback to fpga_manager_ops, which purpose is
> to set info->header_size and info->data_size. At least
> initial_header_size bytes of image buffer will be passed into
> parse_header() first time. If it is not enough, parse_header() should
> set desired size into info->header_size and return -EAGAIN, then it will
> be called again with greater part of image buffer on the input.
>
> Signed-off-by: Ivan Bornyakov <i.bornyakov@...rotek.ru>
Only one concern left, The XX_PARSE_HEAD state transition is a little messy,
see my comments inline.
> ---
> drivers/fpga/fpga-mgr.c | 176 ++++++++++++++++++++++++++++------
> include/linux/fpga/fpga-mgr.h | 17 +++-
> 2 files changed, 165 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
> index a3595ecc3f79..34473d482c21 100644
> --- a/drivers/fpga/fpga-mgr.c
> +++ b/drivers/fpga/fpga-mgr.c
> @@ -74,6 +74,15 @@ static inline int fpga_mgr_write_complete(struct fpga_manager *mgr,
> return 0;
> }
>
> +static inline int fpga_mgr_parse_header(struct fpga_manager *mgr,
> + struct fpga_image_info *info,
> + const char *buf, size_t count)
> +{
> + if (mgr->mops->parse_header)
> + return mgr->mops->parse_header(mgr, info, buf, count);
> + return 0;
> +}
> +
> static inline int fpga_mgr_write_init(struct fpga_manager *mgr,
> struct fpga_image_info *info,
> const char *buf, size_t count)
> @@ -136,24 +145,57 @@ void fpga_image_info_free(struct fpga_image_info *info)
> EXPORT_SYMBOL_GPL(fpga_image_info_free);
>
> /*
> - * Call the low level driver's write_init function. This will do the
> + * Call the low level driver's parse_header function. This will set
> + * info->header_size and info->data_size. The low level driver gets entire
> + * buffer provided. If it is not enough, driver should set desired size into
> + * info->header_size and return -EAGAIN, then parse_header() will be called
> + * again with greater part of image buffer on the input.
> + */
> +static int fpga_mgr_parse_header_buf(struct fpga_manager *mgr,
> + struct fpga_image_info *info,
> + const char *buf, size_t count)
> +{
> + int ret;
> +
> + mgr->state = FPGA_MGR_STATE_PARSE_HEADER;
> + ret = fpga_mgr_parse_header(mgr, info, buf, count);
> + if (ret && ret != -EAGAIN) {
> + dev_err(&mgr->dev, "Error while parsing FPGA image header\n");
> + mgr->state = FPGA_MGR_STATE_PARSE_HEADER_ERR;
Try not to assign the state again and again, or outside the
xx_parse_header_xxx() function.
If a single function cannot handle all cases, how about having more
functions, like fpga_mgr_parse_header_mapped(),
fpga_mgr_parse_header_sg_first(), fpga_mgr_parse_header_sg(),
and just toggle the state in these functions.
> + }
> +
> + return ret;
> +}
> +
> +/*
> + * Call the low level driver's write_init function. This will do the
> * device-specific things to get the FPGA into the state where it is ready to
> - * receive an FPGA image. The low level driver only gets to see the first
> - * initial_header_size bytes in the buffer.
> + * receive an FPGA image. If info->header_size is defined, the low level
> + * driver gets to see at least first info->header_size bytes in the buffer,
> + * mgr->mops->initial_header_size otherwise. If neither initial_header_size
> + * nor header_size are not set, write_init will not get any bytes of image
> + * buffer.
> */
> static int fpga_mgr_write_init_buf(struct fpga_manager *mgr,
> struct fpga_image_info *info,
> const char *buf, size_t count)
> {
> + size_t header_size;
> int ret;
>
> mgr->state = FPGA_MGR_STATE_WRITE_INIT;
> - if (!mgr->mops->initial_header_size) {
> +
> + if (info->header_size)
> + header_size = info->header_size;
> + else
> + header_size = mgr->mops->initial_header_size;
> +
> + if (header_size > count)
> + ret = -EINVAL;
> + else if (!header_size)
> ret = fpga_mgr_write_init(mgr, info, NULL, 0);
> - } else {
> - count = min(mgr->mops->initial_header_size, count);
> + else
> ret = fpga_mgr_write_init(mgr, info, buf, count);
> - }
>
> if (ret) {
> dev_err(&mgr->dev, "Error preparing FPGA for writing\n");
> @@ -164,16 +206,17 @@ static int fpga_mgr_write_init_buf(struct fpga_manager *mgr,
> return 0;
> }
>
> -static int fpga_mgr_write_init_sg(struct fpga_manager *mgr,
> - struct fpga_image_info *info,
> - struct sg_table *sgt)
> +static int fpga_mgr_prepare_sg(struct fpga_manager *mgr,
> + struct fpga_image_info *info,
> + struct sg_table *sgt)
> {
> struct sg_mapping_iter miter;
> - size_t len;
> - char *buf;
> + size_t header_size, len;
> + char *buf = NULL;
> int ret;
>
> - if (!mgr->mops->initial_header_size)
> + header_size = mgr->mops->initial_header_size;
> + if (!header_size)
> return fpga_mgr_write_init_buf(mgr, info, NULL, 0);
>
> /*
> @@ -182,22 +225,44 @@ static int fpga_mgr_write_init_sg(struct fpga_manager *mgr,
> */
> sg_miter_start(&miter, sgt->sgl, sgt->nents, SG_MITER_FROM_SG);
> if (sg_miter_next(&miter) &&
> - miter.length >= mgr->mops->initial_header_size) {
> - ret = fpga_mgr_write_init_buf(mgr, info, miter.addr,
> - miter.length);
> - sg_miter_stop(&miter);
> - return ret;
> + miter.length >= header_size) {
> + ret = fpga_mgr_parse_header_buf(mgr, info, miter.addr,
> + miter.length);
Maybe fpga_mgr_parse_header_sg_first()
> + /*
> + * If -EAGAIN, more sg buffer is needed, otherwise the flow
> + * would always end up in this branch.
> + */
> + if (ret != -EAGAIN) {
> + if (!ret)
> + ret = fpga_mgr_write_init_buf(mgr, info, miter.addr,
> + miter.length);
> +
> + sg_miter_stop(&miter);
> + return ret;
> + }
> }
> sg_miter_stop(&miter);
>
> /* Otherwise copy the fragments into temporary memory. */
> - buf = kmalloc(mgr->mops->initial_header_size, GFP_KERNEL);
> - if (!buf)
> - return -ENOMEM;
> + do {
> + if (info->header_size)
> + header_size = info->header_size;
> +
> + buf = krealloc(buf, header_size, GFP_KERNEL);
> + if (!buf)
> + return -ENOMEM;
> +
> + len = sg_copy_to_buffer(sgt->sgl, sgt->nents, buf, header_size);
> + if (len != header_size) {
> + kfree(buf);
> + return -EFAULT;
> + }
> +
> + ret = fpga_mgr_parse_header_buf(mgr, info, buf, header_size);
> + } while (ret == -EAGAIN);
Maybe put the operations in fpga_mgr_parse_header_sg().
>
> - len = sg_copy_to_buffer(sgt->sgl, sgt->nents, buf,
> - mgr->mops->initial_header_size);
> - ret = fpga_mgr_write_init_buf(mgr, info, buf, len);
> + if (!ret)
> + ret = fpga_mgr_write_init_buf(mgr, info, buf, header_size);
>
> kfree(buf);
>
> @@ -227,7 +292,7 @@ static int fpga_mgr_buf_load_sg(struct fpga_manager *mgr,
> {
> int ret;
>
> - ret = fpga_mgr_write_init_sg(mgr, info, sgt);
> + ret = fpga_mgr_prepare_sg(mgr, info, sgt);
> if (ret)
> return ret;
>
> @@ -237,11 +302,40 @@ static int fpga_mgr_buf_load_sg(struct fpga_manager *mgr,
> ret = fpga_mgr_write_sg(mgr, sgt);
> } else {
> struct sg_mapping_iter miter;
> + size_t length, data_size;
> + bool last = false;
> + ssize_t count;
> + char *addr;
> +
> + data_size = info->data_size;
> + count = -info->header_size;
>
> sg_miter_start(&miter, sgt->sgl, sgt->nents, SG_MITER_FROM_SG);
> while (sg_miter_next(&miter)) {
> - ret = fpga_mgr_write(mgr, miter.addr, miter.length);
> - if (ret)
> + count += miter.length;
> +
> + /* sg block contains only header, no data */
> + if (count <= 0)
> + continue;
> +
> + if (count < miter.length) {
> + /* sg block contains both header and data */
> + addr = miter.addr + miter.length - count;
> + length = count;
> + } else {
> + /* sg block contains pure data */
> + addr = miter.addr;
> + length = miter.length;
> + }
> +
> + /* truncate last block to data_size, if needed */
> + if (data_size && count > data_size) {
> + length -= count - data_size;
> + last = true;
> + }
> +
> + ret = fpga_mgr_write(mgr, addr, length);
> + if (ret || last)
> break;
> }
> sg_miter_stop(&miter);
> @@ -262,10 +356,34 @@ static int fpga_mgr_buf_load_mapped(struct fpga_manager *mgr,
> {
> int ret;
>
> + ret = fpga_mgr_parse_header_buf(mgr, info, buf, count);
> + if (ret) {
> + if (ret == -EAGAIN) {
> + dev_err(&mgr->dev, "Header outruns FPGA image\n");
> + mgr->state = FPGA_MGR_STATE_PARSE_HEADER_ERR;
> + ret = -EINVAL;
> + }
> +
> + return ret;
> + }
> +
> + if (info->header_size + info->data_size > count) {
> + dev_err(&mgr->dev, "Bitsream data outruns FPGA image\n");
> + mgr->state = FPGA_MGR_STATE_PARSE_HEADER_ERR;
> + return -EINVAL;
> + }
Maybe put the checks in fpga_mgr_parse_header_mapped()
Thanks,
Yilun
> +
> ret = fpga_mgr_write_init_buf(mgr, info, buf, count);
> if (ret)
> return ret;
>
> + if (info->data_size)
> + count = info->data_size;
> + else
> + count -= info->header_size;
> +
> + buf += info->header_size;
> +
> /*
> * Write the FPGA image to the FPGA.
> */
> @@ -424,6 +542,10 @@ static const char * const state_str[] = {
> [FPGA_MGR_STATE_FIRMWARE_REQ] = "firmware request",
> [FPGA_MGR_STATE_FIRMWARE_REQ_ERR] = "firmware request error",
>
> + /* Parse FPGA image header */
> + [FPGA_MGR_STATE_PARSE_HEADER] = "parse header",
> + [FPGA_MGR_STATE_PARSE_HEADER_ERR] = "parse header error",
> +
> /* Preparing FPGA to receive image */
> [FPGA_MGR_STATE_WRITE_INIT] = "write init",
> [FPGA_MGR_STATE_WRITE_INIT_ERR] = "write init error",
> diff --git a/include/linux/fpga/fpga-mgr.h b/include/linux/fpga/fpga-mgr.h
> index 0f9468771bb9..cba8bb7827a5 100644
> --- a/include/linux/fpga/fpga-mgr.h
> +++ b/include/linux/fpga/fpga-mgr.h
> @@ -22,6 +22,8 @@ struct sg_table;
> * @FPGA_MGR_STATE_RESET: FPGA in reset state
> * @FPGA_MGR_STATE_FIRMWARE_REQ: firmware request in progress
> * @FPGA_MGR_STATE_FIRMWARE_REQ_ERR: firmware request failed
> + * @FPGA_MGR_STATE_PARSE_HEADER: parse FPGA image header
> + * @FPGA_MGR_STATE_PARSE_HEADER_ERR: Error during PARSE_HEADER stage
> * @FPGA_MGR_STATE_WRITE_INIT: preparing FPGA for programming
> * @FPGA_MGR_STATE_WRITE_INIT_ERR: Error during WRITE_INIT stage
> * @FPGA_MGR_STATE_WRITE: writing image to FPGA
> @@ -42,6 +44,8 @@ enum fpga_mgr_states {
> FPGA_MGR_STATE_FIRMWARE_REQ_ERR,
>
> /* write sequence: init, write, complete */
> + FPGA_MGR_STATE_PARSE_HEADER,
> + FPGA_MGR_STATE_PARSE_HEADER_ERR,
> FPGA_MGR_STATE_WRITE_INIT,
> FPGA_MGR_STATE_WRITE_INIT_ERR,
> FPGA_MGR_STATE_WRITE,
> @@ -85,6 +89,8 @@ enum fpga_mgr_states {
> * @sgt: scatter/gather table containing FPGA image
> * @buf: contiguous buffer containing FPGA image
> * @count: size of buf
> + * @header_size: offset in image buffer where bitstream data starts
> + * @data_size: size of bitstream. If 0, (count - header_size) will be used.
> * @region_id: id of target region
> * @dev: device that owns this
> * @overlay: Device Tree overlay
> @@ -98,6 +104,8 @@ struct fpga_image_info {
> struct sg_table *sgt;
> const char *buf;
> size_t count;
> + size_t header_size;
> + size_t data_size;
> int region_id;
> struct device *dev;
> #ifdef CONFIG_OF
> @@ -137,9 +145,13 @@ struct fpga_manager_info {
>
> /**
> * struct fpga_manager_ops - ops for low level fpga manager drivers
> - * @initial_header_size: Maximum number of bytes that should be passed into write_init
> + * @initial_header_size: minimum number of bytes that should be passed into
> + * parse_header and write_init.
> * @state: returns an enum value of the FPGA's state
> * @status: returns status of the FPGA, including reconfiguration error code
> + * @parse_header: parse FPGA image header to set info->header_size and
> + * info->data_size. In case the input buffer is not large enough, set
> + * required size to info->header_size and return -EAGAIN.
> * @write_init: prepare the FPGA to receive configuration data
> * @write: write count bytes of configuration data to the FPGA
> * @write_sg: write the scatter list of configuration data to the FPGA
> @@ -155,6 +167,9 @@ struct fpga_manager_ops {
> size_t initial_header_size;
> enum fpga_mgr_states (*state)(struct fpga_manager *mgr);
> u64 (*status)(struct fpga_manager *mgr);
> + int (*parse_header)(struct fpga_manager *mgr,
> + struct fpga_image_info *info,
> + const char *buf, size_t count);
> int (*write_init)(struct fpga_manager *mgr,
> struct fpga_image_info *info,
> const char *buf, size_t count);
> --
> 2.35.1
>
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