On Fri, May 20, 2022 at 09:30:40AM +0800, tien.sung.ang@xxxxxxxxx wrote:
> From: Ang Tien Sung <tien.sung.ang@xxxxxxxxx>
>
> To support the error handling of a truncated bitstream sent.
A blank line here.
> The current AIB CvP firmware is not capable of handling a
> data stream smaller than 4096bytes. The firmware's limitation
So why don't you check the image size on write_init(), and just prevent
the DMA writing at the very beginning?
> causes a hung-up as it's DMA engine waits forever for the
> completion of the instructed 4096bytes.
A blank line here.
> To resolve this design limitation, both firmware and CvP
> driver made several changes. At the CvP driver, we just
> have to ensure that anything lesser than 4096bytes are
> padded with extra bytes. The CvP will then, initiate the
> tear-down by clearing the START_XFER and CVP_CONFIG bits.
The driver pads the data block to 4096 bytes, then why the CvP still
should fail the reprograming?
If the image size is larger than 1 Page but is not aligned to 1 Page,
will the reprogramming still fail?
> We should also check for CVP_ERROR during the CvP completion.
> A send_buf which is always 4096bytes is used to copy the
> data during every transaction.
>
> Signed-off-by: Ang Tien Sung <tien.sung.ang@xxxxxxxxx>
> ---
> changelog v2:
> * Alignment fix parameter 'conf' altera_cvp_send_block
> ---
> drivers/fpga/altera-cvp.c | 24 +++++++++++++++++++-----
> 1 file changed, 19 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/fpga/altera-cvp.c b/drivers/fpga/altera-cvp.c
> index 4ffb9da537d8..5169f9bcd726 100644
> --- a/drivers/fpga/altera-cvp.c
> +++ b/drivers/fpga/altera-cvp.c
> @@ -81,6 +81,7 @@ struct altera_cvp_conf {
> u8 numclks;
> u32 sent_packets;
> u32 vsec_offset;
> + u8 *send_buf;
> const struct cvp_priv *priv;
> };
>
> @@ -453,7 +454,11 @@ static int altera_cvp_write(struct fpga_manager *mgr, const char *buf,
> }
>
> len = min(conf->priv->block_size, remaining);
> - altera_cvp_send_block(conf, data, len);
> + /* Copy the requested host data into the transmit buffer */
> +
This blank line is not needed.
> + memcpy(conf->send_buf, data, len);
Any padding value is OK?
> + altera_cvp_send_block(conf, (const u32 *)conf->send_buf,
> + conf->priv->block_size);
If the len equals block_size, is the copy still needed?
> data += len / sizeof(u32);
> done += len;
> remaining -= len;
> @@ -492,10 +497,13 @@ static int altera_cvp_write_complete(struct fpga_manager *mgr,
> if (ret)
> return ret;
>
> - /* STEP 16 - check CVP_CONFIG_ERROR_LATCHED bit */
> - altera_read_config_dword(conf, VSE_UNCOR_ERR_STATUS, &val);
> - if (val & VSE_UNCOR_ERR_CVP_CFG_ERR) {
> - dev_err(&mgr->dev, "detected CVP_CONFIG_ERROR_LATCHED!\n");
> + /*
> + * STEP 16 - If bitstream error (truncated/miss-matched),
> + * we shall exit here.
> + */
> + ret = altera_read_config_dword(conf, VSE_CVP_STATUS, &val);
> + if (ret || (val & VSE_CVP_STATUS_CFG_ERR)) {
> + dev_err(&mgr->dev, "CVP_CONFIG_ERROR!\n");
So this new error checking covers the previous "latched error" case?
> return -EPROTO;
> }
>
> @@ -661,6 +669,12 @@ static int altera_cvp_probe(struct pci_dev *pdev,
>
> pci_set_drvdata(pdev, mgr);
>
> + /* Allocate the 4096 block size transmit buffer */
> + conf->send_buf = devm_kzalloc(&pdev->dev, conf->priv->block_size, GFP_KERNEL);
If block_size == ALTERA_CVP_V1_SIZE, the copy is still needed?
> + if (!conf->send_buf) {
> + ret = -ENOMEM;
> + goto err_unmap;
> + }
Maybe it is better move the buffer allocation to write_init()
Thanks,
Yilun
> return 0;
>
> err_unmap:
> --
> 2.25.1
