[10/11] staging: ralink-gdma: stop using slave_id config

From: Arnd Bergmann <arnd@arndb.de>

Picking the connection between a DMA controller and its attached device
is done through devicetree using the "dmas" property, which is implemented
by the gdma driver, but it also allows overriding the "req" configuration
with the slave_id field, as it was done in some linux-2.6 era drivers.

There is no driver in the tree that sets these values, so stop
interpreting them before anything accidentally starts relying on it.
Rename the field in the channel from "slave_id" to "req" to better match
the purpose and the naming in the hardware.

If any driver actually starts using this DMA engine, it may be necessary
to implement a .xlate callback that sets this field at probe time.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/staging/ralink-gdma/ralink-gdma.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

Hi Arnd,

On Mon, Nov 15, 2021 at 9:55 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> Picking the connection between a DMA controller and its attached device
> is done through devicetree using the "dmas" property, which is implemented
> by the gdma driver, but it also allows overriding the "req" configuration
> with the slave_id field, as it was done in some linux-2.6 era drivers.
>
> There is no driver in the tree that sets these values, so stop
> interpreting them before anything accidentally starts relying on it.
> Rename the field in the channel from "slave_id" to "req" to better match
> the purpose and the naming in the hardware.
>
> If any driver actually starts using this DMA engine, it may be necessary
> to implement a .xlate callback that sets this field at probe time.
>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>  drivers/staging/ralink-gdma/ralink-gdma.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)

This driver has been already deleted from the staging tree. See [0].

Best regards,
    Sergio Paracuellos

[0]: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git/commit/?h=staging-testing&id=5bfc10690c6c590a972be014ed8595e77e1e2dea

>
> diff --git a/drivers/staging/ralink-gdma/ralink-gdma.c b/drivers/staging/ralink-gdma/ralink-gdma.c
> index b5229bc6eae5..f00240e62e1b 100644
> --- a/drivers/staging/ralink-gdma/ralink-gdma.c
> +++ b/drivers/staging/ralink-gdma/ralink-gdma.c
> @@ -106,7 +106,7 @@ struct gdma_dma_desc {
>  struct gdma_dmaengine_chan {
>         struct virt_dma_chan vchan;
>         unsigned int id;
> -       unsigned int slave_id;
> +       unsigned int req;
>
>         dma_addr_t fifo_addr;
>         enum gdma_dma_transfer_size burst_size;
> @@ -194,7 +194,6 @@ static int gdma_dma_config(struct dma_chan *c,
>                         dev_err(dma_dev->ddev.dev, "only support 4 byte buswidth\n");
>                         return -EINVAL;
>                 }
> -               chan->slave_id = config->slave_id;
>                 chan->fifo_addr = config->dst_addr;
>                 chan->burst_size = gdma_dma_maxburst(config->dst_maxburst);
>                 break;
> @@ -203,7 +202,6 @@ static int gdma_dma_config(struct dma_chan *c,
>                         dev_err(dma_dev->ddev.dev, "only support 4 byte buswidth\n");
>                         return -EINVAL;
>                 }
> -               chan->slave_id = config->slave_id;
>                 chan->fifo_addr = config->src_addr;
>                 chan->burst_size = gdma_dma_maxburst(config->src_maxburst);
>                 break;
> @@ -288,12 +286,12 @@ static int rt305x_gdma_start_transfer(struct gdma_dmaengine_chan *chan)
>                 dst_addr = chan->fifo_addr;
>                 ctrl0 = GDMA_REG_CTRL0_DST_ADDR_FIXED |
>                         (8 << GDMA_RT305X_CTRL0_SRC_REQ_SHIFT) |
> -                       (chan->slave_id << GDMA_RT305X_CTRL0_DST_REQ_SHIFT);
> +                       (chan->req << GDMA_RT305X_CTRL0_DST_REQ_SHIFT);
>         } else if (chan->desc->direction == DMA_DEV_TO_MEM) {
>                 src_addr = chan->fifo_addr;
>                 dst_addr = sg->dst_addr;
>                 ctrl0 = GDMA_REG_CTRL0_SRC_ADDR_FIXED |
> -                       (chan->slave_id << GDMA_RT305X_CTRL0_SRC_REQ_SHIFT) |
> +                       (chan->req << GDMA_RT305X_CTRL0_SRC_REQ_SHIFT) |
>                         (8 << GDMA_RT305X_CTRL0_DST_REQ_SHIFT);
>         } else if (chan->desc->direction == DMA_MEM_TO_MEM) {
>                 /*
> @@ -365,12 +363,12 @@ static int rt3883_gdma_start_transfer(struct gdma_dmaengine_chan *chan)
>                 dst_addr = chan->fifo_addr;
>                 ctrl0 = GDMA_REG_CTRL0_DST_ADDR_FIXED;
>                 ctrl1 = (32 << GDMA_REG_CTRL1_SRC_REQ_SHIFT) |
> -                       (chan->slave_id << GDMA_REG_CTRL1_DST_REQ_SHIFT);
> +                       (chan->req << GDMA_REG_CTRL1_DST_REQ_SHIFT);
>         } else if (chan->desc->direction == DMA_DEV_TO_MEM) {
>                 src_addr = chan->fifo_addr;
>                 dst_addr = sg->dst_addr;
>                 ctrl0 = GDMA_REG_CTRL0_SRC_ADDR_FIXED;
> -               ctrl1 = (chan->slave_id << GDMA_REG_CTRL1_SRC_REQ_SHIFT) |
> +               ctrl1 = (chan->req << GDMA_REG_CTRL1_SRC_REQ_SHIFT) |
>                         (32 << GDMA_REG_CTRL1_DST_REQ_SHIFT) |
>                         GDMA_REG_CTRL1_COHERENT;
>         } else if (chan->desc->direction == DMA_MEM_TO_MEM) {
> --
> 2.30.2
>
>