linux-kernel - Re: [PATCH v2 2/3] dmaengine: dw-axi-dmac: Add support for StarFive JH7110 DMA

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Message-ID: <CAJM55Z_buj_CBKtJw=n_K-Ma4ZGP9pmy_uM20nLpJhTMNh=bJQ@mail.gmail.com>
Date:   Sun, 26 Feb 2023 15:25:23 +0100
From:   Emil Renner Berthing <emil.renner.berthing@...onical.com>
To:     Walker Chen <walker.chen@...rfivetech.com>
Cc:     Eugeniy Paltsev <Eugeniy.Paltsev@...opsys.com>,
        Vinod Koul <vkoul@...nel.org>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor@...nel.org>,
        Palmer Dabbelt <palmer@...belt.com>,
        Emil Renner Berthing <kernel@...il.dk>,
        dmaengine@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v2 2/3] dmaengine: dw-axi-dmac: Add support for StarFive
 JH7110 DMA

On Tue, 21 Feb 2023 at 15:04, Walker Chen <walker.chen@...rfivetech.com> wrote:
>
> Add DMA reset operation in device probe and use different configuration
> on CH_CFG registers according to compatible string.
>
> Signed-off-by: Walker Chen <walker.chen@...rfivetech.com>
> ---
>  .../dma/dw-axi-dmac/dw-axi-dmac-platform.c    | 19 +++++++++++++++++--
>  drivers/dma/dw-axi-dmac/dw-axi-dmac.h         |  3 +++
>  2 files changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> index bf85aa0979ec..858c4337650f 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
> @@ -25,6 +25,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/property.h>
> +#include <linux/reset.h>
>  #include <linux/slab.h>
>  #include <linux/types.h>
>
> @@ -86,7 +87,8 @@ static inline void axi_chan_config_write(struct axi_dma_chan *chan,
>
>         cfg_lo = (config->dst_multblk_type << CH_CFG_L_DST_MULTBLK_TYPE_POS |
>                   config->src_multblk_type << CH_CFG_L_SRC_MULTBLK_TYPE_POS);
> -       if (chan->chip->dw->hdata->reg_map_8_channels) {
> +       if (chan->chip->dw->hdata->reg_map_8_channels &&
> +           !chan->chip->dw->hdata->use_cfg2) {
>                 cfg_hi = config->tt_fc << CH_CFG_H_TT_FC_POS |
>                          config->hs_sel_src << CH_CFG_H_HS_SEL_SRC_POS |
>                          config->hs_sel_dst << CH_CFG_H_HS_SEL_DST_POS |
> @@ -1142,7 +1144,7 @@ static int dma_chan_terminate_all(struct dma_chan *dchan)
>         axi_chan_disable(chan);
>
>         ret = readl_poll_timeout_atomic(chan->chip->regs + DMAC_CHEN, val,
> -                                       !(val & chan_active), 1000, 10000);
> +                                       !(val & chan_active), 1000, DMAC_TIMEOUT_US);
>         if (ret == -ETIMEDOUT)
>                 dev_warn(dchan2dev(dchan),
>                          "%s failed to stop\n", axi_chan_name(chan));
> @@ -1416,6 +1418,18 @@ static int dw_probe(struct platform_device *pdev)
>         if (IS_ERR(chip->cfgr_clk))
>                 return PTR_ERR(chip->cfgr_clk);
>
> +       if (of_device_is_compatible(node, "starfive,jh7110-axi-dma")) {
> +               chip->resets = devm_reset_control_array_get_exclusive(&pdev->dev);
> +               if (IS_ERR(chip->resets))
> +                       return PTR_ERR(chip->resets);
> +
> +               ret = reset_control_deassert(chip->resets);
> +               if (ret)
> +                       return ret;
> +
> +               chip->dw->hdata->use_cfg2 = true;
> +       }
> +

In the future it would be great to use match data rather than all the
calls to of_device_is_compatible.

>         ret = parse_device_properties(chip);
>         if (ret)
>                 return ret;
> @@ -1560,6 +1574,7 @@ static const struct dev_pm_ops dw_axi_dma_pm_ops = {
>  static const struct of_device_id dw_dma_of_id_table[] = {
>         { .compatible = "snps,axi-dma-1.01a" },
>         { .compatible = "intel,kmb-axi-dma" },
> +       { .compatible = "starfive,jh7110-axi-dma" },
>         {}
>  };
>  MODULE_DEVICE_TABLE(of, dw_dma_of_id_table);
> diff --git a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> index e9d5eb0fd594..761d95691c02 100644
> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac.h
> @@ -21,6 +21,7 @@
>  #define DMAC_MAX_CHANNELS      16
>  #define DMAC_MAX_MASTERS       2
>  #define DMAC_MAX_BLK_SIZE      0x200000
> +#define DMAC_TIMEOUT_US                200000
>
>  struct dw_axi_dma_hcfg {
>         u32     nr_channels;
> @@ -33,6 +34,7 @@ struct dw_axi_dma_hcfg {
>         /* Register map for DMAX_NUM_CHANNELS <= 8 */
>         bool    reg_map_8_channels;
>         bool    restrict_axi_burst_len;
> +       bool    use_cfg2;
>  };
>
>  struct axi_dma_chan {
> @@ -70,6 +72,7 @@ struct axi_dma_chip {
>         struct clk              *core_clk;
>         struct clk              *cfgr_clk;
>         struct dw_axi_dma       *dw;
> +       struct reset_control    *resets;

This added field only seems to be written, but not read from anywhere.
With that fixed:

Reviewed-by: Emil Renner Berthing <emil.renner.berthing@...onical.com>

>  };
>
>  /* LLI == Linked List Item */
> --
> 2.17.1
>