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

Emil Renner Berthing
2023-02-26T14:25:58Z

On Tue, 21 Feb 2023 at 15:04, Walker Chen <walker.chen@starfivetech.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@starfivetech.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@canonical.com>

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