Re: [PATCH v4 2/3] dmaengine: dw-axi-dmac: Add support for StarFive JH7110 DMA

[Walker Chen <walker.chen@starfivetech.com>]

On 2023/3/6 22:39, Emil Renner Berthing wrote:
> On Mon, 6 Mar 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 match data. Update all uses of
>> of_device_is_compatible with of_device_get_match_data.
>>
>> Reviewed-by: Emil Renner Berthing <emil.renner.berthing@canonical.com>
> 
> Hi Walker,
> 
> Again please remove my Reviewed-by when you're adding a bunch of new
> code as you're doing here.

Sorry, I made another simple mistake.

> 
>> Signed-off-by: Walker Chen <walker.chen@starfivetech.com>
>> ---
>>  .../dma/dw-axi-dmac/dw-axi-dmac-platform.c    | 67 ++++++++++++++++---
>>  drivers/dma/dw-axi-dmac/dw-axi-dmac.h         |  2 +
>>  2 files changed, 61 insertions(+), 8 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..d1148f6fbcf9 100644
>> --- a/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
>> +++ b/drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c
>> @@ -21,10 +21,12 @@
>>  #include <linux/kernel.h>
>>  #include <linux/module.h>
>>  #include <linux/of.h>
>> +#include <linux/of_device.h>
>>  #include <linux/of_dma.h>
>>  #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>
>>
>> @@ -46,6 +48,12 @@
>>         DMA_SLAVE_BUSWIDTH_32_BYTES     | \
>>         DMA_SLAVE_BUSWIDTH_64_BYTES)
>>
>> +struct axi_dma_chip_config {
>> +       int (*apb_setup)(struct platform_device *pdev, struct axi_dma_chip *chip);
>> +       int (*reset_init)(struct platform_device *pdev);
>> +       bool use_cfg2;
>> +};
>> +
>>  static inline void
>>  axi_dma_iowrite32(struct axi_dma_chip *chip, u32 reg, u32 val)
>>  {
>> @@ -86,7 +94,8 @@ 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 +1151,7 @@ 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));
>> @@ -1367,13 +1376,33 @@ static int parse_device_properties(struct axi_dma_chip *chip)
>>         return 0;
>>  }
>>
>> +static int intel_apb_setup(struct platform_device *pdev, struct axi_dma_chip *chip)
>> +{
>> +       chip->apb_regs = devm_platform_ioremap_resource(pdev, 1);
>> +       if (IS_ERR(chip->apb_regs))
>> +               return PTR_ERR(chip->apb_regs);
>> +       else
>> +               return 0;
>> +}
>> +
>> +static int jh7110_reset_init(struct platform_device *pdev)
>> +{
>> +       struct reset_control *resets;
>> +
>> +       resets = devm_reset_control_array_get_exclusive(&pdev->dev);
>> +       if (IS_ERR(resets))
>> +               return PTR_ERR(resets);
>> +
>> +       return reset_control_deassert(resets);
>> +}
>> +
>>  static int dw_probe(struct platform_device *pdev)
>>  {
>> -       struct device_node *node = pdev->dev.of_node;
>>         struct axi_dma_chip *chip;
>>         struct resource *mem;
>>         struct dw_axi_dma *dw;
>>         struct dw_axi_dma_hcfg *hdata;
>> +       const struct axi_dma_chip_config *ccfg;
>>         u32 i;
>>         int ret;
>>
>> @@ -1402,10 +1431,21 @@ static int dw_probe(struct platform_device *pdev)
>>         if (IS_ERR(chip->regs))
>>                 return PTR_ERR(chip->regs);
>>
>> -       if (of_device_is_compatible(node, "intel,kmb-axi-dma")) {
>> -               chip->apb_regs = devm_platform_ioremap_resource(pdev, 1);
>> -               if (IS_ERR(chip->apb_regs))
>> -                       return PTR_ERR(chip->apb_regs);
>> +       ccfg = of_device_get_match_data(&pdev->dev);
>> +       if (ccfg) {
>> +               if (ccfg->apb_setup) {
>> +                       ret = ccfg->apb_setup(pdev, chip);
>> +                       if (ret)
>> +                               return ret;
>> +               }
>> +
>> +               if (ccfg->reset_init) {
>> +                       ret = ccfg->reset_init(pdev);
>> +                       if (ret)
>> +                               return ret;
>> +               }
>> +
>> +               chip->dw->hdata->use_cfg2 = ccfg->use_cfg2;
> 
> This claims and deasserts the resets before the clocks, whereas your
> previous versions did it after turning the clocks on. Which is the
> correct order?

The order has no problem, I have tested it with audio pwmdac on VisionFive2 board.

> 
> Also this certainly gets rid of of_device_is_compatible calls, but
> seems like a lot of code to do that. Did you consider something like
> 
> +#define AXI_DMA_FLAG_HAS_APB_REGS BIT(0)
> +#define AXI_DMA_FLAG_HAS_RESETS BIT(1)
> +#define AXI_DMA_FLAG_USE_CFG2 BIT(2)
> 
> +unsigned int flags = (uintptr_t)device_get_match_data(&pdev->dev);
> 
> -if (of_device_is_compatible(node, "intel,kmb-axi-dma")) {
> +if (flags & AXI_DMA_FLAG_HAS_APB_REGS) {
> 
> -if (of_device_is_compatible(node, "starfive,jh7110-axi-dma)) {
> +if (flags & AXI_DMA_FLAG_HAS_RESETS) {
> 
> +chip->dw->hwdata->use_cfg2 = !!(flags & AXI_DMA_FLAG_USE_CFG2);
> 
> -{ .compatible = "intel,kmb-axi-dma" },
> +{ .compatible = "intel,kmb-axi-dma", .data = (void
> *)AXI_DMA_FLAG_HAS_APB_REGS },
> +{ .compatible = "starive,jh7110-axi-dma", .data = (void
> *)(AXI_DMA_FLAG_HAS_RESETS | AXI_DMA_FLAG_USE_CFG2) },

Of course, it's better to have less code. I will try your method.

Thank you for taking the time to review and comment.

Best regards,
Walker