[PATCH v11 3/3] dmaengine: add driver for Sophgo CV18XX/SG200X dmamux

[Christophe JAILLET]

Le 11/08/2024 à 07:16, Inochi Amaoto a écrit :
> Sophgo CV18XX/SG200X use DW AXI CORE with a multiplexer for remapping
> its request lines. The multiplexer supports at most 8 request lines.
> 
> Add driver for Sophgo CV18XX/SG200X DMA multiplexer.
> 
> Signed-off-by: Inochi Amaoto <inochiama at outlook.com>
> ---

Hi,

...

> +static void *cv1800_dmamux_route_allocate(struct of_phandle_args *dma_spec,
> +					  struct of_dma *ofdma)
> +{
> +	struct platform_device *pdev = of_find_device_by_node(ofdma->of_node);
> +	struct cv1800_dmamux_data *dmamux = platform_get_drvdata(pdev);
> +	struct cv1800_dmamux_map *map;
> +	struct llist_node *node;
> +	unsigned long flags;
> +	unsigned int chid, devid, cpuid;
> +	int ret;
> +
> +	if (dma_spec->args_count != DMAMUX_NCELLS) {
> +		dev_err(&pdev->dev, "invalid number of dma mux args\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	devid = dma_spec->args[0];
> +	cpuid = dma_spec->args[1];
> +	dma_spec->args_count = 1;
> +
> +	if (devid > MAX_DMA_MAPPING_ID) {
> +		dev_err(&pdev->dev, "invalid device id: %u\n", devid);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	if (cpuid > MAX_DMA_CPU_ID) {
> +		dev_err(&pdev->dev, "invalid cpu id: %u\n", cpuid);
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	dma_spec->np = of_parse_phandle(ofdma->of_node, "dma-masters", 0);
> +	if (!dma_spec->np) {
> +		dev_err(&pdev->dev, "can't get dma master\n");
> +		return ERR_PTR(-EINVAL);
> +	}
> +
> +	spin_lock_irqsave(&dmamux->lock, flags);
> +
> +	if (test_bit(devid, dmamux->mapped_peripherals)) {
> +		llist_for_each_entry(map, dmamux->reserve_maps.first, node) {
> +			if (map->peripheral == devid && map->cpu == cpuid)
> +				goto found;
> +		}
> +
> +		ret = -EINVAL;
> +		goto failed;
> +	} else {
> +		node = llist_del_first(&dmamux->free_maps);
> +		if (!node) {
> +			ret = -ENODEV;
> +			goto failed;
> +		}
> +
> +		map = llist_entry(node, struct cv1800_dmamux_map, node);
> +		llist_add(&map->node, &dmamux->reserve_maps);
> +		set_bit(devid, dmamux->mapped_peripherals);
> +	}
> +
> +found:
> +	chid = map->channel;
> +	map->peripheral = devid;
> +	map->cpu = cpuid;
> +
> +	regmap_set_bits(dmamux->regmap,
> +			DMAMUX_CH_REG(chid),
> +			DMAMUX_CH_SET(chid, devid));
> +
> +	regmap_update_bits(dmamux->regmap, CV1800_SDMA_DMA_INT_MUX,
> +			   DMAMUX_INT_CH_MASK(chid, cpuid),
> +			   DMAMUX_INT_CH_BIT(chid, cpuid));
> +
> +	spin_unlock_irqrestore(&dmamux->lock, flags);
> +
> +	dma_spec->args[0] = chid;
> +
> +	dev_dbg(&pdev->dev, "register channel %u for req %u (cpu %u)\n",
> +		chid, devid, cpuid);
> +
> +	return map;
> +
> +failed:
> +	spin_unlock_irqrestore(&dmamux->lock, flags);
> +	of_node_put(dma_spec->np);
> +	dev_err(&pdev->dev, "errno %d\n", ret);
> +	return ERR_PTR(ret);
> +

Nitpick: Unneeded empty new line.

> +}
> +
> +static int cv1800_dmamux_probe(struct platform_device *pdev)
> +{
> +	struct device *dev = &pdev->dev;
> +	struct device_node *mux_node = dev->of_node;
> +	struct cv1800_dmamux_data *data;
> +	struct cv1800_dmamux_map *tmp;
> +	struct device *parent = dev->parent;
> +	struct regmap *regmap = NULL;
> +	unsigned int i;
> +
> +	if (!parent)
> +		return -ENODEV;
> +
> +	regmap = device_node_to_regmap(parent->of_node);
> +	if (IS_ERR(regmap))
> +		return PTR_ERR(regmap);
> +
> +	data = devm_kmalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +
> +	spin_lock_init(&data->lock);
> +	init_llist_head(&data->free_maps);

Why init free_maps and not reserve_maps?
'data' is not zeroed, so it should be needed, IMHO.

Same for mapped_peripherals. It is not initialized.

I think that using devm_kzalloc() above is needed. (and 
init_llist_head(&data->free_maps) could then be removed, if you want)

Just my 2c.

> +
> +	for (i = 0; i <= MAX_DMA_CH_ID; i++) {
> +		tmp = devm_kmalloc(dev, sizeof(*tmp), GFP_KERNEL);
> +		if (!tmp) {
> +			/* It is OK for not allocating all channel */
> +			dev_warn(dev, "can not allocate channel %u\n", i);
> +			continue;
> +		}
> +
> +		init_llist_node(&tmp->node);
> +		tmp->channel = i;
> +		llist_add(&tmp->node, &data->free_maps);
> +	}
> +
> +	/* if no channel is allocated, the probe must fail */
> +	if (llist_empty(&data->free_maps))
> +		return -ENOMEM;
> +
> +	data->regmap = regmap;
> +	data->dmarouter.dev = dev;
> +	data->dmarouter.route_free = cv1800_dmamux_free;
> +
> +	platform_set_drvdata(pdev, data);
> +
> +	return of_dma_router_register(mux_node,
> +				      cv1800_dmamux_route_allocate,
> +				      &data->dmarouter);
> +}

...

CJ