Message-ID:
 <IA1PR20MB495361E9FD0CBAB62BF44BC1BB862@IA1PR20MB4953.namprd20.prod.outlook.com>
Date: Tue, 13 Aug 2024 08:31:34 +0800
From: Inochi Amaoto <inochiama@...look.com>
To: Christophe JAILLET <christophe.jaillet@...adoo.fr>, 
	Inochi Amaoto <inochiama@...look.com>, Vinod Koul <vkoul@...nel.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Chen Wang <unicorn_wang@...look.com>, Paul Walmsley <paul.walmsley@...ive.com>, 
	Palmer Dabbelt <palmer@...belt.com>, Albert Ou <aou@...s.berkeley.edu>
Cc: dmaengine@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-riscv@...ts.infradead.org
Subject: Re: [PATCH v11 3/3] dmaengine: add driver for Sophgo CV18XX/SG200X
 dmamux

On Sun, Aug 11, 2024 at 08:00:05AM GMT, Christophe JAILLET wrote:
> 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@...look.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.
> 

Thanks, I missed these two field. Although I got no error
when testing, it is necessary to fix this.

I think devm_kzalloc can only zero "mapped_peripherals".
It will be good to add missing init_llist_head for 
"reserve_maps".

Regards,
Inochi

> > +
> > +	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
> 
> 
> 
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