Re: [PATCH v2 1/2] PRUSS UIO driver support

[Thomas Gleixner]

On Mon, 21 Feb 2011, Pratheesh Gangadhar wrote:
> +static irqreturn_t pruss_handler(int irq, struct uio_info *dev_info)
> +{
> +	void __iomem *int_enable_reg = dev_info->mem[0].internal_addr
> +					+ PRUSS_INTC_HIER;
> +	void __iomem *int_status_reg = dev_info->mem[0].internal_addr
> +					+ PRUSS_INTC_HIPIR+((irq-1) << 2);

  	void __iomem *base = dev_info->mem[0].internal_addr;
	void __iomem *int_enable_reg = base + PRUSS_INTC_HIER;
	....

Makes that readable.

> +	/* Is interrupt enabled and active ? */
> +	if (!(ioread32(int_enable_reg) & (1<<(irq-1))) &&
> +		 (ioread32(int_status_reg) & PRUSS_INTC_HIPIR_INTPEND_MASK))
> +		return IRQ_NONE;

  That returns when the interrupt is disabled _AND_ pending. It should
  return when the interrupt is disabled _OR_ not pending.
> +
> +	/* Disable interrupt */
> +	iowrite32(ioread32(int_enable_reg) & ~(1<<(irq-1)),
> +		int_enable_reg);

Chosing shorter variable names avoid those line breaks all over the
place.

> +	return IRQ_HANDLED;
> +}
> +
> +static void pruss_cleanup(struct platform_device *dev, struct uio_info *info)
> +{
> +	int count;

New line between variables and code please

> +	if (info) {

This check is silly. pruss_probe() returns right away when it cannot
allocate info. pruss_remove() is never called when info == NULL

> +		for (count = 0; count < MAX_PRUSS_EVTOUT_INSTANCE; count++) {
> +			uio_unregister_device(&info[count]);
> +			kfree(info[count].name);
> +			iounmap(info[count].mem[0].internal_addr);

Why do you map/unmap the same physical address 8 times ????

> +		}
> +		if (ddr_virt_addr)
> +			dma_free_coherent(&dev->dev, info[0].mem[2].size,
> +					  info[0].mem[2].internal_addr,
> +					  info[0].mem[2].addr);
> +		kfree(info);
> +	}
> +	if (pruss_clk != NULL)

Silly check as well.

> +		clk_put(pruss_clk);
> +}
> +
> +static int __devinit pruss_probe(struct platform_device *dev)
> +{
> +	int ret = -ENODEV, count = 0;
> +	struct resource *regs_pruram, *regs_l3ram, *regs_ddr;
> +	char *string;
> +
> +	/* Power on PRU in case its not done as part of boot-loader */
> +	pruss_clk = clk_get(&dev->dev, "pruss");
> +	if (IS_ERR(pruss_clk)) {
> +		dev_err(&dev->dev, "Failed to get clock\n");
> +		ret = PTR_ERR(pruss_clk);
> +		return ret;
> +	} else {
> +		clk_enable(pruss_clk);
> +	}
> +
> +	info = kzalloc(sizeof(struct uio_info) * MAX_PRUSS_EVTOUT_INSTANCE,
> +		       GFP_KERNEL);
> +	if (info == NULL)

  if (!info)

> +		return -ENOMEM;

  Leaves the clock enabled

> +	regs_pruram = platform_get_resource(dev, IORESOURCE_MEM, 0);
> +	if (!regs_pruram) {
> +		dev_err(&dev->dev, "No memory resource specified\n");
> +		goto out_free;
> +	}
> +
> +	regs_l3ram = platform_get_resource(dev, IORESOURCE_MEM, 1);
> +	if (!regs_l3ram) {
> +		dev_err(&dev->dev, "No memory resource specified\n");
> +		goto out_free;
> +	}
> +
> +	regs_ddr = platform_get_resource(dev, IORESOURCE_MEM, 2);
> +	if (!regs_ddr) {
> +		dev_err(&dev->dev, "No memory resource specified\n");
> +		goto out_free;
> +	}
> +	ddr_virt_addr =
> +	    dma_alloc_coherent(&dev->dev, regs_ddr->end - regs_ddr->start + 1,
> +			       &ddr_phy_addr, GFP_KERNEL | GFP_DMA);
> +	if (!ddr_virt_addr) {
> +		dev_err(&dev->dev, "Could not allocate external memory\n");
> +		goto out_free;
> +	}
> +
> +	for (count = 0; count < MAX_PRUSS_EVTOUT_INSTANCE; count++) {

Sigh. Can't you have a pointer struct uio_info *p and do the following.

      for (cnt = 0; p = info; cnt < MAX_PRUSS_EVTOUT_INSTANCE; cnt++, p++) {

      	       p->mem[0] ...

> +		info[count].mem[0].addr = regs_pruram->start;
> +		info[count].mem[0].size =
> +		    regs_pruram->end - regs_pruram->start + 1;
> +		if (!info[count].mem[0].addr ||
> +			!(info[count].mem[0].size - 1)) {

All you catch is size == 0. So with size == 1 it works ???

> +			dev_err(&dev->dev, "Invalid memory resource\n");
> +			goto out_free;
> +		}
> +		info[count].mem[0].internal_addr =
> +		    ioremap(regs_pruram->start, info[count].mem[0].size);

That's redundant to remap the same address 8 times. That and the check
above should be done before the loop and the result used in the loop.

> +		if (!info[count].mem[0].internal_addr) {
> +			dev_err(&dev->dev,
> +				"Can't remap memory address range\n");
> +			goto out_free;
> +		}
> +		info[count].mem[0].memtype = UIO_MEM_PHYS;
> +
> +		info[count].mem[1].addr = regs_l3ram->start;
> +		info[count].mem[1].size =
> +		    regs_l3ram->end - regs_l3ram->start + 1;
> +		if (!info[count].mem[1].addr ||
> +			!(info[count].mem[1].size - 1)) {
> +			dev_err(&dev->dev, "Invalid memory resource\n");
> +			goto out_free;
> +		}

No need to check the same thing over and over.

> +		info[count].mem[1].memtype = UIO_MEM_PHYS;
> +
> +		info[count].mem[2].internal_addr = ddr_virt_addr;
> +		info[count].mem[2].addr = ddr_phy_addr;
> +		info[count].mem[2].size = regs_ddr->end - regs_ddr->start + 1;
> +		info[count].mem[2].memtype = UIO_MEM_PHYS;
> +
> +		string = kzalloc(20, GFP_KERNEL);
> +		sprintf(string, "pruss_evt%d", count);
> +		info[count].name = string;

  kasprintf() please

> +		info[count].version = "0.50";
> +
> +		/* Register PRUSS IRQ lines */
> +		info[count].irq = IRQ_DA8XX_EVTOUT0 + count;
> +
> +		info[count].irq_flags = 0;

  Is already zero

> +		info[count].handler = pruss_handler;
> +
> +		ret = uio_register_device(&dev->dev, &info[count]);
> +
> +		if (ret < 0)
> +			goto out_free;
> +	}
> +
> +	platform_set_drvdata(dev, info);
> +	return 0;
> +
> +out_free:
> +	pruss_cleanup(dev, info);
> +	return ret;
> +}
> +
> +static int __devexit pruss_remove(struct platform_device *dev)
> +{
> +	struct uio_info *info = platform_get_drvdata(dev);

Empty line between variables and code.

> +	pruss_cleanup(dev, info);
> +	platform_set_drvdata(dev, NULL);
> +	return 0;

Thanks,

	tglx
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