Re: [Bugfix 2/3] eata: Implement PCI driver to manage eata PCI devices

[Hannes Reinecke]

On 09/14/2015 05:08 AM, Jiang Liu wrote:
> Previously the eata driver just grabs and accesses eata PCI devices
> without implementing a PCI device driver, that causes troubles with
> latest IRQ related
> 
> Commit 991de2e59090 ("PCI, x86: Implement pcibios_alloc_irq() and
> pcibios_free_irq()") changes the way to allocate PCI legacy IRQ
> for PCI devices on x86 platforms. Instead of allocating PCI legacy
> IRQs when pcibios_enable_device() gets called, now pcibios_alloc_irq()
> will be called by pci_device_probe() to allocate PCI legacy IRQs
> when binding PCI drivers to PCI devices.
> 
> But the eata driver directly accesses PCI devices without implementing
> corresponding PCI drivers, so pcibios_alloc_irq() won't be called for
> those PCI devices and wrong IRQ number may be used to manage the PCI
> device.
> 
> This patch implements a PCI device driver to manage eata PCI devices,
> so eata driver could properly cooperate with the PCI core. It also
> provides headroom for PCI hotplug with eata driver.
> 
> Signed-off-by: Jiang Liu <jiang.liu@xxxxxxxxxxxxxxx>
> ---
>  drivers/scsi/eata.c |  170 ++++++++++++++++++++++-----------------------------
>  1 file changed, 74 insertions(+), 96 deletions(-)
> 
> diff --git a/drivers/scsi/eata.c b/drivers/scsi/eata.c
> index b45d3b532b70..b92e6856f909 100644
> --- a/drivers/scsi/eata.c
> +++ b/drivers/scsi/eata.c
> @@ -850,10 +850,6 @@ static unsigned long io_port[] = {
>  	/* First ISA */
>  	0x1f0,
>  
> -	/* Space for MAX_PCI ports possibly reported by PCI_BIOS */
> -	SKIP, SKIP, SKIP, SKIP, SKIP, SKIP, SKIP, SKIP,
> -	SKIP, SKIP, SKIP, SKIP, SKIP, SKIP, SKIP, SKIP,
> -
>  	/* MAX_EISA ports */
>  	0x1c88, 0x2c88, 0x3c88, 0x4c88, 0x5c88, 0x6c88, 0x7c88, 0x8c88,
>  	0x9c88, 0xac88, 0xbc88, 0xcc88, 0xdc88, 0xec88, 0xfc88,
> @@ -1024,60 +1020,13 @@ static int read_pio(unsigned long iobase, ushort * start, ushort * end)
>  	return 0;
>  }
>  
> -static struct pci_dev *get_pci_dev(unsigned long port_base)
> -{
> -#if defined(CONFIG_PCI)
> -	unsigned int addr;
> -	struct pci_dev *dev = NULL;
> -
> -	while ((dev = pci_get_class(PCI_CLASS_STORAGE_SCSI << 8, dev))) {
> -		addr = pci_resource_start(dev, 0);
> -
> -#if defined(DEBUG_PCI_DETECT)
> -		printk("%s: get_pci_dev, bus %d, devfn 0x%x, addr 0x%x.\n",
> -		       driver_name, dev->bus->number, dev->devfn, addr);
> -#endif
> -
> -		/* we are in so much trouble for a pci hotplug system with this driver
> -		 * anyway, so doing this at least lets people unload the driver and not
> -		 * cause memory problems, but in general this is a bad thing to do (this
> -		 * driver needs to be converted to the proper PCI api someday... */
> -		pci_dev_put(dev);
> -		if (addr + PCI_BASE_ADDRESS_0 == port_base)
> -			return dev;
> -	}
> -#endif				/* end CONFIG_PCI */
> -	return NULL;
> -}
> -
> -static void enable_pci_ports(void)
> -{
> -#if defined(CONFIG_PCI)
> -	struct pci_dev *dev = NULL;
> -
> -	while ((dev = pci_get_class(PCI_CLASS_STORAGE_SCSI << 8, dev))) {
> -#if defined(DEBUG_PCI_DETECT)
> -		printk("%s: enable_pci_ports, bus %d, devfn 0x%x.\n",
> -		       driver_name, dev->bus->number, dev->devfn);
> -#endif
> -
> -		if (pci_enable_device(dev))
> -			printk
> -			    ("%s: warning, pci_enable_device failed, bus %d devfn 0x%x.\n",
> -			     driver_name, dev->bus->number, dev->devfn);
> -	}
> -
> -#endif				/* end CONFIG_PCI */
> -}
> -
>  static int port_detect(unsigned long port_base, unsigned int j,
> -		struct scsi_host_template *tpnt)
> +		       struct scsi_host_template *tpnt, struct pci_dev *pdev)
>  {
>  	unsigned char irq, dma_channel, subversion, i, is_pci = 0;
>  	unsigned char protocol_rev;
>  	struct eata_info info;
>  	char *bus_type, dma_name[16];
> -	struct pci_dev *pdev;
>  	/* Allowed DMA channels for ISA (0 indicates reserved) */
>  	unsigned char dma_channel_table[4] = { 5, 6, 7, 0 };
>  	struct Scsi_Host *shost;
> @@ -1199,15 +1148,8 @@ static int port_detect(unsigned long port_base, unsigned int j,
>  		    ("%s: warning, LEVEL triggering is suggested for IRQ %u.\n",
>  		     name, irq);
>  
> -	if (is_pci) {
> -		pdev = get_pci_dev(port_base);
> -		if (!pdev)
> -			printk
> -			    ("%s: warning, failed to get pci_dev structure.\n",
> -			     name);
> -	} else
> -		pdev = NULL;
> -
> +	if (is_pci && !pdev)
> +		printk("%s: warning, failed to get pci_dev structure.\n", name);
>  	if (pdev && (irq != pdev->irq)) {
>  		printk("%s: IRQ %u mapped to IO-APIC IRQ %u.\n", name, irq,
>  		       pdev->irq);
> @@ -1510,14 +1452,17 @@ static int option_setup(char *str)
>  }
>  
>  static unsigned int port_probe(unsigned long port_base,
> -			       struct scsi_host_template *tpnt)
> +			       struct scsi_host_template *tpnt,
> +			       struct pci_dev *pdev)
>  {
>  	int id;
>  
>  	id = ida_simple_get(&eata_ida, 0, MAX_BOARDS, GFP_KERNEL);
>  	if (id >= 0) {
>  		set_bit(id, eata_board_bitmap);
> -		if (port_detect(port_base, id, tpnt))
> +		if (pdev)
> +			dev_set_drvdata(&pdev->dev, (void *)(long)id);
> +		if (port_detect(port_base, id, tpnt, pdev))
>  			return id;
>  		clear_bit(id, eata_board_bitmap);
>  		ida_simple_remove(&eata_ida, id);
> @@ -1526,42 +1471,81 @@ static unsigned int port_probe(unsigned long port_base,
>  	return -1;
>  }
>  
> -static void add_pci_ports(void)
> -{
> -#if defined(CONFIG_PCI)
> -	unsigned int addr, k;
> -	struct pci_dev *dev = NULL;
> -
> -	for (k = 0; k < MAX_PCI; k++) {
> +#ifdef CONFIG_PCI
> +static int eata2x_pci_device_count;
>  
> -		if (!(dev = pci_get_class(PCI_CLASS_STORAGE_SCSI << 8, dev)))
> -			break;
> +static int eata2x_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
> +{
> +	int i, ret = -ENXIO;
> +	resource_size_t addr;
> +	unsigned long port_base;
> +	struct scsi_host_template *tpnt = (void *)id->driver_data;
>  
> -		if (pci_enable_device(dev)) {
> +	if (pci_enable_device(dev)) {
>  #if defined(DEBUG_PCI_DETECT)
> -			printk
> -			    ("%s: detect, bus %d, devfn 0x%x, pci_enable_device failed.\n",
> -			     driver_name, dev->bus->number, dev->devfn);
> +		pr_warn("%s: detect, bus %d, devfn 0x%x, pci_enable_device failed.\n",
> +			driver_name, dev->bus->number, dev->devfn);
>  #endif
> +		goto out_error;
> +	}
>  
> -			continue;
> -		}
> -
> -		addr = pci_resource_start(dev, 0);
> -
> +	addr = pci_resource_start(dev, 0);
> +	port_base = addr + PCI_BASE_ADDRESS_0;
>  #if defined(DEBUG_PCI_DETECT)
> -		printk("%s: detect, seq. %d, bus %d, devfn 0x%x, addr 0x%x.\n",
> -		       driver_name, k, dev->bus->number, dev->devfn, addr);
> +	printk("%s: detect, bus %d, devfn 0x%x, addr 0x%x.\n",
> +	       driver_name, dev->bus->number, dev->devfn, (unsigned int)addr);
>  #endif
>  
> -		/* Order addresses according to rev_scan value */
> -		io_port[MAX_INT_PARAM + (rev_scan ? (MAX_PCI - k) : (1 + k))] =
> -		    addr + PCI_BASE_ADDRESS_0;
> +	if (setup_done) {
> +		/*
> +		 * Handle kernel or module parameter
> +		 * . probe board if its port is specified by user
> +		 * . otherwise ignore the board
> +		 */
> +		for (i = 1; i < MAX_INT_PARAM; i++)
> +			if (io_port[i] == port_base) {
> +				io_port[i] = SKIP;
> +				break;
> +			}
> +		if (i >= MAX_INT_PARAM)
> +			goto out_disable_device;
> +	}
Hmm. I must admit I don't like the 'setup_done' thingie. As the driver
is now converted to a 'real' PCI device we should be using driver-core
mechanisms to avoid driver binding, not the prefabricated 'setup_done'
variable.
Can't we just do away with it completely?

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@xxxxxxx			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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