Re: [dpdk-dev] [PATCH v5 2/3] PCI: support MMIO in rte_pci_ioport_map/unap/read/write

["谢华伟(此时此刻）" <huawei.xhw@alibaba-inc.com>]

On 2021/1/12 16:23, Maxime Coquelin wrote:
> Title should be something like:
>
> "bus/pci: support MMIO in PCI ioport accessors
>
> On 10/22/20 5:51 PM, 谢华伟(此时此刻） wrote:
>> From: "huawei.xhw" <huawei.xhw@alibaba-inc.com>
>>
>> If IO BAR, we get PIO address.
>> If MMIO BAR, we get mapped virtual address.
>> We distinguish PIO and MMIO by their address like how kernel does.
>> ioread/write8/16/32 is provided to access PIO/MMIO.
>> BTW, for virtio on arch other than x86, BAR flag indicates PIO but is mapped.
> No acronym in the commit message.
BTW? fixed. PIO(programmed IO) and MMIO(memory mapped IO) explained.
> Also, I am not sure to understand this comment.
> Does it means in the case of ARM for example, the IORESOURCE_IO flag is
> set but the base address is above PIO_MAX?

ARM doesn't have PIO but only MMIO.  The device sets IORESOURCE_IO flag 
anyway.

Should i remove this message as it causes confuse?

>
>> Signed-off-by: huawei.xhw <huawei.xhw@alibaba-inc.com>
> As in previous patch, we need your full name for the sign-off.
fixed.
>
>> ---
>>   drivers/bus/pci/linux/pci.c     |   4 --
>>   drivers/bus/pci/linux/pci_uio.c | 123 ++++++++++++++++++++++++++--------------
>>   2 files changed, 82 insertions(+), 45 deletions(-)
>>
>> diff --git a/drivers/bus/pci/linux/pci.c b/drivers/bus/pci/linux/pci.c
>> index 0f38abf..0dc99e9 100644
>> --- a/drivers/bus/pci/linux/pci.c
>> +++ b/drivers/bus/pci/linux/pci.c
>> @@ -715,8 +715,6 @@ int rte_pci_write_config(const struct rte_pci_device *device,
>>   		break;
>>   #endif
>>   	case RTE_PCI_KDRV_IGB_UIO:
>> -		pci_uio_ioport_read(p, data, len, offset);
>> -		break;
> I think this part should be in patch 1.

Patch 1 handles IO port map.

Patch 2 unifies IO/MMIO.

Patch 3 handles vfio.

I feel current split is more clear.

>
>>   	case RTE_PCI_KDRV_UIO_GENERIC:
>>   		pci_uio_ioport_read(p, data, len, offset);
>>   		break;
>> @@ -736,8 +734,6 @@ int rte_pci_write_config(const struct rte_pci_device *device,
>>   		break;
>>   #endif
>>   	case RTE_PCI_KDRV_IGB_UIO:
>> -		pci_uio_ioport_write(p, data, len, offset);
>> -		break;
> Same here.
>
>>   	case RTE_PCI_KDRV_UIO_GENERIC:
>>   		pci_uio_ioport_write(p, data, len, offset);
>>   		break;
>> diff --git a/drivers/bus/pci/linux/pci_uio.c b/drivers/bus/pci/linux/pci_uio.c
>> index 01f2a40..c19382f 100644
>> --- a/drivers/bus/pci/linux/pci_uio.c
>> +++ b/drivers/bus/pci/linux/pci_uio.c
>> @@ -379,14 +379,9 @@
>>   	char buf[BUFSIZ];
>>   	uint64_t phys_addr, end_addr, flags;
>>   	unsigned long base;
>> +	bool iobar;
>>   	int i;
>>   
>> -	if (rte_eal_iopl_init() != 0) {
>> -		RTE_LOG(ERR, EAL, "%s(): insufficient ioport permissions for PCI device %s\n",
>> -			__func__, dev->name);
>> -		return -1;
>> -	}
>> -
>>   	/* open and read addresses of the corresponding resource in sysfs */
>>   	snprintf(filename, sizeof(filename), "%s/" PCI_PRI_FMT "/resource",
>>   		rte_pci_get_sysfs_path(), dev->addr.domain, dev->addr.bus,
>> @@ -408,15 +403,30 @@
>>   		&end_addr, &flags) < 0)
>>   		goto error;
>>   
>> -	if (!(flags & IORESOURCE_IO)) {
>> -		RTE_LOG(ERR, EAL, "%s(): bar resource other than IO is not supported\n", __func__);
>> +	if (flags & IORESOURCE_IO) {
>> +		iobar = 1;
>> +		base = (unsigned long)phys_addr;
>> +		RTE_LOG(INFO, EAL, "%s(): PIO BAR %08lx detected\n", __func__, base);
>> +	} else if (flags & IORESOURCE_MEM) {
>> +		iobar = 0;
>> +		base = (unsigned long)dev->mem_resource[bar].addr;
>> +		RTE_LOG(INFO, EAL, "%s(): MMIO BAR %08lx detected\n", __func__, base);
>> +	} else {
>> +		RTE_LOG(ERR, EAL, "%s(): unknown BAR type\n", __func__);
>> +		goto error;
>> +	}
>> +
>> +
>> +	if (iobar && rte_eal_iopl_init() != 0) {
>> +		RTE_LOG(ERR, EAL, "%s(): insufficient ioport permissions for PCI device %s\n",
>> +			__func__, dev->name);
>>   		goto error;
>>   	}
>> -	base = (unsigned long)phys_addr;
>> -	RTE_LOG(INFO, EAL, "%s(): PIO BAR %08lx detected\n", __func__, base);
>>   
>> -	if (base > UINT16_MAX)
>> +	if (iobar && (base > UINT16_MAX)) {
>> +		RTE_LOG(ERR, EAL, "%s(): %08lx too large PIO resource\n", __func__, base);
>>   		goto error;
>> +	}
> It looks like above check could be moved directly to (flags &
> IORESOURCE_IO) case, so iobar boolean is not needed.
yes, code is more clear with your suggestion.