Subject: Re: [PATCH] Make PCIe hotplug work with Freescale PCIe controllers

From: Chen Yuanquan-B41889 <[email-masked]>
Date: Tue, 12 Mar 2013 19:03:39 +0800

On 03/12/2013 06:30 PM, Rojhalat Ibrahim wrote:
> On Tuesday 12 March 2013 18:12:20 Chen Yuanquan-B41889 wrote:
>>>> -----Original Message-----
>>>> From: Linuxppc-dev [mailto:linuxppc-dev-bounces+tie-
>>>> fei.zang=[email-masked]] On Behalf Of Rojhalat Ibrahim
>>>> Sent: Tuesday, March 12, 2013 5:23 PM
>>>> To: Kumar Gala
>>>> Cc: [email-masked]
>>>> Subject: Re: [PATCH] Make PCIe hotplug work with Freescale PCIe
>>>> controllers
>>>>
>>>> On Monday 11 March 2013 12:17:42 Kumar Gala wrote:
>>>>> Rather than do it this way, we should do something like:
>>>>>
>>>>> fsl_indirect_read_config() {
>>>>>
>>>>> 	link check
>>>>> 	if (link)
>>>>> 	
>>>>> 		indirect_read_config()
>>>>>
>>>>> }
>>>>>
>>>>> and just add fsl_indirect_{r,w}_config into fsl_pci.c
>>>>>
>>>>> - k
>>>> Ok, how about this:
>> Yeah, this patch can solve the problem of PCI-e bus rescan which a PCI-e
>> EP is added to RC
>> after RC booting up. If RC boots up without EP added, the original code
>> will set the PCI-e
>> bus as no link even if you add a EP to RC during RC's runtime.
>>
>> Regards,
>> Yuanquan
>>
> Right. The EP is only added if you first do "echo 1 > /sys/bus/pci/rescan".
>
>     Rojhalat
>

The following patch can solve your issue of "only added if you first ...":

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 5b3771a..c1298d0 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -730,11 +730,12 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, 
struct

                 /* Prevent assigning a bus number that already exists.
                  * This can happen when a bridge is hot-plugged */
-               if (pci_find_bus(pci_domain_nr(bus), max+1))
-                       goto out;
-               child = pci_add_new_bus(bus, dev, ++max);
-               if (!child)
-                       goto out;
+               child = pci_find_bus(pci_domain_nr(bus), max+1);
+               if (!child) {
+                       child = pci_add_new_bus(bus, dev, ++max);
+                       if (!child)
+                               goto out;
+               }
                 buses = (buses & 0xff000000)
                       | ((unsigned int)(child->primary) <<  0)
                       | ((unsigned int)(child->secondary) <<  8)

There are still some issues about powerpc PCI-e rescan. For example, add 
a Intel e1000e
ethernet card or silicon PCI-e_sata to powerpc PCI-e slot and boot the 
board. The EP can
work well with their driver. But if you "echo 1 > 
/sys/bus/pci/device/xxx/remove" which
corresponds to Intel e1000e ethernet card or  silicon PCI-e_sata, then 
"echo 1" to rescan,
the device can be rescanned, but it will fail to load the corresponded 
driver due to hw_irq
and dma_set_mask error. The following  patch can solve the problem, but 
not a good method
to solve it.

diff --git a/arch/powerpc/kernel/pci-common.c 
b/arch/powerpc/kernel/pci-common.c
index 2476a32..f9b7f0f 100644
--- a/arch/powerpc/kernel/pci-common.c
+++ b/arch/powerpc/kernel/pci-common.c
@@ -1557,6 +1557,19 @@ int pcibios_enable_device(struct pci_dev *dev, 
int mask)
                 if (ppc_md.pcibios_enable_device_hook(dev))
                         return -EINVAL;

+       if (!dev->is_added) {
+               set_dev_node(&dev->dev, pcibus_to_node(dev->bus));
+
+               set_dma_ops(&dev->dev, pci_dma_ops);
+               set_dma_offset(&dev->dev, PCI_DRAM_OFFSET);
+
+               if (ppc_md.pci_dma_dev_setup)
+                       ppc_md.pci_dma_dev_setup(dev);
+
+               pci_read_irq_line(dev);
+               if (ppc_md.pci_irq_fixup)
+                       ppc_md.pci_irq_fixup(dev);
+       }
         return pci_enable_resources(dev, mask);
  }

Regards,
Yuanquan

>>>> Signed-off-by: Rojhalat Ibrahim <[email-masked]>
>>>> ---
>>>>
>>>>    arch/powerpc/sysdev/fsl_pci.c |   49
>>>>
>>>> ++++++++++++++++++++++++++++++++++++++----
>>>>
>>>>    1 file changed, 45 insertions(+), 4 deletions(-)
>>>>
>>>> diff --git a/arch/powerpc/sysdev/fsl_pci.c
>>>> b/arch/powerpc/sysdev/fsl_pci.c index 682084d..693db9f 100644
>>>> --- a/arch/powerpc/sysdev/fsl_pci.c
>>>> +++ b/arch/powerpc/sysdev/fsl_pci.c
>>>> @@ -36,6 +36,8 @@
>>>>
>>>>    static int fsl_pcie_bus_fixup, is_mpc83xx_pci;
>>>>
>>>> +static struct pci_ops *indirect_pci_ops;
>>>> +
>>>>
>>>>    static void quirk_fsl_pcie_header(struct pci_dev *dev)  {
>>>>    
>>>>    	u8 hdr_type;
>>>>
>>>> @@ -64,6 +66,45 @@ static int __init fsl_pcie_check_link(struct
>>>> pci_controller
>>>> *hose)
>>>>
>>>>    	return 0;
>>>>    
>>>>    }
>>>>
>>>> +static int fsl_indirect_read_config(struct pci_bus *bus, unsigned int
>>>> devfn,
>>>> +				    int offset, int len, u32 *val)
>>>> +{
>>>> +	struct pci_controller *hose = pci_bus_to_host(bus);
>>>> +
>>>> +	// check the link status
>>>> +	if ((bus->number == hose->first_busno) && (devfn == 0)) {
>>>> +		u32 ltssm = 0;
>>>> +		indirect_pci_ops->read(bus, 0, PCIE_LTSSM, 4, &ltssm);
>>>> +		if (ltssm < PCIE_LTSSM_L0) {
>>>> +			hose->indirect_type |= PPC_INDIRECT_TYPE_NO_PCIE_LINK;
>>>> +		} else {
>>>> +			hose->indirect_type &= ~PPC_INDIRECT_TYPE_NO_PCIE_LINK;
>>>> +		}
>>>> +	}
>>>> +	return indirect_pci_ops->read(bus, devfn, offset, len, val); }
>>>> +
>>>> +static int fsl_indirect_write_config(struct pci_bus *bus, unsigned int
>>>> devfn,
>>>> +				     int offset, int len, u32 val)
>>>> +{
>>>> +	return indirect_pci_ops->write(bus, devfn, offset, len, val); }
>>>> +
>>>> +static struct pci_ops fsl_indirect_pci_ops = {
>>>> +	.read = fsl_indirect_read_config,
>>>> +	.write = fsl_indirect_write_config,
>>>> +};
>>>> +
>>>> +static void __init fsl_setup_indirect_pci(struct pci_controller* hose,
>>>> +					  resource_size_t cfg_addr,
>>>> +					  resource_size_t cfg_data, u32 flags) {
>>>> +	setup_indirect_pci(hose, cfg_addr, cfg_data, flags);
>>>> +	indirect_pci_ops = hose->ops;
>>>> +	hose->ops = &fsl_indirect_pci_ops;
>>>> +}
>>>> +
>>>>
>>>>    #if defined(CONFIG_FSL_SOC_BOOKE) || defined(CONFIG_PPC_86xx)
>>>>    
>>>>    #define MAX_PHYS_ADDR_BITS	40
>>>>
>>>> @@ -461,8 +502,8 @@ int __init fsl_add_bridge(struct platform_device
>>>> *pdev, int is_primary)
>>>>
>>>>    	hose->first_busno = bus_range ? bus_range[0] : 0x0;
>>>>    	hose->last_busno = bus_range ? bus_range[1] : 0xff;
>>>>
>>>> -	setup_indirect_pci(hose, rsrc.start, rsrc.start + 0x4,
>>>> -		PPC_INDIRECT_TYPE_BIG_ENDIAN);
>>>> +	fsl_setup_indirect_pci(hose, rsrc.start, rsrc.start + 0x4,
>>>> +			       PPC_INDIRECT_TYPE_BIG_ENDIAN);
>>>>
>>>>    	if (early_find_capability(hose, 0, 0, PCI_CAP_ID_EXP)) {
>>>>    	
>>>>    		/* For PCIE read HEADER_TYPE to identify controler mode */ @@
>>>>
>>>> -766,8 +807,8 @@ int __init mpc83xx_add_bridge(struct device_node *dev)
>>>>
>>>>    		if (ret)
>>>>    		
>>>>    			goto err0;
>>>>    	
>>>>    	} else {
>>>>
>>>> -		setup_indirect_pci(hose, rsrc_cfg.start,
>>>> -				   rsrc_cfg.start + 4, 0);
>>>> +		fsl_setup_indirect_pci(hose, rsrc_cfg.start,
>>>> +				       rsrc_cfg.start + 4, 0);
>>>>
>>>>    	}
>>>>    	
>>>>    	printk(KERN_INFO "Found FSL PCI host bridge at 0x%016llx. "
>>>>
>>>> _______________________________________________
>>>> Linuxppc-dev mailing list
>>>> [email-masked]
>>>> https://lists.ozlabs.org/listinfo/linuxppc-dev
>> _______________________________________________
>> Linuxppc-dev mailing list
>> [email-masked]
>> https://lists.ozlabs.org/listinfo/linuxppc-dev
>
>