[PATCH v5 01/16] staging: mt7621-pci: use generic kernel pci subsystem read and write

Sergio Paracuellos sergio.paracuellos at gmail.com
Mon Jul 30 05:53:47 UTC 2018


On Mon, Jul 30, 2018 at 03:20:47PM +1000, NeilBrown wrote:
> On Fri, Jul 27 2018, Sergio Paracuellos wrote:
> 
> > map_bus callback is called before every .read/.write operation.
> > Implement it and change custom read write operations for the
> > pci subsystem generics. Make the probe function to don't use
> > legacy stuff and request bus resources directly. Get pci register
> > base from device tree.
> >
> > Signed-off-by: Sergio Paracuellos <sergio.paracuellos at gmail.com>
> 
> Thanks for your persistence!
> Something still isn't right ...  weird hangs, though my serial connector
> seems to be causing problems, which doesn't help.
> 
> I tried one patch at a time, and this first patch doesn't work.
> 
> It gets to  pcibios_align_resource() and crashes because in:
> 		if (start < PCIBIOS_MIN_MEM + hose->mem_resource->start)
> 			start = PCIBIOS_MIN_MEM + hose->mem_resource->start;
> 
> hose->mem_resource (which is pcie->mem_resource in mt7621_pci_probe())
> is NULL.
> 
> The call stack is:
> 
> [    2.490000] Call Trace:
> [    2.500000] [<804a5948>] pcibios_align_resource+0xa0/0xb4
> [    2.510000] [<8002ceb4>] __find_resource+0x150/0x230
> [    2.520000] [<8002d17c>] allocate_resource+0x1e8/0x224
> [    2.530000] [<80365e94>] pci_bus_alloc_resource+0x168/0x1c8
> [    2.540000] [<80374450>] _pci_assign_resource+0xa8/0x180
> [    2.550000] [<803749a4>] pci_assign_resource+0xf4/0x25c
> [    2.560000] [<80376820>] assign_requested_resources_sorted+0x90/0xe4
> [    2.570000] [<803771ec>] __assign_resources_sorted+0x110/0x4f8
> [    2.580000] [<80378618>] __pci_bus_assign_resources+0x74/0x240
> [    2.590000] [<803790c8>] pci_assign_unassigned_bus_resources+0x70/0xe8
> [    2.610000] [<804998f8>] mt7621_pci_probe+0x9e8/0xa44
> [    2.620000] [<803b1708>] platform_drv_probe+0x40/0x7c
> [    2.630000] [<803afc88>] driver_probe_device+0x31c/0x474
> [    2.640000] [<803afe94>] __driver_attach+0xb4/0x138
> [    2.650000] [<803ad730>] bus_for_each_dev+0x6c/0xb0
> [    2.650000] [<803ae968>] bus_add_driver+0x204/0x24c
> [    2.660000] [<803b07d8>] driver_register+0xd0/0x118
> [    2.670000] [<80001618>] do_one_initcall+0x84/0x19c
> [    2.680000] [<80741ed0>] kernel_init_freeable+0x248/0x250
> [    2.690000] [<805f549c>] kernel_init+0x14/0x110
> 
> So presumably the resources aren't getting initialised properly?

I think you cannot take this separately because it is mixing
pci legacy code with the new one. The 'hose' thing is PCI_LEGACY
and we are commented this here so it is wrong. With all patches 
applied the one to be called should be the one included in
pci_generic.c (arch/mips/pci/pci-generic.c +28) not the one
included in pci-legacy.c (arch/mips/pci/pci-legacy.c +49)

According to the last dmesg trace you included in the last series the
resources were properly being assigned, so I think the problem is
not there... I have only one concern about the ranges property in the
device tree which is using non prefetchable memory and I don't know
(because the pci controller for the mt7621 is not described in the datasheet)
if that is correct. According the mt7620 and mt7623 it should but I don't know. 
Also DT it is only mapping 256 bytes (pci configuration space) for registers
instead of mapping the whole 4 KB for all the pcie configuration space and I don't
know why... 
So I suppose taking all the patches together the problem persists and it hangs
when it tries to enable pci for the ahci... Can you please send me dmesg output
with patches applied and without the patches applied in order to check some stuff
I could be missing here? Because the code for the pci-legacy for the mips is doing
pretty much the same... Well, in a more manual way just mapping manually those it
needs. Maybe we can do that also first and try to figure out why the actual code
does not work... Anyway we should check that bridges have properly set the 'master'
bit before it hangs. This can be done just reading the PCI_COMMAND register with
pci_read_config_word. The bit it should be set is the bit 2.

Thanks for your effort and patience with this.

> 
> Thanks,
> NeilBrown

Best regards,
    Sergio Paracuellos
> 
> 
> > ---
> >  drivers/staging/mt7621-pci/pci-mt7621.c | 143 ++++++++++++++++++++++++++++++--
> >  1 file changed, 134 insertions(+), 9 deletions(-)
> >
> > diff --git a/drivers/staging/mt7621-pci/pci-mt7621.c b/drivers/staging/mt7621-pci/pci-mt7621.c
> > index 650e49b..b4f6de2 100644
> > --- a/drivers/staging/mt7621-pci/pci-mt7621.c
> > +++ b/drivers/staging/mt7621-pci/pci-mt7621.c
> > @@ -53,11 +53,16 @@
> >  #include <linux/delay.h>
> >  #include <linux/of.h>
> >  #include <linux/of_pci.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/of_address.h>
> > +#include <linux/of_irq.h>
> >  #include <linux/platform_device.h>
> >  
> >  #include <ralink_regs.h>
> >  #include <mt7621.h>
> >  
> > +#include "../../pci/pci.h"
> > +
> >  /*
> >   * These functions and structures provide the BIOS scan and mapping of the PCI
> >   * devices.
> > @@ -178,6 +183,32 @@ static int pcie_link_status = 0;
> >  #define PCI_ACCESS_WRITE_2 4
> >  #define PCI_ACCESS_WRITE_4 5
> >  
> > +/**
> > + * struct mt7621_pcie_port - PCIe port information
> > + * @base: IO mapped register base
> > + * @list: port list
> > + * @pcie: pointer to PCIe host info
> > + * @reset: pointer to port reset control
> > + */
> > +struct mt7621_pcie_port {
> > +	void __iomem *base;
> > +	struct list_head list;
> > +	struct mt7621_pcie *pcie;
> > +	struct reset_control *reset;
> > +};
> > +
> > +/**
> > + * struct mt7621_pcie - PCIe host information
> > + * @base: IO Mapped Register Base
> > + * @dev: Pointer to PCIe device
> > + * @ports: pointer to PCIe port information
> > + */
> > +struct mt7621_pcie {
> > +	void __iomem *base;
> > +	struct device *dev;
> > +	struct list_head ports;
> > +};
> > +
> >  static inline u32 mt7621_pci_get_cfgaddr(unsigned int bus, unsigned int slot,
> >  					 unsigned int func, unsigned int where)
> >  {
> > @@ -297,15 +328,27 @@ pci_config_write(struct pci_bus *bus, unsigned int devfn, int where, int size, u
> >  	}
> >  }
> >  
> > +static void __iomem *mt7621_pcie_map_bus(struct pci_bus *bus,
> > +					 unsigned int devfn, int where)
> > +{
> > +	struct mt7621_pcie *pcie = bus->sysdata;
> > +	u32 address = mt7621_pci_get_cfgaddr(bus->number, PCI_SLOT(devfn),
> > +					     PCI_FUNC(devfn), where);
> > +
> > +	writel(address, pcie->base + RALINK_PCI_CONFIG_ADDR);
> > +
> > +	return pcie->base + RALINK_PCI_CONFIG_DATA_VIRTUAL_REG + (where & 3);
> > +}
> > +
> >  struct pci_ops mt7621_pci_ops = {
> > -	.read		= pci_config_read,
> > -	.write		= pci_config_write,
> > +	.map_bus	= mt7621_pcie_map_bus,
> > +	.read		= pci_generic_config_read,
> > +	.write		= pci_generic_config_write,
> >  };
> >  
> >  static struct resource mt7621_res_pci_mem1;
> >  static struct resource mt7621_res_pci_io1;
> >  static struct pci_controller mt7621_controller = {
> > -	.pci_ops	= &mt7621_pci_ops,
> >  	.mem_resource	= &mt7621_res_pci_mem1,
> >  	.io_resource	= &mt7621_res_pci_io1,
> >  };
> > @@ -480,14 +523,67 @@ void setup_cm_memory_region(struct resource *mem_resource)
> >  	}
> >  }
> >  
> > +static int mt7621_pcie_parse_dt(struct mt7621_pcie *pcie)
> > +{
> > +	struct device *dev = pcie->dev;
> > +	struct device_node *node = dev->of_node;
> > +	struct resource regs;
> > +	const char *type;
> > +	int err;
> > +
> > +	type = of_get_property(node, "device_type", NULL);
> > +	if (!type || strcmp(type, "pci") != 0) {
> > +		dev_err(dev, "invalid \"device_type\" %s\n", type);
> > +		return -EINVAL;
> > +	}
> > +
> > +	err = of_address_to_resource(node, 0, &regs);
> > +	if (err) {
> > +		dev_err(dev, "missing \"reg\" property\n");
> > +		return err;
> > +	}
> > +
> > +	pcie->base = devm_pci_remap_cfg_resource(dev, &regs);
> > +	if (IS_ERR(pcie->base))
> > +		return PTR_ERR(pcie->base);
> > +
> > +	return 0;
> > +}
> > +
> >  static int mt7621_pci_probe(struct platform_device *pdev)
> >  {
> > +	struct device *dev = &pdev->dev;
> > +	struct mt7621_pcie *pcie;
> > +	struct pci_host_bridge *bridge;
> > +	struct pci_bus *bus, *child;
> > +	int err;
> > +	resource_size_t iobase = 0;
> >  	unsigned long val = 0;
> > +	LIST_HEAD(res);
> > +
> > +	if (!dev->of_node)
> > +		return -ENODEV;
> > +
> > +	bridge = devm_pci_alloc_host_bridge(dev, sizeof(*pcie));
> > +	if (!bridge)
> > +		return -ENODEV;
> > +
> > +	pcie = pci_host_bridge_priv(bridge);
> > +	pcie->dev = dev;
> > +	INIT_LIST_HEAD(&pcie->ports);
> > +
> > +	err = mt7621_pcie_parse_dt(pcie);
> > +	if (err) {
> > +		dev_err(dev, "Parsing DT failed\n");
> > +		return err;
> > +	}
> >  
> > +	/*
> >  	iomem_resource.start = 0;
> >  	iomem_resource.end = ~0;
> >  	ioport_resource.start = 0;
> >  	ioport_resource.end = ~0;
> > +	*/
> >  
> >  	val = RALINK_PCIE0_RST;
> >  	val |= RALINK_PCIE1_RST;
> > @@ -612,8 +708,8 @@ pcie(2/1/0) link status	pcie2_num	pcie1_num	pcie0_num
> >  	ioport_resource.end = mt7621_res_pci_io1.end;
> >  */
> >  
> > -	RALINK_PCI_MEMBASE = 0xffffffff; //RALINK_PCI_MM_MAP_BASE;
> > -	RALINK_PCI_IOBASE = RALINK_PCI_IO_MAP_BASE;
> > +	//RALINK_PCI_MEMBASE = 0xffffffff; //RALINK_PCI_MM_MAP_BASE;
> > +	//RALINK_PCI_IOBASE = RALINK_PCI_IO_MAP_BASE;
> >  
> >  	//PCIe0
> >  	if ((pcie_link_status & 0x1) != 0) {
> > @@ -665,11 +761,40 @@ pcie(2/1/0) link status	pcie2_num	pcie1_num	pcie0_num
> >  		write_config(0, 0, 0, 0x70c, val);
> >  	}
> >  
> > -	pci_load_of_ranges(&mt7621_controller, pdev->dev.of_node);
> > -	setup_cm_memory_region(mt7621_controller.mem_resource);
> > -	register_pci_controller(&mt7621_controller);
> > -	return 0;
> > +	err = devm_of_pci_get_host_bridge_resources(dev, 0, 0xff, &res,
> > +						    &iobase);
> > +	if (err) {
> > +		dev_err(dev, "Getting bridge resources failed\n");
> > +		return err;
> > +	}
> > +
> > +	err = devm_request_pci_bus_resources(dev, &res);
> > +	if (err)
> > +		return err;
> > +
> > +	list_splice_init(&res, &bridge->windows);
> > +	bridge->busnr = 0;
> > +	bridge->dev.parent = dev;
> > +	bridge->sysdata = pcie;
> > +	bridge->ops = &mt7621_pci_ops;
> > +	bridge->map_irq = of_irq_parse_and_map_pci;
> > +	bridge->swizzle_irq = pci_common_swizzle;
> >  
> > +	err = pci_scan_root_bus_bridge(bridge);
> > +	if (err < 0)
> > +		return err;
> > +
> > +	bus = bridge->bus;
> > +
> > +	pci_assign_unassigned_bus_resources(bus);
> > +	list_for_each_entry(child, &bus->children, node)
> > +		pcie_bus_configure_settings(child);
> > +
> > +	pci_bus_add_devices(bus);
> > +	//pci_load_of_ranges(&mt7621_controller, pdev->dev.of_node);
> > +	//setup_cm_memory_region(mt7621_controller.mem_resource);
> > +	//register_pci_controller(&mt7621_controller);
> > +	return 0;
> >  }
> >  
> >  int pcibios_plat_dev_init(struct pci_dev *dev)
> > -- 
> > 2.7.4




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