[RFC][PATCH 2/2] powerpc/fsl-pci Make PCIe hotplug work with Freescale
Rojhalat Ibrahim
imr at rtschenk.de
Wed Apr 3 18:09:17 EST 2013
Hi Kumar,
what about this patch? Any reasons not to apply?
Rojhalat
On Monday 18 March 2013 10:22:40 Rojhalat Ibrahim wrote:
> On Thursday 14 March 2013 15:35:40 Kumar Gala wrote:
> > On Mar 14, 2013, at 4:43 AM, Rojhalat Ibrahim wrote:
> > > On Wednesday 13 March 2013 14:07:16 Kumar Gala wrote:
> > >> diff --git a/arch/powerpc/sysdev/fsl_pci.c
> > >> b/arch/powerpc/sysdev/fsl_pci.c
> > >> index 41bbcc4..b18c377 100644
> > >> --- a/arch/powerpc/sysdev/fsl_pci.c
> > >> +++ b/arch/powerpc/sysdev/fsl_pci.c
> > >> @@ -74,6 +74,35 @@ 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)) {
> > >> + if (fsl_pcie_check_link(hose))
> > >> + hose->indirect_type |= PPC_INDIRECT_TYPE_NO_PCIE_LINK;
> > >> + else
> > >> + hose->indirect_type &= ~PPC_INDIRECT_TYPE_NO_PCIE_LINK;
> > >> + }
> > >> + return indirect_read_config(bus, devfn, offset, len, val);
> > >> +}
> > >> +
> > >
> > > This does not work because fsl_indirect_read_config calls
> > > fsl_pcie_check_link which calls early_read_config_dword which eventually
> > > calls fsl_indirect_read_config, so the kernel hangs in a recursion loop.
> > > Below is a modified patch that does work.
> >
> > ok, that makes sense, but I guess now its making me question the following
statement:
> > > if ((bus->number == hose->first_busno) && (devfn == 0)) {
> >
> > Why do we have this conditional?
> >
> > - k
>
> Right. This is not necessary anymore. I modified the patch accordingly.
>
>
> Signed-off-by: Rojhalat Ibrahim <imr at rtschenk.de>
> ---
> arch/powerpc/include/asm/pci-bridge.h | 6 ++++
> arch/powerpc/sysdev/fsl_pci.c | 51
> +++++++++++++++++++++++++++++----- arch/powerpc/sysdev/indirect_pci.c |
> 10 ++----
> 3 files changed, 54 insertions(+), 13 deletions(-)
>
> diff --git a/arch/powerpc/include/asm/pci-bridge.h
> b/arch/powerpc/include/asm/pci-bridge.h index c0278f0..ffbc5fd 100644
> --- a/arch/powerpc/include/asm/pci-bridge.h
> +++ b/arch/powerpc/include/asm/pci-bridge.h
> @@ -120,6 +120,12 @@ extern void setup_indirect_pci(struct pci_controller*
> hose, resource_size_t cfg_addr,
> resource_size_t cfg_data, u32 flags);
>
> +extern int indirect_read_config(struct pci_bus *bus, unsigned int devfn,
> + int offset, int len, u32 *val);
> +
> +extern int indirect_write_config(struct pci_bus *bus, unsigned int devfn,
> + int offset, int len, u32 val);
> +
> static inline struct pci_controller *pci_bus_to_host(const struct pci_bus
> *bus) {
> return bus->sysdata;
> diff --git a/arch/powerpc/sysdev/fsl_pci.c b/arch/powerpc/sysdev/fsl_pci.c
> index 41bbcc4..9c0fcc9 100644
> --- a/arch/powerpc/sysdev/fsl_pci.c
> +++ b/arch/powerpc/sysdev/fsl_pci.c
> @@ -54,12 +54,22 @@ static void quirk_fsl_pcie_header(struct pci_dev *dev)
> return;
> }
>
> -static int __init fsl_pcie_check_link(struct pci_controller *hose)
> +static int fsl_indirect_read_config(struct pci_bus *, unsigned int,
> + int, int, u32 *);
> +
> +static int fsl_pcie_check_link(struct pci_controller *hose)
> {
> - u32 val;
> + u32 val = 0;
>
> if (hose->indirect_type & PPC_INDIRECT_TYPE_FSL_CFG_REG_LINK) {
> - early_read_config_dword(hose, 0, 0, PCIE_LTSSM, &val);
> + if (hose->ops->read == fsl_indirect_read_config) {
> + struct pci_bus bus;
> + bus.number = 0;
> + bus.sysdata = hose;
> + bus.ops = hose->ops;
> + indirect_read_config(&bus, 0, PCIE_LTSSM, 4, &val);
> + } else
> + early_read_config_dword(hose, 0, 0, PCIE_LTSSM, &val);
> if (val < PCIE_LTSSM_L0)
> return 1;
> } else {
> @@ -74,6 +84,33 @@ 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);
> +
> + if (fsl_pcie_check_link(hose))
> + hose->indirect_type |= PPC_INDIRECT_TYPE_NO_PCIE_LINK;
> + else
> + hose->indirect_type &= ~PPC_INDIRECT_TYPE_NO_PCIE_LINK;
> +
> + return indirect_read_config(bus, devfn, offset, len, val);
> +}
> +
> +static struct pci_ops fsl_indirect_pci_ops =
> +{
> + .read = fsl_indirect_read_config,
> + .write = 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);
> + hose->ops = &fsl_indirect_pci_ops;
> +}
> +
> #if defined(CONFIG_FSL_SOC_BOOKE) || defined(CONFIG_PPC_86xx)
>
> #define MAX_PHYS_ADDR_BITS 40
> @@ -469,8 +506,8 @@ int __init fsl_add_bridge(struct platform_device *pdev,
> int is_primary) if (!hose->private_data)
> goto no_bridge;
>
> - 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 (in_be32(&pci->block_rev1) < PCIE_IP_REV_3_0)
> hose->indirect_type |= PPC_INDIRECT_TYPE_FSL_CFG_REG_LINK;
> @@ -779,8 +816,8 @@ 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. "
> diff --git a/arch/powerpc/sysdev/indirect_pci.c
> b/arch/powerpc/sysdev/indirect_pci.c index 82fdad8..c6c8b52 100644
> --- a/arch/powerpc/sysdev/indirect_pci.c
> +++ b/arch/powerpc/sysdev/indirect_pci.c
> @@ -20,9 +20,8 @@
> #include <asm/pci-bridge.h>
> #include <asm/machdep.h>
>
> -static int
> -indirect_read_config(struct pci_bus *bus, unsigned int devfn, int offset,
> - int len, u32 *val)
> +int 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);
> volatile void __iomem *cfg_data;
> @@ -78,9 +77,8 @@ indirect_read_config(struct pci_bus *bus, unsigned int
> devfn, int offset, return PCIBIOS_SUCCESSFUL;
> }
>
> -static int
> -indirect_write_config(struct pci_bus *bus, unsigned int devfn, int offset,
> - int len, u32 val)
> +int indirect_write_config(struct pci_bus *bus, unsigned int devfn,
> + int offset, int len, u32 val)
> {
> struct pci_controller *hose = pci_bus_to_host(bus);
> volatile void __iomem *cfg_data;
>
>
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