Hi Rahul,
> On 28 Sep 2021, at 19:18, Rahul Singh <rahul.si...@arm.com> wrote:
>
> Implement generic pci access functions to read/write the configuration
> space.
>
> Signed-off-by: Rahul Singh <rahul.si...@arm.com>
Reviewed-by: Bertrand Marquis <bertrand.marq...@arm.com>
Cheers
Bertrand
> ---
> Change in v3:
> - Remove PRI_pci as not used.
> - Replace uint32_t sbdf to pci_sbdf_t sbdf to avoid typecast
> Change in v2: Fixed comments
> ---
> xen/arch/arm/pci/pci-access.c | 57 ++++++++++++++++++++++++++++++
> xen/arch/arm/pci/pci-host-common.c | 19 ++++++++++
> xen/include/asm-arm/pci.h | 1 +
> 3 files changed, 77 insertions(+)
>
> diff --git a/xen/arch/arm/pci/pci-access.c b/xen/arch/arm/pci/pci-access.c
> index 3cd14a4b87..9f9aac43d7 100644
> --- a/xen/arch/arm/pci/pci-access.c
> +++ b/xen/arch/arm/pci/pci-access.c
> @@ -16,6 +16,7 @@
> #include <asm/io.h>
>
> #define INVALID_VALUE (~0U)
> +#define PCI_ERR_VALUE(len) GENMASK(0, len * 8)
>
> int pci_generic_config_read(struct pci_host_bridge *bridge, pci_sbdf_t sbdf,
> uint32_t reg, uint32_t len, uint32_t *value)
> @@ -72,6 +73,62 @@ int pci_generic_config_write(struct pci_host_bridge
> *bridge, pci_sbdf_t sbdf,
> return 0;
> }
>
> +static uint32_t pci_config_read(pci_sbdf_t sbdf, unsigned int reg,
> + unsigned int len)
> +{
> + uint32_t val = PCI_ERR_VALUE(len);
> + struct pci_host_bridge *bridge = pci_find_host_bridge(sbdf.seg,
> sbdf.bus);
> +
> + if ( unlikely(!bridge) )
> + return val;
> +
> + if ( unlikely(!bridge->ops->read) )
> + return val;
> +
> + bridge->ops->read(bridge, sbdf, reg, len, &val);
> +
> + return val;
> +}
> +
> +static void pci_config_write(pci_sbdf_t sbdf, unsigned int reg,
> + unsigned int len, uint32_t val)
> +{
> + struct pci_host_bridge *bridge = pci_find_host_bridge(sbdf.seg,
> sbdf.bus);
> +
> + if ( unlikely(!bridge) )
> + return;
> +
> + if ( unlikely(!bridge->ops->write) )
> + return;
> +
> + bridge->ops->write(bridge, sbdf, reg, len, val);
> +}
> +
> +/*
> + * Wrappers for all PCI configuration access functions.
> + */
> +
> +#define PCI_OP_WRITE(size, type) \
> + void pci_conf_write##size(pci_sbdf_t sbdf, \
> + unsigned int reg, type val) \
> +{ \
> + pci_config_write(sbdf, reg, size / 8, val); \
> +}
> +
> +#define PCI_OP_READ(size, type) \
> + type pci_conf_read##size(pci_sbdf_t sbdf, \
> + unsigned int reg) \
> +{ \
> + return pci_config_read(sbdf, reg, size / 8); \
> +}
> +
> +PCI_OP_READ(8, uint8_t)
> +PCI_OP_READ(16, uint16_t)
> +PCI_OP_READ(32, uint32_t)
> +PCI_OP_WRITE(8, uint8_t)
> +PCI_OP_WRITE(16, uint16_t)
> +PCI_OP_WRITE(32, uint32_t)
> +
> /*
> * Local variables:
> * mode: C
> diff --git a/xen/arch/arm/pci/pci-host-common.c
> b/xen/arch/arm/pci/pci-host-common.c
> index a08e06cea1..c5941b10e9 100644
> --- a/xen/arch/arm/pci/pci-host-common.c
> +++ b/xen/arch/arm/pci/pci-host-common.c
> @@ -236,6 +236,25 @@ err_exit:
> return err;
> }
>
> +/*
> + * This function will lookup an hostbridge based on the segment and bus
> + * number.
> + */
> +struct pci_host_bridge *pci_find_host_bridge(uint16_t segment, uint8_t bus)
> +{
> + struct pci_host_bridge *bridge;
> +
> + list_for_each_entry( bridge, &pci_host_bridges, node )
> + {
> + if ( bridge->segment != segment )
> + continue;
> + if ( (bus < bridge->cfg->busn_start) || (bus >
> bridge->cfg->busn_end) )
> + continue;
> + return bridge;
> + }
> +
> + return NULL;
> +}
> /*
> * Local variables:
> * mode: C
> diff --git a/xen/include/asm-arm/pci.h b/xen/include/asm-arm/pci.h
> index bb7eda6705..49c9622902 100644
> --- a/xen/include/asm-arm/pci.h
> +++ b/xen/include/asm-arm/pci.h
> @@ -81,6 +81,7 @@ int pci_generic_config_write(struct pci_host_bridge
> *bridge, pci_sbdf_t sbdf,
> uint32_t reg, uint32_t len, uint32_t value);
> void __iomem *pci_ecam_map_bus(struct pci_host_bridge *bridge,
> pci_sbdf_t sbdf, uint32_t where);
> +struct pci_host_bridge *pci_find_host_bridge(uint16_t segment, uint8_t bus);
>
> static always_inline bool is_pci_passthrough_enabled(void)
> {
> --
> 2.17.1
>
