Re: [PATCH] PCI: pci-bridge-emul: Set position of PCI capabilities to real HW value

From: Lorenzo Pieralisi
Date: Tue Aug 23 2022 - 06:43:07 EST

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On Sun, Jul 03, 2022 at 12:46:27PM +0200, Pali Rohár wrote:
> mvebu and aardvark HW have PCIe capabilities on different offset in PCI
> config space. Extend pci-bridge-emul.c code to allow setting custom driver
> custom value where PCIe capabilities starts.
>
> With this change PCIe capabilities of both drivers are reported at the same
> location as where they are reported by U-Boot - in their real HW offset.
>
> Signed-off-by: Pali Rohár <pali@xxxxxxxxxx>
> ---
> drivers/pci/controller/pci-aardvark.c | 1 +
> drivers/pci/controller/pci-mvebu.c | 1 +
> drivers/pci/pci-bridge-emul.c | 46 +++++++++++++++++----------
> drivers/pci/pci-bridge-emul.h | 2 ++
> 4 files changed, 33 insertions(+), 17 deletions(-)
>
> diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> index ffec82c8a523..32f97e71e0ca 100644
> --- a/drivers/pci/controller/pci-aardvark.c
> +++ b/drivers/pci/controller/pci-aardvark.c
> @@ -984,6 +984,7 @@ static int advk_sw_pci_bridge_init(struct advk_pcie *pcie)
> bridge->pcie_conf.rootcap = cpu_to_le16(PCI_EXP_RTCAP_CRSVIS);
>
> bridge->has_pcie = true;
> + bridge->pcie_start = PCIE_CORE_PCIEXP_CAP;
> bridge->data = pcie;
> bridge->ops = &advk_pci_bridge_emul_ops;
>
> diff --git a/drivers/pci/controller/pci-mvebu.c b/drivers/pci/controller/pci-mvebu.c
> index c1ffdb06c971..cb7cf3f4802f 100644
> --- a/drivers/pci/controller/pci-mvebu.c
> +++ b/drivers/pci/controller/pci-mvebu.c
> @@ -946,6 +946,7 @@ static int mvebu_pci_bridge_emul_init(struct mvebu_pcie_port *port)
> bridge->subsystem_vendor_id = ssdev_id & 0xffff;
> bridge->subsystem_id = ssdev_id >> 16;
> bridge->has_pcie = true;
> + bridge->pcie_start = PCIE_CAP_PCIEXP_OFF;

Is this patch to be applied against v6.0-rc1 ? Just asking, can't
find this define.

> bridge->data = port;
> bridge->ops = &mvebu_pci_bridge_emul_ops;
>
> diff --git a/drivers/pci/pci-bridge-emul.c b/drivers/pci/pci-bridge-emul.c
> index 9c2ca28e3ecf..dfbbe43ef518 100644
> --- a/drivers/pci/pci-bridge-emul.c
> +++ b/drivers/pci/pci-bridge-emul.c
> @@ -22,11 +22,7 @@
>
> #define PCI_BRIDGE_CONF_END PCI_STD_HEADER_SIZEOF
> #define PCI_CAP_SSID_SIZEOF (PCI_SSVID_DEVICE_ID + 2)
> -#define PCI_CAP_SSID_START PCI_BRIDGE_CONF_END
> -#define PCI_CAP_SSID_END (PCI_CAP_SSID_START + PCI_CAP_SSID_SIZEOF)
> #define PCI_CAP_PCIE_SIZEOF (PCI_EXP_SLTSTA2 + 2)
> -#define PCI_CAP_PCIE_START PCI_CAP_SSID_END
> -#define PCI_CAP_PCIE_END (PCI_CAP_PCIE_START + PCI_CAP_PCIE_SIZEOF)
>
> /**
> * struct pci_bridge_reg_behavior - register bits behaviors
> @@ -324,7 +320,7 @@ pci_bridge_emul_read_ssid(struct pci_bridge_emul *bridge, int reg, u32 *value)
> switch (reg) {
> case PCI_CAP_LIST_ID:
> *value = PCI_CAP_ID_SSVID |
> - (bridge->has_pcie ? (PCI_CAP_PCIE_START << 8) : 0);
> + ((bridge->pcie_start > bridge->ssid_start) ? (bridge->pcie_start << 8) : 0);
> return PCI_BRIDGE_EMUL_HANDLED;
>
> case PCI_SSVID_VENDOR_ID:
> @@ -365,12 +361,25 @@ int pci_bridge_emul_init(struct pci_bridge_emul *bridge,
> if (!bridge->pci_regs_behavior)
> return -ENOMEM;
>
> - if (bridge->subsystem_vendor_id)
> - bridge->conf.capabilities_pointer = PCI_CAP_SSID_START;
> - else if (bridge->has_pcie)
> - bridge->conf.capabilities_pointer = PCI_CAP_PCIE_START;
> - else
> - bridge->conf.capabilities_pointer = 0;
> + /* If ssid_start and pcie_start were not specified then choose the lowest possible value. */

Is this an assumption ? I don't see why this logic belongs in the
generic bridge emulation, I'd say that ssid_start, pcie_start and
the capabilities pointer should be set in the respective host
controller drivers, I don't think this belong in generic bridge
emulation code.

Thoughts ?

Lorenzo

> + if (!bridge->ssid_start && !bridge->pcie_start) {
> + if (bridge->subsystem_vendor_id)
> + bridge->ssid_start = PCI_BRIDGE_CONF_END;
> + if (bridge->has_pcie)
> + bridge->pcie_start = bridge->ssid_start + PCI_CAP_SSID_SIZEOF;
> + } else if (!bridge->ssid_start && bridge->subsystem_vendor_id) {
> + if (bridge->pcie_start - PCI_BRIDGE_CONF_END >= PCI_CAP_SSID_SIZEOF)
> + bridge->ssid_start = PCI_BRIDGE_CONF_END;
> + else
> + bridge->ssid_start = bridge->pcie_start + PCI_CAP_PCIE_SIZEOF;
> + } else if (!bridge->pcie_start && bridge->has_pcie) {
> + if (bridge->ssid_start - PCI_BRIDGE_CONF_END >= PCI_CAP_PCIE_SIZEOF)
> + bridge->pcie_start = PCI_BRIDGE_CONF_END;
> + else
> + bridge->pcie_start = bridge->ssid_start + PCI_CAP_SSID_SIZEOF;
> + }
> +
> + bridge->conf.capabilities_pointer = min(bridge->ssid_start, bridge->pcie_start);

>
> if (bridge->conf.capabilities_pointer)
> bridge->conf.status |= cpu_to_le16(PCI_STATUS_CAP_LIST);
> @@ -459,15 +468,17 @@ int pci_bridge_emul_conf_read(struct pci_bridge_emul *bridge, int where,
> read_op = bridge->ops->read_base;
> cfgspace = (__le32 *) &bridge->conf;
> behavior = bridge->pci_regs_behavior;
> - } else if (reg >= PCI_CAP_SSID_START && reg < PCI_CAP_SSID_END && bridge->subsystem_vendor_id) {
> + } else if (reg >= bridge->ssid_start && reg < bridge->ssid_start + PCI_CAP_SSID_SIZEOF &&
> + bridge->subsystem_vendor_id) {
> /* Emulated PCI Bridge Subsystem Vendor ID capability */
> - reg -= PCI_CAP_SSID_START;
> + reg -= bridge->ssid_start;
> read_op = pci_bridge_emul_read_ssid;
> cfgspace = NULL;
> behavior = NULL;
> - } else if (reg >= PCI_CAP_PCIE_START && reg < PCI_CAP_PCIE_END && bridge->has_pcie) {
> + } else if (reg >= bridge->pcie_start && reg < bridge->pcie_start + PCI_CAP_PCIE_SIZEOF &&
> + bridge->has_pcie) {
> /* Our emulated PCIe capability */
> - reg -= PCI_CAP_PCIE_START;
> + reg -= bridge->pcie_start;
> read_op = bridge->ops->read_pcie;
> cfgspace = (__le32 *) &bridge->pcie_conf;
> behavior = bridge->pcie_cap_regs_behavior;
> @@ -538,9 +549,10 @@ int pci_bridge_emul_conf_write(struct pci_bridge_emul *bridge, int where,
> write_op = bridge->ops->write_base;
> cfgspace = (__le32 *) &bridge->conf;
> behavior = bridge->pci_regs_behavior;
> - } else if (reg >= PCI_CAP_PCIE_START && reg < PCI_CAP_PCIE_END && bridge->has_pcie) {
> + } else if (reg >= bridge->pcie_start && reg < bridge->pcie_start + PCI_CAP_PCIE_SIZEOF &&
> + bridge->has_pcie) {
> /* Our emulated PCIe capability */
> - reg -= PCI_CAP_PCIE_START;
> + reg -= bridge->pcie_start;
> write_op = bridge->ops->write_pcie;
> cfgspace = (__le32 *) &bridge->pcie_conf;
> behavior = bridge->pcie_cap_regs_behavior;
> diff --git a/drivers/pci/pci-bridge-emul.h b/drivers/pci/pci-bridge-emul.h
> index 71392b67471d..2a0e59c7f0d9 100644
> --- a/drivers/pci/pci-bridge-emul.h
> +++ b/drivers/pci/pci-bridge-emul.h
> @@ -131,6 +131,8 @@ struct pci_bridge_emul {
> struct pci_bridge_reg_behavior *pci_regs_behavior;
> struct pci_bridge_reg_behavior *pcie_cap_regs_behavior;
> void *data;
> + u8 pcie_start;
> + u8 ssid_start;
> bool has_pcie;
> u16 subsystem_vendor_id;
> u16 subsystem_id;
> --
> 2.20.1
>

Next message: Greg Kroah-Hartman: "[PATCH 4.19 125/287] soundwire: bus_type: fix remove and shutdown support"
Previous message: Greg Kroah-Hartman: "[PATCH 4.19 124/287] clk: qcom: ipq8074: set BRANCH_HALT_DELAY flag for UBI clocks"
In reply to: Bjorn Helgaas: "Re: [PATCH] PCI: pci-bridge-emul: Set position of PCI capabilities to real HW value"
Next in thread: Pali Rohár: "Re: [PATCH] PCI: pci-bridge-emul: Set position of PCI capabilities to real HW value"
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