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PCI: aardvark: Implement emulated root PCI bridge config space
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The PCI controller in the Marvell Armada 3720 does not implement a
software-accessible root port PCI bridge configuration space. This
causes a number of problems when using PCIe switches or when the Max
Payload size needs to be aligned between the root complex and the
endpoint.

Implementing an emulated root PCI bridge, like is already done in the
pci-mvebu driver for older Marvell platforms allows to solve those
issues, and also to support features such as ASR, PME, VC, HP.

Signed-off-by: Zachary Zhang <zhangzg@marvell.com>
[Thomas: convert to the common emulated PCI bridge logic.]
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
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Zachary Zhang authored and Lorenzo Pieralisi committed Oct 18, 2018
1 parent 1f08673 commit 8a3ebd8
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Showing 2 changed files with 127 additions and 3 deletions.
1 change: 1 addition & 0 deletions drivers/pci/controller/Kconfig
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,7 @@ config PCI_AARDVARK
depends on (ARCH_MVEBU && ARM64) || COMPILE_TEST
depends on OF
depends on PCI_MSI_IRQ_DOMAIN
select PCI_BRIDGE_EMUL
help
Add support for Aardvark 64bit PCIe Host Controller. This
controller is part of the South Bridge of the Marvel Armada
Expand Down
129 changes: 126 additions & 3 deletions drivers/pci/controller/pci-aardvark.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,12 +20,16 @@
#include <linux/of_pci.h>

#include "../pci.h"
#include "../pci-bridge-emul.h"

/* PCIe core registers */
#define PCIE_CORE_DEV_ID_REG 0x0
#define PCIE_CORE_CMD_STATUS_REG 0x4
#define PCIE_CORE_CMD_IO_ACCESS_EN BIT(0)
#define PCIE_CORE_CMD_MEM_ACCESS_EN BIT(1)
#define PCIE_CORE_CMD_MEM_IO_REQ_EN BIT(2)
#define PCIE_CORE_DEV_REV_REG 0x8
#define PCIE_CORE_PCIEXP_CAP 0xc0
#define PCIE_CORE_DEV_CTRL_STATS_REG 0xc8
#define PCIE_CORE_DEV_CTRL_STATS_RELAX_ORDER_DISABLE (0 << 4)
#define PCIE_CORE_DEV_CTRL_STATS_MAX_PAYLOAD_SZ_SHIFT 5
Expand All @@ -41,7 +45,10 @@
#define PCIE_CORE_ERR_CAPCTL_ECRC_CHK_TX_EN BIT(6)
#define PCIE_CORE_ERR_CAPCTL_ECRC_CHCK BIT(7)
#define PCIE_CORE_ERR_CAPCTL_ECRC_CHCK_RCV BIT(8)

#define PCIE_CORE_INT_A_ASSERT_ENABLE 1
#define PCIE_CORE_INT_B_ASSERT_ENABLE 2
#define PCIE_CORE_INT_C_ASSERT_ENABLE 3
#define PCIE_CORE_INT_D_ASSERT_ENABLE 4
/* PIO registers base address and register offsets */
#define PIO_BASE_ADDR 0x4000
#define PIO_CTRL (PIO_BASE_ADDR + 0x0)
Expand Down Expand Up @@ -93,7 +100,9 @@
#define PCIE_CORE_CTRL2_STRICT_ORDER_ENABLE BIT(5)
#define PCIE_CORE_CTRL2_OB_WIN_ENABLE BIT(6)
#define PCIE_CORE_CTRL2_MSI_ENABLE BIT(10)
#define PCIE_MSG_LOG_REG (CONTROL_BASE_ADDR + 0x30)
#define PCIE_ISR0_REG (CONTROL_BASE_ADDR + 0x40)
#define PCIE_MSG_PM_PME_MASK BIT(7)
#define PCIE_ISR0_MASK_REG (CONTROL_BASE_ADDR + 0x44)
#define PCIE_ISR0_MSI_INT_PENDING BIT(24)
#define PCIE_ISR0_INTX_ASSERT(val) BIT(16 + (val))
Expand Down Expand Up @@ -189,6 +198,7 @@ struct advk_pcie {
struct mutex msi_used_lock;
u16 msi_msg;
int root_bus_nr;
struct pci_bridge_emul bridge;
};

static inline void advk_writel(struct advk_pcie *pcie, u32 val, u64 reg)
Expand Down Expand Up @@ -390,6 +400,109 @@ static int advk_pcie_wait_pio(struct advk_pcie *pcie)
return -ETIMEDOUT;
}


static pci_bridge_emul_read_status_t
advk_pci_bridge_emul_pcie_conf_read(struct pci_bridge_emul *bridge,
int reg, u32 *value)
{
struct advk_pcie *pcie = bridge->data;


switch (reg) {
case PCI_EXP_SLTCTL:
*value = PCI_EXP_SLTSTA_PDS << 16;
return PCI_BRIDGE_EMUL_HANDLED;

case PCI_EXP_RTCTL: {
u32 val = advk_readl(pcie, PCIE_ISR0_MASK_REG);
*value = (val & PCIE_MSG_PM_PME_MASK) ? PCI_EXP_RTCTL_PMEIE : 0;
return PCI_BRIDGE_EMUL_HANDLED;
}

case PCI_EXP_RTSTA: {
u32 isr0 = advk_readl(pcie, PCIE_ISR0_REG);
u32 msglog = advk_readl(pcie, PCIE_MSG_LOG_REG);
*value = (isr0 & PCIE_MSG_PM_PME_MASK) << 16 | (msglog >> 16);
return PCI_BRIDGE_EMUL_HANDLED;
}

case PCI_CAP_LIST_ID:
case PCI_EXP_DEVCAP:
case PCI_EXP_DEVCTL:
case PCI_EXP_LNKCAP:
case PCI_EXP_LNKCTL:
*value = advk_readl(pcie, PCIE_CORE_PCIEXP_CAP + reg);
return PCI_BRIDGE_EMUL_HANDLED;
default:
return PCI_BRIDGE_EMUL_NOT_HANDLED;
}

}

static void
advk_pci_bridge_emul_pcie_conf_write(struct pci_bridge_emul *bridge,
int reg, u32 old, u32 new, u32 mask)
{
struct advk_pcie *pcie = bridge->data;

switch (reg) {
case PCI_EXP_DEVCTL:
case PCI_EXP_LNKCTL:
advk_writel(pcie, new, PCIE_CORE_PCIEXP_CAP + reg);
break;

case PCI_EXP_RTCTL:
new = (new & PCI_EXP_RTCTL_PMEIE) << 3;
advk_writel(pcie, new, PCIE_ISR0_MASK_REG);
break;

case PCI_EXP_RTSTA:
new = (new & PCI_EXP_RTSTA_PME) >> 9;
advk_writel(pcie, new, PCIE_ISR0_REG);
break;

default:
break;
}
}

struct pci_bridge_emul_ops advk_pci_bridge_emul_ops = {
.read_pcie = advk_pci_bridge_emul_pcie_conf_read,
.write_pcie = advk_pci_bridge_emul_pcie_conf_write,
};

/*
* Initialize the configuration space of the PCI-to-PCI bridge
* associated with the given PCIe interface.
*/
static void advk_sw_pci_bridge_init(struct advk_pcie *pcie)
{
struct pci_bridge_emul *bridge = &pcie->bridge;

bridge->conf.vendor = advk_readl(pcie, PCIE_CORE_DEV_ID_REG) & 0xffff;
bridge->conf.device = advk_readl(pcie, PCIE_CORE_DEV_ID_REG) >> 16;
bridge->conf.class_revision =
advk_readl(pcie, PCIE_CORE_DEV_REV_REG) & 0xff;

/* Support 32 bits I/O addressing */
bridge->conf.iobase = PCI_IO_RANGE_TYPE_32;
bridge->conf.iolimit = PCI_IO_RANGE_TYPE_32;

/* Support 64 bits memory pref */
bridge->conf.pref_mem_base = PCI_PREF_RANGE_TYPE_64;
bridge->conf.pref_mem_limit = PCI_PREF_RANGE_TYPE_64;

/* Support interrupt A for MSI feature */
bridge->conf.intpin = PCIE_CORE_INT_A_ASSERT_ENABLE;

bridge->has_pcie = true;
bridge->data = pcie;
bridge->ops = &advk_pci_bridge_emul_ops;

pci_bridge_emul_init(bridge);

}

static bool advk_pcie_valid_device(struct advk_pcie *pcie, struct pci_bus *bus,
int devfn)
{
Expand All @@ -411,14 +524,18 @@ static int advk_pcie_rd_conf(struct pci_bus *bus, u32 devfn,
return PCIBIOS_DEVICE_NOT_FOUND;
}

if (bus->number == pcie->root_bus_nr)
return pci_bridge_emul_conf_read(&pcie->bridge, where,
size, val);

/* Start PIO */
advk_writel(pcie, 0, PIO_START);
advk_writel(pcie, 1, PIO_ISR);

/* Program the control register */
reg = advk_readl(pcie, PIO_CTRL);
reg &= ~PIO_CTRL_TYPE_MASK;
if (bus->number == pcie->root_bus_nr)
if (bus->primary == pcie->root_bus_nr)
reg |= PCIE_CONFIG_RD_TYPE0;
else
reg |= PCIE_CONFIG_RD_TYPE1;
Expand Down Expand Up @@ -463,6 +580,10 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
if (!advk_pcie_valid_device(pcie, bus, devfn))
return PCIBIOS_DEVICE_NOT_FOUND;

if (bus->number == pcie->root_bus_nr)
return pci_bridge_emul_conf_write(&pcie->bridge, where,
size, val);

if (where % size)
return PCIBIOS_SET_FAILED;

Expand All @@ -473,7 +594,7 @@ static int advk_pcie_wr_conf(struct pci_bus *bus, u32 devfn,
/* Program the control register */
reg = advk_readl(pcie, PIO_CTRL);
reg &= ~PIO_CTRL_TYPE_MASK;
if (bus->number == pcie->root_bus_nr)
if (bus->primary == pcie->root_bus_nr)
reg |= PCIE_CONFIG_WR_TYPE0;
else
reg |= PCIE_CONFIG_WR_TYPE1;
Expand Down Expand Up @@ -875,6 +996,8 @@ static int advk_pcie_probe(struct platform_device *pdev)

advk_pcie_setup_hw(pcie);

advk_sw_pci_bridge_init(pcie);

ret = advk_pcie_init_irq_domain(pcie);
if (ret) {
dev_err(dev, "Failed to initialize irq\n");
Expand Down

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