Re: [PATCH v3 5/5] PCI: altera: Add Agilex support

Manivannan Sadhasivam
2025-01-16T17:05:50Z

On Wed, Jan 08, 2025 at 10:59:09AM -0600, Matthew Gerlach wrote:
> From: "D M, Sharath Kumar" <sharath.kumar.d.m@intel.com>
>
> Add PCIe root port controller support Agilex family of chips.
>

Please add more info about the PCIe controller in description. Like speed,
lanes, IP revision etc... Also, you are introducing ep_{read/write}_cfg()
callbacks, so they should also be described here.

> Signed-off-by: D M, Sharath Kumar <sharath.kumar.d.m@intel.com>
> Signed-off-by: Matthew Gerlach <matthew.gerlach@linux.intel.com>
> ---
> v3:
> - Remove accepted patches from patch set.
>
> v2:
> - Match historical style of subject.
> - Remove unrelated changes.
> - Fix indentation.
> ---
> drivers/pci/controller/pcie-altera.c | 246 ++++++++++++++++++++++++++-
> 1 file changed, 237 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/pci/controller/pcie-altera.c b/drivers/pci/controller/pcie-altera.c
> index eb55a7f8573a..da4ae21d661d 100644
> --- a/drivers/pci/controller/pcie-altera.c
> +++ b/drivers/pci/controller/pcie-altera.c
> @@ -77,9 +77,19 @@
> #define S10_TLP_FMTTYPE_CFGWR0 0x45
> #define S10_TLP_FMTTYPE_CFGWR1 0x44
>
> +#define AGLX_RP_CFG_ADDR(pcie, reg) (((pcie)->hip_base) + (reg))
> +#define AGLX_RP_SECONDARY(pcie) \
> + readb(AGLX_RP_CFG_ADDR(pcie, PCI_SECONDARY_BUS))
> +
> +#define AGLX_BDF_REG 0x00002004
> +#define AGLX_ROOT_PORT_IRQ_STATUS 0x14c
> +#define AGLX_ROOT_PORT_IRQ_ENABLE 0x150
> +#define CFG_AER BIT(4)
> +
> enum altera_pcie_version {
> ALTERA_PCIE_V1 = 0,
> ALTERA_PCIE_V2,
> + ALTERA_PCIE_V3,
> };
>
> struct altera_pcie {
> @@ -102,6 +112,11 @@ struct altera_pcie_ops {
> int size, u32 *value);
> int (*rp_write_cfg)(struct altera_pcie *pcie, u8 busno,
> int where, int size, u32 value);
> + int (*ep_read_cfg)(struct altera_pcie *pcie, u8 busno,
> + unsigned int devfn, int where, int size, u32 *value);
> + int (*ep_write_cfg)(struct altera_pcie *pcie, u8 busno,
> + unsigned int devfn, int where, int size, u32 value);
> + void (*rp_isr)(struct irq_desc *desc);
> };
>
> struct altera_pcie_data {
> @@ -112,6 +127,9 @@ struct altera_pcie_data {
> u32 cfgrd1;
> u32 cfgwr0;
> u32 cfgwr1;
> + u32 port_conf_offset;
> + u32 port_irq_status_offset;
> + u32 port_irq_enable_offset;
> };
>
> struct tlp_rp_regpair_t {
> @@ -131,6 +149,28 @@ static inline u32 cra_readl(struct altera_pcie *pcie, const u32 reg)
> return readl_relaxed(pcie->cra_base + reg);
> }
>
> +static inline void cra_writew(struct altera_pcie *pcie, const u32 value,
> + const u32 reg)

No need to add inline keyword to .c files. Compiler will inline the function
anyway if needed.

> +{
> + writew_relaxed(value, pcie->cra_base + reg);
> +}
> +
> +static inline u32 cra_readw(struct altera_pcie *pcie, const u32 reg)
> +{
> + return readw_relaxed(pcie->cra_base + reg);
> +}
> +
> +static inline void cra_writeb(struct altera_pcie *pcie, const u32 value,
> + const u32 reg)
> +{
> + writeb_relaxed(value, pcie->cra_base + reg);
> +}
> +
> +static inline u32 cra_readb(struct altera_pcie *pcie, const u32 reg)
> +{
> + return readb_relaxed(pcie->cra_base + reg);
> +}
> +
> static bool altera_pcie_link_up(struct altera_pcie *pcie)
> {
> return !!((cra_readl(pcie, RP_LTSSM) & RP_LTSSM_MASK) == LTSSM_L0);
> @@ -145,6 +185,15 @@ static bool s10_altera_pcie_link_up(struct altera_pcie *pcie)
> return !!(readw(addr) & PCI_EXP_LNKSTA_DLLLA);
> }
>
> +static bool aglx_altera_pcie_link_up(struct altera_pcie *pcie)
> +{
> + void __iomem *addr = AGLX_RP_CFG_ADDR(pcie,
> + pcie->pcie_data->cap_offset +
> + PCI_EXP_LNKSTA);
> +
> + return !!(readw(addr) & PCI_EXP_LNKSTA_DLLLA);

Why this can't be readw_relaxed()?

> +}
> +
> /*
> * Altera PCIe port uses BAR0 of RC's configuration space as the translation
> * from PCI bus to native BUS. Entire DDR region is mapped into PCIe space
> @@ -425,6 +474,103 @@ static int s10_rp_write_cfg(struct altera_pcie *pcie, u8 busno,
> return PCIBIOS_SUCCESSFUL;
> }
>
> +static int aglx_rp_read_cfg(struct altera_pcie *pcie, int where,
> + int size, u32 *value)
> +{
> + void __iomem *addr = AGLX_RP_CFG_ADDR(pcie, where);
> +
> + switch (size) {
> + case 1:
> + *value = readb(addr);

Same question as above. Why the relaxed variant is not used here?

> + break;
> + case 2:
> + *value = readw(addr);
> + break;
> + default:
> + *value = readl(addr);
> + break;
> + }
> +
> + /* interrupt pin not programmed in hardware, set to INTA */
> + if (where == PCI_INTERRUPT_PIN && size == 1 && !(*value))
> + *value = 0x01;
> + else if (where == PCI_INTERRUPT_LINE && !(*value & 0xff00))
> + *value |= 0x0100;
> +
> + return PCIBIOS_SUCCESSFUL;
> +}
> +
> +static int aglx_rp_write_cfg(struct altera_pcie *pcie, u8 busno,
> + int where, int size, u32 value)
> +{
> + void __iomem *addr = AGLX_RP_CFG_ADDR(pcie, where);
> +
> + switch (size) {
> + case 1:
> + writeb(value, addr);
> + break;
> + case 2:
> + writew(value, addr);
> + break;
> + default:
> + writel(value, addr);
> + break;
> + }
> +
> + /*
> + * Monitor changes to PCI_PRIMARY_BUS register on root port
> + * and update local copy of root bus number accordingly.
> + */
> + if (busno == pcie->root_bus_nr && where == PCI_PRIMARY_BUS)
> + pcie->root_bus_nr = value & 0xff;
> +
> + return PCIBIOS_SUCCESSFUL;
> +}
> +
> +static int aglx_ep_write_cfg(struct altera_pcie *pcie, u8 busno,
> + unsigned int devfn, int where, int size, u32 value)
> +{
> + cra_writel(pcie, ((busno << 8) | devfn), AGLX_BDF_REG);
> + if (busno > AGLX_RP_SECONDARY(pcie))
> + where |= (1 << 12); /* type 1 */

Can you use macro definition for this?

> +
> + switch (size) {
> + case 1:
> + cra_writeb(pcie, value, where);
> + break;
> + case 2:
> + cra_writew(pcie, value, where);
> + break;
> + default:
> + cra_writel(pcie, value, where);
> + break;
> + }
> +
> + return PCIBIOS_SUCCESSFUL;
> +}
> +
> +static int aglx_ep_read_cfg(struct altera_pcie *pcie, u8 busno,
> + unsigned int devfn, int where, int size, u32 *value)
> +{
> + cra_writel(pcie, ((busno << 8) | devfn), AGLX_BDF_REG);
> + if (busno > AGLX_RP_SECONDARY(pcie))
> + where |= (1 << 12); /* type 1 */

Same here.

> +
> + switch (size) {
> + case 1:
> + *value = cra_readb(pcie, where);
> + break;
> + case 2:
> + *value = cra_readw(pcie, where);
> + break;
> + default:
> + *value = cra_readl(pcie, where);
> + break;
> + }
> +
> + return PCIBIOS_SUCCESSFUL;
> +}
> +
> static int _altera_pcie_cfg_read(struct altera_pcie *pcie, u8 busno,
> unsigned int devfn, int where, int size,
> u32 *value)
> @@ -437,6 +583,10 @@ static int _altera_pcie_cfg_read(struct altera_pcie *pcie, u8 busno,
> return pcie->pcie_data->ops->rp_read_cfg(pcie, where,
> size, value);
>
> + if (pcie->pcie_data->ops->ep_read_cfg)
> + return pcie->pcie_data->ops->ep_read_cfg(pcie, busno, devfn,
> + where, size, value);

Why do you need to call both rp_read_cfg() and ep_read_cfg()? This looks wrong.

> +
> switch (size) {
> case 1:
> byte_en = 1 << (where & 3);
> @@ -481,6 +631,10 @@ static int _altera_pcie_cfg_write(struct altera_pcie *pcie, u8 busno,
> return pcie->pcie_data->ops->rp_write_cfg(pcie, busno,
> where, size, value);
>
> + if (pcie->pcie_data->ops->ep_write_cfg)
> + return pcie->pcie_data->ops->ep_write_cfg(pcie, busno, devfn,
> + where, size, value);
> +
> switch (size) {
> case 1:
> data32 = (value & 0xff) << shift;
> @@ -659,7 +813,30 @@ static void altera_pcie_isr(struct irq_desc *desc)
> dev_err_ratelimited(dev, "unexpected IRQ, INT%d\n", bit);
> }
> }
> + chained_irq_exit(chip, desc);
> +}
> +
> +static void aglx_isr(struct irq_desc *desc)
> +{
> + struct irq_chip *chip = irq_desc_get_chip(desc);
> + struct altera_pcie *pcie;
> + struct device *dev;
> + u32 status;
> + int ret;
> +
> + chained_irq_enter(chip, desc);
> + pcie = irq_desc_get_handler_data(desc);
> + dev = &pcie->pdev->dev;
>
> + status = readl(pcie->hip_base + pcie->pcie_data->port_conf_offset +
> + pcie->pcie_data->port_irq_status_offset);
> + if (status & CFG_AER) {
> + ret = generic_handle_domain_irq(pcie->irq_domain, 0);
> + if (ret)
> + dev_err_ratelimited(dev, "unexpected IRQ\n");

It'd be good to print the IRQ number in error log.

> + }
> + writel(CFG_AER, (pcie->hip_base + pcie->pcie_data->port_conf_offset +
> + pcie->pcie_data->port_irq_status_offset));

You should clear the IRQ before handling it.

> chained_irq_exit(chip, desc);
> }
>

[...]

> - /* clear all interrupts */
> - cra_writel(pcie, P2A_INT_STS_ALL, P2A_INT_STATUS);
> - /* enable all interrupts */
> - cra_writel(pcie, P2A_INT_ENA_ALL, P2A_INT_ENABLE);
> - altera_pcie_host_init(pcie);
> + if (pcie->pcie_data->version == ALTERA_PCIE_V1 ||
> + pcie->pcie_data->version == ALTERA_PCIE_V2) {
> + /* clear all interrupts */
> + cra_writel(pcie, P2A_INT_STS_ALL, P2A_INT_STATUS);
> + /* enable all interrupts */
> + cra_writel(pcie, P2A_INT_ENA_ALL, P2A_INT_ENABLE);
> + altera_pcie_host_init(pcie);
> + } else if (pcie->pcie_data->version == ALTERA_PCIE_V3) {
> + writel(CFG_AER,
> + pcie->hip_base + pcie->pcie_data->port_conf_offset +
> + pcie->pcie_data->port_irq_enable_offset);

Why altera_pcie_host_init() is not called for ALTERA_PCIE_V3?

- Mani

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