Re: [PATCH v6 4/4] PCI: designware: Add iATU Unroll feature

From: Tim Harvey
Date: Tue Nov 15 2016 - 19:22:29 EST

On Wed, Aug 17, 2016 at 1:00 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote:
> From: Joao Pinto <Joao.Pinto@xxxxxxxxxxxx>
>
> Add support for the new iATU Unroll mechanism that will be used from Core
> version 4.80. The new Cores can support either iATU Unroll or the "old"
> iATU method, now called Legacy Mode. The driver is perfectly capable of
> performing well for both.
>
> [bhelgaas: split ATU enable timeout to separate patch]
> Signed-off-by: Joao Pinto <jpinto@xxxxxxxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
> ---
> drivers/pci/host/pcie-designware.c | 97 ++++++++++++++++++++++++++++++++----
> drivers/pci/host/pcie-designware.h | 1
> 2 files changed, 87 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c
> index 947fac3..e489b18 100644
> --- a/drivers/pci/host/pcie-designware.c
> +++ b/drivers/pci/host/pcie-designware.c
> @@ -80,6 +80,21 @@
> #define PCIE_ATU_FUNC(x) (((x) & 0x7) << 16)
> #define PCIE_ATU_UPPER_TARGET 0x91C
>
> +/*
> + * iATU Unroll-specific register definitions
> + * From 4.80 core version the address translation will be made by unroll
> + */
> +#define PCIE_ATU_UNR_REGION_CTRL1 0x00
> +#define PCIE_ATU_UNR_REGION_CTRL2 0x04
> +#define PCIE_ATU_UNR_LOWER_BASE 0x08
> +#define PCIE_ATU_UNR_UPPER_BASE 0x0C
> +#define PCIE_ATU_UNR_LIMIT 0x10
> +#define PCIE_ATU_UNR_LOWER_TARGET 0x14
> +#define PCIE_ATU_UNR_UPPER_TARGET 0x18
> +
> +/* Register address builder */
> +#define PCIE_GET_ATU_OUTB_UNR_REG_OFFSET(region) ((0x3 << 20) | (region << 9)
> +
> /* PCIe Port Logic registers */
> #define PLR_OFFSET 0x700
> #define PCIE_PHY_DEBUG_R1 (PLR_OFFSET + 0x2c)
> @@ -141,6 +156,27 @@ static inline void dw_pcie_writel_rc(struct pcie_port *pp, u32 val, u32 reg)
> writel(val, pp->dbi_base + reg);
> }
>
> +static inline u32 dw_pcie_readl_unroll(struct pcie_port *pp, u32 index, u32 reg)
> +{
> + u32 offset = PCIE_GET_ATU_OUTB_UNR_REG_OFFSET(index);
> +
> + if (pp->ops->readl_rc)
> + return pp->ops->readl_rc(pp, pp->dbi_base + offset + reg);
> +
> + return readl(pp->dbi_base + offset + reg);
> +}
> +
> +static inline void dw_pcie_writel_unroll(struct pcie_port *pp, u32 index,
> + u32 val, u32 reg)
> +{
> + u32 offset = PCIE_GET_ATU_OUTB_UNR_REG_OFFSET(index);
> +
> + if (pp->ops->writel_rc)
> + pp->ops->writel_rc(pp, val, pp->dbi_base + offset + reg);
> + else
> + writel(val, pp->dbi_base + offset + reg);
> +}
> +
> static int dw_pcie_rd_own_conf(struct pcie_port *pp, int where, int size,
> u32 *val)
> {
> @@ -164,23 +200,49 @@ static void dw_pcie_prog_outbound_atu(struct pcie_port *pp, int index,
> {
> u32 retries, val;
>
> - dw_pcie_writel_rc(pp, PCIE_ATU_REGION_OUTBOUND | index,
> - PCIE_ATU_VIEWPORT);
> - dw_pcie_writel_rc(pp, lower_32_bits(cpu_addr), PCIE_ATU_LOWER_BASE);
> - dw_pcie_writel_rc(pp, upper_32_bits(cpu_addr), PCIE_ATU_UPPER_BASE);
> - dw_pcie_writel_rc(pp, lower_32_bits(cpu_addr + size - 1),
> - PCIE_ATU_LIMIT);
> - dw_pcie_writel_rc(pp, lower_32_bits(pci_addr), PCIE_ATU_LOWER_TARGET);
> - dw_pcie_writel_rc(pp, upper_32_bits(pci_addr), PCIE_ATU_UPPER_TARGET);
> - dw_pcie_writel_rc(pp, type, PCIE_ATU_CR1);
> - dw_pcie_writel_rc(pp, PCIE_ATU_ENABLE, PCIE_ATU_CR2);
> + if (pp->iatu_unroll_enabled) {
> + dw_pcie_writel_unroll(pp, index,
> + lower_32_bits(cpu_addr), PCIE_ATU_UNR_LOWER_BASE);
> + dw_pcie_writel_unroll(pp, index,
> + upper_32_bits(cpu_addr), PCIE_ATU_UNR_UPPER_BASE);
> + dw_pcie_writel_unroll(pp, index,
> + lower_32_bits(cpu_addr + size - 1), PCIE_ATU_UNR_LIMIT);
> + dw_pcie_writel_unroll(pp, index,
> + lower_32_bits(pci_addr), PCIE_ATU_UNR_LOWER_TARGET);
> + dw_pcie_writel_unroll(pp, index,
> + upper_32_bits(pci_addr), PCIE_ATU_UNR_UPPER_TARGET);
> + dw_pcie_writel_unroll(pp, index,
> + type, PCIE_ATU_UNR_REGION_CTRL1);
> + dw_pcie_writel_unroll(pp, index,
> + PCIE_ATU_ENABLE, PCIE_ATU_UNR_REGION_CTRL2);
> + } else {
> + dw_pcie_writel_rc(pp, PCIE_ATU_REGION_OUTBOUND | index,
> + PCIE_ATU_VIEWPORT);
> + dw_pcie_writel_rc(pp, lower_32_bits(cpu_addr),
> + PCIE_ATU_LOWER_BASE);
> + dw_pcie_writel_rc(pp, upper_32_bits(cpu_addr),
> + PCIE_ATU_UPPER_BASE);
> + dw_pcie_writel_rc(pp, lower_32_bits(cpu_addr + size - 1),
> + PCIE_ATU_LIMIT);
> + dw_pcie_writel_rc(pp, lower_32_bits(pci_addr),
> + PCIE_ATU_LOWER_TARGET);
> + dw_pcie_writel_rc(pp, upper_32_bits(pci_addr),
> + PCIE_ATU_UPPER_TARGET);
> + dw_pcie_writel_rc(pp, type, PCIE_ATU_CR1);
> + dw_pcie_writel_rc(pp, PCIE_ATU_ENABLE, PCIE_ATU_CR2);
> + }
>
> /*
> * Make sure ATU enable takes effect before any subsequent config
> * and I/O accesses.
> */
> for (retries = 0; retries < LINK_WAIT_MAX_IATU_RETRIES; retries++) {
> - val = dw_pcie_readl_rc(pp, PCIE_ATU_CR2);
> + if (pp->iatu_unroll_enabled)
> + val = dw_pcie_readl_unroll(pp, index,
> + PCIE_ATU_UNR_REGION_CTRL2);
> + else
> + val = dw_pcie_readl_rc(pp, PCIE_ATU_CR2);
> +
> if (val == PCIE_ATU_ENABLE)
> return;
>
> @@ -445,6 +507,17 @@ static const struct irq_domain_ops msi_domain_ops = {
> .map = dw_pcie_msi_map,
> };
>
> +static u8 dw_pcie_iatu_unroll_enabled(struct pcie_port *pp)
> +{
> + u32 val = 0;
> +
> + dw_pcie_readl_rc(pp, PCIE_ATU_VIEWPORT, &val);
> + if (val == 0xffffffff)
> + return 1;
> +
> + return 0;
> +}
> +
> int dw_pcie_host_init(struct pcie_port *pp)
> {
> struct device_node *np = pp->dev->of_node;
> @@ -561,6 +634,8 @@ int dw_pcie_host_init(struct pcie_port *pp)
> }
> }
>
> + pp->iatu_unroll_enabled = dw_pcie_iatu_unroll_enabled(pp);
> +
> if (pp->ops->host_init)
> pp->ops->host_init(pp);
>
> diff --git a/drivers/pci/host/pcie-designware.h b/drivers/pci/host/pcie-designware.h
> index 285e1ed..e74cc4a 100644
> --- a/drivers/pci/host/pcie-designware.h
> +++ b/drivers/pci/host/pcie-designware.h
> @@ -48,6 +48,7 @@ struct pcie_port {
> int msi_irq;
> struct irq_domain *irq_domain;
> unsigned long msi_data;
> + u8 iatu_unroll_enabled;
> DECLARE_BITMAP(msi_irq_in_use, MAX_MSI_IRQS);
> };
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html

Bjorn / Joao,

This patch (from commit a0601a47053714eecec726aea5ebcd829f817497) is
causing a kernel regression in 4.9. I can no longer boot the kernel on
boards that have a PCIe switch downstream from the IMX6 (ie many of
the Gateworks Ventana boards) unless PCI is enabled in the bootloader
(which is not recommended as that causes PCI link in the kernel to
occasionally fail).

Regards,

Tim