[PATCH v2 8/9] pci: brcmstb: rework iBAR handling
Neil Armstrong
neil.armstrong at linaro.org
Wed May 6 16:37:28 CEST 2026
On 4/28/26 18:39, Torsten Duwe wrote:
> From: Torsten Duwe <duwe at suse.de>
>
> Rework the setup of inbound PCIe windows: use the convenience functions
> from Linux kernel commit ae6476c6de187 to calculate the BAR offsets and
> factor out the setup code into a separate function.
>
> The Linux kernel first allocates and populates an array of inbound_win[]
> and sets the BARs from it later, while U-Boot does it all on the fly,
> in one go, so the code is not 1:1 comparable.
>
> Signed-off-by: Torsten Duwe <duwe at suse.de>
> Tested-by: Pedro Falcato <pfalcato at suse.de>
>
> ---
> drivers/pci/pcie_brcmstb.c | 150 ++++++++++++++++++++++++++++++++-----
> 1 file changed, 131 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/pci/pcie_brcmstb.c b/drivers/pci/pcie_brcmstb.c
> index 8a25fb04563..05b80a45b50 100644
> --- a/drivers/pci/pcie_brcmstb.c
> +++ b/drivers/pci/pcie_brcmstb.c
> @@ -50,6 +50,29 @@
> #define SSC_STATUS_PLL_LOCK_MASK 0x800
> #define SSC_STATUS_PLL_LOCK_SHIFT 11
>
> +#define PCIE_RC_PL_PHY_CTL_15 0x184c
> +#define PCIE_RC_PL_PHY_CTL_15_DIS_PLL_PD_MASK 0x400000
> +#define PCIE_RC_PL_PHY_CTL_15_PM_CLK_PERIOD_MASK 0xff
> +
> +#define PCIE_MISC_UBUS_CTRL 0x40a4
> +#define PCIE_MISC_UBUS_CTRL_UBUS_PCIE_REPLY_ERR_DIS_MASK BIT(13)
> +#define PCIE_MISC_UBUS_CTRL_UBUS_PCIE_REPLY_DECERR_DIS_MASK BIT(19)
> +#define PCIE_MISC_AXI_READ_ERROR_DATA 0x4170
> +#define PCIE_MISC_UBUS_TIMEOUT 0x40A8
> +#define PCIE_MISC_RC_CONFIG_RETRY_TIMEOUT 0x405c
> +#define PCIE_MISC_RC_BAR4_CONFIG_LO 0x40d4
> +#define PCIE_MISC_RC_BAR4_CONFIG_HI 0x40d8
> +#define PCIE_MISC_UBUS_BAR_CONFIG_REMAP_HI_MASK 0xff
> +#define PCIE_MISC_UBUS_BAR4_CONFIG_REMAP_HI 0x4110
> +#define PCIE_MISC_UBUS_BAR_CONFIG_REMAP_ENABLE 0x1
> +#define PCIE_MISC_UBUS_BAR_CONFIG_REMAP_LO_MASK 0xfffff000
> +#define PCIE_MISC_UBUS_BAR4_CONFIG_REMAP_LO 0x410c
> +
> +#define PCIE_MISC_UBUS_BAR1_CONFIG_REMAP 0x40ac
> +#define PCIE_MISC_UBUS_BAR2_CONFIG_REMAP 0x40b4
> +#define PCIE_MISC_UBUS_BAR2_CONFIG_REMAP_ACCESS_ENABLE_MASK BIT(0)
> +#define MISC_CTRL_PCIE_RCB_MPS_MODE_MASK 0x400
> +
> enum {
> RGR1_SW_INIT_1,
> EXT_CFG_INDEX,
> @@ -437,17 +460,105 @@ static void brcm_pcie_set_outbound_win(struct brcm_pcie *pcie,
> writel(tmp, base + PCIE_MEM_WIN0_LIMIT_HI(win));
> }
>
> +static u32 brcm_bar_reg_offset(int bar)
> +{
> + if (bar <= 3)
> + return PCIE_MISC_RC_BAR1_CONFIG_LO + 8 * (bar - 1);
> + else
> + return PCIE_MISC_RC_BAR4_CONFIG_LO + 8 * (bar - 4);
> +}
> +
> +static u32 brcm_ubus_reg_offset(int bar)
> +{
> + if (bar <= 3)
> + return PCIE_MISC_UBUS_BAR1_CONFIG_REMAP + 8 * (bar - 1);
> + else
> + return PCIE_MISC_UBUS_BAR4_CONFIG_REMAP_LO + 8 * (bar - 4);
> +}
> +
> +/*
> + * Round size up to the next power of two, as required by
> + * brcm_pcie_encode_ibar_size(). If size is already a power of two
> + * fls64(size - 1) still gives the correct result because the hardware
> + * encodes the exponent, not the raw value.
> + */
> +static u64 brcm_ibar_round_size(u64 size)
> +{
> + return 1ULL << fls64(size - 1);
> +}
> +
> +static void brcm_pcie_set_inbound_windows(struct udevice *dev)
> +{
> + struct brcm_pcie *pcie = dev_get_priv(dev);
> + void __iomem *base = pcie->base;
> + bool is_2712 = (pcie->pcie_cfg->type == BCM2712);
> + int i, ibar_no, ret;
> + u32 tmp;
> +
> + ibar_no = 0;
> + /* pre-2712 chips leave the first entry empty */
> + if (pcie->pcie_cfg->type != BCM2712)
> + ibar_no++;
> +
> + /* program inbound windows from OF property "dma-regions" */
> + for (i = 0; i < 7; i++, ibar_no++) {
> + u64 bar_cpu, bar_size, bar_pci;
> + struct pci_region region;
> + int ubus_bar_offset, rc_bar_offset;
> +
> + ret = pci_get_dma_regions(dev, ®ion, i);
> + if (ret) /* no region #i? Then we're done. */
> + break;
> + ubus_bar_offset = brcm_ubus_reg_offset(ibar_no + 1);
> + rc_bar_offset = brcm_bar_reg_offset(ibar_no + 1);
> +
> + bar_pci = region.bus_start;
> + bar_cpu = region.phys_start;
> + bar_size = region.size;
> +
> + if (is_2712) {
> + /* BCM2712: BAR holds raw PCI address; UBUS remap
> + * registers supply the CPU-side translation. */
> + tmp = lower_32_bits(bar_pci);
> + u32p_replace_bits(&tmp, brcm_pcie_encode_ibar_size(bar_size),
> + RC_BAR2_CONFIG_LO_SIZE_MASK);
> + writel(tmp, base + rc_bar_offset);
> + writel(upper_32_bits(bar_pci), base + rc_bar_offset + 4);
> +
> + tmp = lower_32_bits(bar_cpu) &
> + PCIE_MISC_UBUS_BAR_CONFIG_REMAP_LO_MASK;
> + tmp |= PCIE_MISC_UBUS_BAR_CONFIG_REMAP_ENABLE;
> + writel(tmp, base + ubus_bar_offset);
> +
> + tmp = upper_32_bits(bar_cpu) &
> + PCIE_MISC_UBUS_BAR_CONFIG_REMAP_HI_MASK;
> + writel(tmp, base + ubus_bar_offset + 4);
> + } else {
> + /* Pre-BCM2712 (e.g. BCM2711 / RPi4): the BAR config
> + * register holds the offset (bus_start - phys_start),
> + * not the raw PCI address. The size must be rounded
> + * up to the next power of two before encoding. */
> + u64 bar_offset = bar_pci - bar_cpu;
> + u64 bar_size_po2 = brcm_ibar_round_size(bar_size);
> +
> + tmp = lower_32_bits(bar_offset);
> + u32p_replace_bits(&tmp, brcm_pcie_encode_ibar_size(bar_size_po2),
> + RC_BAR2_CONFIG_LO_SIZE_MASK);
> + writel(tmp, base + rc_bar_offset);
> + writel(upper_32_bits(bar_offset), base + rc_bar_offset + 4);
> + /* UBUS remap registers are not used on pre-2712 hardware. */
> + }
> + }
> +}
> +
> static int brcm_pcie_probe(struct udevice *dev)
> {
> struct udevice *ctlr = pci_get_controller(dev);
> struct pci_controller *hose = dev_get_uclass_priv(ctlr);
> struct brcm_pcie *pcie = dev_get_priv(dev);
> void __iomem *base = pcie->base;
> - struct pci_region region;
> bool ssc_good = false;
> int num_out_wins = 0;
> - u64 rc_bar2_offset, rc_bar2_size;
> - unsigned int scb_size_val;
> int i, ret;
> u16 nlw, cls, lnksta;
> u32 tmp;
> @@ -488,23 +599,22 @@ static int brcm_pcie_probe(struct udevice *dev)
> MISC_CTRL_CFG_READ_UR_MODE_MASK |
> MISC_CTRL_MAX_BURST_SIZE_128);
>
> - pci_get_dma_regions(dev, ®ion, 0);
> - rc_bar2_offset = region.bus_start - region.phys_start;
> - rc_bar2_size = 1ULL << fls64(region.size - 1);
> -
> - tmp = lower_32_bits(rc_bar2_offset);
> - u32p_replace_bits(&tmp, brcm_pcie_encode_ibar_size(rc_bar2_size),
> - RC_BAR2_CONFIG_LO_SIZE_MASK);
> - writel(tmp, base + PCIE_MISC_RC_BAR2_CONFIG_LO);
> - writel(upper_32_bits(rc_bar2_offset),
> - base + PCIE_MISC_RC_BAR2_CONFIG_HI);
> -
> - scb_size_val = rc_bar2_size ?
> - ilog2(rc_bar2_size) - 15 : 0xf; /* 0xf is 1GB */
> -
> tmp = readl(base + PCIE_MISC_MISC_CTRL);
> - u32p_replace_bits(&tmp, scb_size_val,
> - MISC_CTRL_SCB0_SIZE_MASK);
> + if (pcie->pcie_cfg->type == BCM2712) {
> + /* BCM2712: fixed 32GB SCB0 window */
> + u32p_replace_bits(&tmp, 20, MISC_CTRL_SCB0_SIZE_MASK);
> + } else {
> + /* Pre-BCM2712: size SCB0 to match the actual DMA region.
> + * rc_bar2_size must be a power of two; ilog2(size) - 15
> + * gives the hardware encoding (e.g. 1GB -> 15). */
> + struct pci_region region;
> + u64 rc_bar2_size;
> +
> + pci_get_dma_regions(dev, ®ion, 0);
> + rc_bar2_size = brcm_ibar_round_size(region.size);
> + u32p_replace_bits(&tmp, rc_bar2_size ? ilog2(rc_bar2_size) - 15 : 0xf,
> + MISC_CTRL_SCB0_SIZE_MASK);
> + }
> writel(tmp, base + PCIE_MISC_MISC_CTRL);
>
> /* Disable the PCIe->GISB memory window (RC_BAR1) */
> @@ -521,6 +631,8 @@ static int brcm_pcie_probe(struct udevice *dev)
> /* Clear any interrupts we find on boot */
> writel(0xffffffff, base + PCIE_MSI_INTR2_CLR);
>
> + brcm_pcie_set_inbound_windows(dev);
> +
> if (pcie->gen)
> brcm_pcie_set_gen(pcie, pcie->gen);
>
Looks fine
Reviewed-by: Neil Armstrong <neil.armstrong at linaro.org>
Thanks,
Neil
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