Message-ID: <CA+-6iNyQ09BESbdCwY1x4yUOLmAHKFBU3-9TO_ST+2GkOEEAng@mail.gmail.com>
Date: Thu, 25 Jul 2024 16:29:56 -0400
From: Jim Quinlan <james.quinlan@...adcom.com>
To: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
Cc: linux-pci@...r.kernel.org, Nicolas Saenz Julienne <nsaenz@...nel.org>, 
	Bjorn Helgaas <bhelgaas@...gle.com>, Lorenzo Pieralisi <lorenzo.pieralisi@....com>, 
	Cyril Brulebois <kibi@...ian.org>, Stanimir Varbanov <svarbanov@...e.de>, 
	Krzysztof Kozlowski <krzk@...nel.org>, bcm-kernel-feedback-list@...adcom.com, 
	jim2101024@...il.com, Florian Fainelli <florian.fainelli@...adcom.com>, 
	Lorenzo Pieralisi <lpieralisi@...nel.org>, Krzysztof Wilczyński <kw@...ux.com>, 
	Rob Herring <robh@...nel.org>, 
	"moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" <linux-rpi-kernel@...ts.infradead.org>, 
	"moderated list:BROADCOM BCM2711/BCM2835 ARM ARCHITECTURE" <linux-arm-kernel@...ts.infradead.org>, 
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 09/12] PCI: brcmstb: Refactor for chips with many
 regular inbound BARs

On Thu, Jul 25, 2024 at 12:53 AM Manivannan Sadhasivam
<manivannan.sadhasivam@...aro.org> wrote:
>
> On Tue, Jul 16, 2024 at 05:31:24PM -0400, Jim Quinlan wrote:
> > Previously, our chips provided three inbound "BARS" with fixed purposes:
> > the first was for mapping SoC internal registers, the second was for
> > memory, and the third was for memory but with the endian swapped.  We
> > typically only used one of these BARs.
> >
> > Complicating that BARs usage was the fact that the PCIe HW would do a
> > baroque internal mapping of system memory, and concatenate the regions of
> > multiple memory controllers.
> >
> > Newer chips such as the 7712 and Cable Modem SOCs have taken a step forward
> > and now provide multiple inbound BARs.  This works in concert with the
> > dma-ranges property, where each provided range becomes an inbound BAR.
> >
> > This commit provides support for these new chips and their multiple
> > inbound BARs but also keeps the legacy support for the older system.
> >
>
> BAR belongs to the endpoints not to the RC. How can the RC have 'BARs'? RC can
> only map endpoint BARs to MEM region. What you are referring to is 'MEM region'
> maybe?

Agreed, it is confusing.  Long story short, the HW team gave the
inbound windows the label "BAR".   We will still have to use their
register names,
e.g. PCIE_MISC_RC_BAR4_CONFIG_LO, but what I can do is change
for example "struct rc_bar" to "struct inbound_win" as well as make similar
changes to the code and function names.

Let's assume you will be okay with my plan above; if not, please tell
me what you would prefer.

Regards,
Jim Quinlan
Broadcom STB/CM
>
> - Mani
>
> > Signed-off-by: Jim Quinlan <james.quinlan@...adcom.com>
> > Reviewed-by: Stanimir Varbanov <svarbanov@...e.de>
> > ---
> >  drivers/pci/controller/pcie-brcmstb.c | 216 ++++++++++++++++++++------
> >  1 file changed, 167 insertions(+), 49 deletions(-)
> >
> > diff --git a/drivers/pci/controller/pcie-brcmstb.c b/drivers/pci/controller/pcie-brcmstb.c
> > index 8ab5a8ca05b4..c44a92217855 100644
> > --- a/drivers/pci/controller/pcie-brcmstb.c
> > +++ b/drivers/pci/controller/pcie-brcmstb.c
> > @@ -75,15 +75,12 @@
> >  #define PCIE_MEM_WIN0_HI(win)        \
> >               PCIE_MISC_CPU_2_PCIE_MEM_WIN0_HI + ((win) * 8)
> >
> > +#define PCIE_BRCM_MAX_RC_BARS                                16
> >  #define PCIE_MISC_RC_BAR1_CONFIG_LO                  0x402c
> >  #define  PCIE_MISC_RC_BAR1_CONFIG_LO_SIZE_MASK               0x1f
> >
> > -#define PCIE_MISC_RC_BAR2_CONFIG_LO                  0x4034
> > -#define  PCIE_MISC_RC_BAR2_CONFIG_LO_SIZE_MASK               0x1f
> > -#define PCIE_MISC_RC_BAR2_CONFIG_HI                  0x4038
> > +#define PCIE_MISC_RC_BAR4_CONFIG_LO                  0x40d4
> >
> > -#define PCIE_MISC_RC_BAR3_CONFIG_LO                  0x403c
> > -#define  PCIE_MISC_RC_BAR3_CONFIG_LO_SIZE_MASK               0x1f
> >
> >  #define PCIE_MISC_MSI_BAR_CONFIG_LO                  0x4044
> >  #define PCIE_MISC_MSI_BAR_CONFIG_HI                  0x4048
> > @@ -130,6 +127,10 @@
> >         (PCIE_MISC_HARD_PCIE_HARD_DEBUG_CLKREQ_DEBUG_ENABLE_MASK | \
> >          PCIE_MISC_HARD_PCIE_HARD_DEBUG_L1SS_ENABLE_MASK)
> >
> > +#define PCIE_MISC_UBUS_BAR1_CONFIG_REMAP                     0x40ac
> > +#define  PCIE_MISC_UBUS_BAR1_CONFIG_REMAP_ACCESS_EN_MASK     BIT(0)
> > +#define PCIE_MISC_UBUS_BAR4_CONFIG_REMAP                     0x410c
> > +
> >  #define PCIE_MSI_INTR2_BASE          0x4500
> >
> >  /* Offsets from INTR2_CPU and MSI_INTR2 BASE offsets */
> > @@ -217,12 +218,20 @@ enum pcie_type {
> >       BCM4908,
> >       BCM7278,
> >       BCM2711,
> > +     BCM7712,
> > +};
> > +
> > +struct rc_bar {
> > +     u64 size;
> > +     u64 pci_offset;
> > +     u64 cpu_addr;
> >  };
> >
> >  struct pcie_cfg_data {
> >       const int *offsets;
> >       const enum pcie_type type;
> >       const bool has_phy;
> > +     unsigned int num_inbound;
> >       void (*perst_set)(struct brcm_pcie *pcie, u32 val);
> >       void (*bridge_sw_init_set)(struct brcm_pcie *pcie, u32 val);
> >  };
> > @@ -274,6 +283,7 @@ struct brcm_pcie {
> >       struct subdev_regulators *sr;
> >       bool                    ep_wakeup_capable;
> >       bool                    has_phy;
> > +     int                     num_inbound;
> >  };
> >
> >  static inline bool is_bmips(const struct brcm_pcie *pcie)
> > @@ -789,23 +799,61 @@ static void brcm_pcie_perst_set_generic(struct brcm_pcie *pcie, u32 val)
> >       writel(tmp, pcie->base + PCIE_RGR1_SW_INIT_1(pcie));
> >  }
> >
> > -static int brcm_pcie_get_rc_bar2_size_and_offset(struct brcm_pcie *pcie,
> > -                                                     u64 *rc_bar2_size,
> > -                                                     u64 *rc_bar2_offset)
> > +static inline void set_bar(struct rc_bar *b, int *count, u64 size,
> > +                        u64 cpu_addr, u64 pci_offset)
> > +{
> > +     b->size = size;
> > +     b->cpu_addr = cpu_addr;
> > +     b->pci_offset = pci_offset;
> > +     (*count)++;
> > +}
> > +
> > +static int brcm_pcie_get_inbound_wins(struct brcm_pcie *pcie,
> > +                                   struct rc_bar rc_bars[])
> >  {
> >       struct pci_host_bridge *bridge = pci_host_bridge_from_priv(pcie);
> > +     u64 pci_offset, cpu_addr, size = 0, tot_size = 0;
> >       struct resource_entry *entry;
> >       struct device *dev = pcie->dev;
> >       u64 lowest_pcie_addr = ~(u64)0;
> > -     int ret, i = 0;
> > -     u64 size = 0;
> > +     int ret, i = 0, n = 0;
> > +
> > +     /*
> > +      * The HW registers (and PCIe) use order-1 numbering for BARs. As
> > +      * such, we have rc_bars[0] unused and BAR1 starts at rc_bars[1].
> > +      */
> > +     struct rc_bar *b_begin = &rc_bars[1];
> > +     struct rc_bar *b = b_begin;
> > +
> > +     /*
> > +      * STB chips beside 7712 disable the first inbound window default.
> > +      * Rather being mapped to system memory it is mapped to the
> > +      * internal registers of the SoC.  This feature is deprecated, has
> > +      * security considerations, and is not implemented in our modern
> > +      * SoCs.
> > +      */
> > +     if (pcie->type != BCM7712)
> > +             set_bar(b++, &n, 0, 0, 0);
> >
> >       resource_list_for_each_entry(entry, &bridge->dma_ranges) {
> >               u64 pcie_beg = entry->res->start - entry->offset;
> > +             u64 cpu_beg = entry->res->start;
> >
> > -             size += entry->res->end - entry->res->start + 1;
> > +             size = resource_size(entry->res);
> > +             tot_size += size;
> >               if (pcie_beg < lowest_pcie_addr)
> >                       lowest_pcie_addr = pcie_beg;
> > +             /*
> > +              * 7712 and newer chips may have many BARs, with each
> > +              * offering a non-overlapping viewport to system memory.
> > +              * That being said, each BARs size must still be a power of
> > +              * two.
> > +              */
> > +             if (pcie->type == BCM7712)
> > +                     set_bar(b++, &n, size, cpu_beg, pcie_beg);
> > +
> > +             if (n > pcie->num_inbound)
> > +                     break;
> >       }
> >
> >       if (lowest_pcie_addr == ~(u64)0) {
> > @@ -813,13 +861,20 @@ static int brcm_pcie_get_rc_bar2_size_and_offset(struct brcm_pcie *pcie,
> >               return -EINVAL;
> >       }
> >
> > +     /*
> > +      * 7712 and newer chips do not have an internal memory mapping system
> > +      * that enables multiple memory controllers.  As such, it can return
> > +      * now w/o doing special configuration.
> > +      */
> > +     if (pcie->type == BCM7712)
> > +             return n;
> > +
> >       ret = of_property_read_variable_u64_array(pcie->np, "brcm,scb-sizes", pcie->memc_size, 1,
> >                                                 PCIE_BRCM_MAX_MEMC);
> > -
> >       if (ret <= 0) {
> >               /* Make an educated guess */
> >               pcie->num_memc = 1;
> > -             pcie->memc_size[0] = 1ULL << fls64(size - 1);
> > +             pcie->memc_size[0] = 1ULL << fls64(tot_size - 1);
> >       } else {
> >               pcie->num_memc = ret;
> >       }
> > @@ -828,10 +883,15 @@ static int brcm_pcie_get_rc_bar2_size_and_offset(struct brcm_pcie *pcie,
> >       for (i = 0, size = 0; i < pcie->num_memc; i++)
> >               size += pcie->memc_size[i];
> >
> > -     /* System memory starts at this address in PCIe-space */
> > -     *rc_bar2_offset = lowest_pcie_addr;
> > -     /* The sum of all memc views must also be a power of 2 */
> > -     *rc_bar2_size = 1ULL << fls64(size - 1);
> > +     /* Our HW mandates that the window size must be a power of 2 */
> > +     size = 1ULL << fls64(size - 1);
> > +
> > +     /*
> > +      * For STB chips, the BAR2 cpu_addr is hardwired to the start
> > +      * of system memory, so we set it to 0.
> > +      */
> > +     cpu_addr = 0;
> > +     pci_offset = lowest_pcie_addr;
> >
> >       /*
> >        * We validate the inbound memory view even though we should trust
> > @@ -866,25 +926,89 @@ static int brcm_pcie_get_rc_bar2_size_and_offset(struct brcm_pcie *pcie,
> >        *   outbound memory @ 3GB). So instead it will  start at the 1x
> >        *   multiple of its size
> >        */
> > -     if (!*rc_bar2_size || (*rc_bar2_offset & (*rc_bar2_size - 1)) ||
> > -         (*rc_bar2_offset < SZ_4G && *rc_bar2_offset > SZ_2G)) {
> > +     if (!size || (pci_offset & (size - 1)) ||
> > +         (pci_offset < SZ_4G && pci_offset > SZ_2G)) {
> >               dev_err(dev, "Invalid rc_bar2_offset/size: size 0x%llx, off 0x%llx\n",
> > -                     *rc_bar2_size, *rc_bar2_offset);
> > +                     size, pci_offset);
> >               return -EINVAL;
> >       }
> >
> > -     return 0;
> > +     /* Enable BAR2, the inbound window for STB chips */
> > +     set_bar(b++, &n, size, cpu_addr, pci_offset);
> > +
> > +     /*
> > +      * Disable BAR3.  On some chips presents the same window as BAR2
> > +      * but the data appears in a settable endianness.
> > +      */
> > +     set_bar(b++, &n, 0, 0, 0);
> > +
> > +     return n;
> > +}
> > +
> > +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 + 8 * (bar - 4);
> > +}
> > +
> > +static void set_inbound_win_registers(struct brcm_pcie *pcie, const struct rc_bar *rc_bars,
> > +                                   int num_rc_bars)
> > +{
> > +     void __iomem *base = pcie->base;
> > +     int i;
> > +
> > +     for (i = 1; i <= num_rc_bars; i++) {
> > +             u64 pci_offset = rc_bars[i].pci_offset;
> > +             u64 cpu_addr = rc_bars[i].cpu_addr;
> > +             u64 size = rc_bars[i].size;
> > +             u32 reg_offset = brcm_bar_reg_offset(i);
> > +             u32 tmp = lower_32_bits(pci_offset);
> > +
> > +             u32p_replace_bits(&tmp, brcm_pcie_encode_ibar_size(size),
> > +                               PCIE_MISC_RC_BAR1_CONFIG_LO_SIZE_MASK);
> > +
> > +             /* Write low */
> > +             writel(tmp, base + reg_offset);
> > +             /* Write high */
> > +             writel(upper_32_bits(pci_offset), base + reg_offset + 4);
> > +
> > +             /*
> > +              * Most STB chips:
> > +              *     Do nothing.
> > +              * 7712:
> > +              *     All of their BARs need to be set.
> > +              */
> > +             if (pcie->type == BCM7712) {
> > +                     /* BUS remap register settings */
> > +                     reg_offset = brcm_ubus_reg_offset(i);
> > +                     tmp = lower_32_bits(cpu_addr) & ~0xfff;
> > +                     tmp |= PCIE_MISC_UBUS_BAR1_CONFIG_REMAP_ACCESS_EN_MASK;
> > +                     writel(tmp, base + reg_offset);
> > +                     tmp = upper_32_bits(cpu_addr);
> > +                     writel(tmp, base + reg_offset + 4);
> > +             }
> > +     }
> >  }
> >
> >  static int brcm_pcie_setup(struct brcm_pcie *pcie)
> >  {
> > -     u64 rc_bar2_offset, rc_bar2_size;
> > +     struct rc_bar rc_bars[PCIE_BRCM_MAX_RC_BARS];
> >       void __iomem *base = pcie->base;
> >       struct pci_host_bridge *bridge;
> >       struct resource_entry *entry;
> >       u32 tmp, burst, aspm_support;
> > -     int num_out_wins = 0;
> > -     int ret, memc;
> > +     int num_out_wins = 0, num_rc_bars = 0;
> > +     int memc;
> >
> >       /* Reset the bridge */
> >       pcie->bridge_sw_init_set(pcie, 1);
> > @@ -933,17 +1057,16 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
> >       u32p_replace_bits(&tmp, 1, PCIE_MISC_MISC_CTRL_PCIE_RCB_64B_MODE_MASK);
> >       writel(tmp, base + PCIE_MISC_MISC_CTRL);
> >
> > -     ret = brcm_pcie_get_rc_bar2_size_and_offset(pcie, &rc_bar2_size,
> > -                                                 &rc_bar2_offset);
> > -     if (ret)
> > -             return ret;
> > +     num_rc_bars = brcm_pcie_get_inbound_wins(pcie, rc_bars);
> > +     if (num_rc_bars < 0)
> > +             return num_rc_bars;
> >
> > -     tmp = lower_32_bits(rc_bar2_offset);
> > -     u32p_replace_bits(&tmp, brcm_pcie_encode_ibar_size(rc_bar2_size),
> > -                       PCIE_MISC_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);
> > +     set_inbound_win_registers(pcie, rc_bars, num_rc_bars);
> > +
> > +     if (!brcm_pcie_rc_mode(pcie)) {
> > +             dev_err(pcie->dev, "PCIe RC controller misconfigured as Endpoint\n");
> > +             return -EINVAL;
> > +     }
> >
> >       tmp = readl(base + PCIE_MISC_MISC_CTRL);
> >       for (memc = 0; memc < pcie->num_memc; memc++) {
> > @@ -965,25 +1088,12 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
> >        * 4GB or when the inbound area is smaller than 4GB (taking into
> >        * account the rounding-up we're forced to perform).
> >        */
> > -     if (rc_bar2_offset >= SZ_4G || (rc_bar2_size + rc_bar2_offset) < SZ_4G)
> > +     if (rc_bars[2].pci_offset >= SZ_4G ||
> > +         (rc_bars[2].size + rc_bars[2].pci_offset) < SZ_4G)
> >               pcie->msi_target_addr = BRCM_MSI_TARGET_ADDR_LT_4GB;
> >       else
> >               pcie->msi_target_addr = BRCM_MSI_TARGET_ADDR_GT_4GB;
> >
> > -     if (!brcm_pcie_rc_mode(pcie)) {
> > -             dev_err(pcie->dev, "PCIe RC controller misconfigured as Endpoint\n");
> > -             return -EINVAL;
> > -     }
> > -
> > -     /* disable the PCIe->GISB memory window (RC_BAR1) */
> > -     tmp = readl(base + PCIE_MISC_RC_BAR1_CONFIG_LO);
> > -     tmp &= ~PCIE_MISC_RC_BAR1_CONFIG_LO_SIZE_MASK;
> > -     writel(tmp, base + PCIE_MISC_RC_BAR1_CONFIG_LO);
> > -
> > -     /* disable the PCIe->SCB memory window (RC_BAR3) */
> > -     tmp = readl(base + PCIE_MISC_RC_BAR3_CONFIG_LO);
> > -     tmp &= ~PCIE_MISC_RC_BAR3_CONFIG_LO_SIZE_MASK;
> > -     writel(tmp, base + PCIE_MISC_RC_BAR3_CONFIG_LO);
> >
> >       /* Don't advertise L0s capability if 'aspm-no-l0s' */
> >       aspm_support = PCIE_LINK_STATE_L1;
> > @@ -1516,6 +1626,7 @@ static const struct pcie_cfg_data generic_cfg = {
> >       .type           = GENERIC,
> >       .perst_set      = brcm_pcie_perst_set_generic,
> >       .bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_generic,
> > +     .num_inbound    = 3,
> >  };
> >
> >  static const struct pcie_cfg_data bcm7425_cfg = {
> > @@ -1523,6 +1634,7 @@ static const struct pcie_cfg_data bcm7425_cfg = {
> >       .type           = BCM7425,
> >       .perst_set      = brcm_pcie_perst_set_generic,
> >       .bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_generic,
> > +     .num_inbound    = 3,
> >  };
> >
> >  static const struct pcie_cfg_data bcm7435_cfg = {
> > @@ -1530,6 +1642,7 @@ static const struct pcie_cfg_data bcm7435_cfg = {
> >       .type           = BCM7435,
> >       .perst_set      = brcm_pcie_perst_set_generic,
> >       .bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_generic,
> > +     .num_inbound    = 3,
> >  };
> >
> >  static const struct pcie_cfg_data bcm4908_cfg = {
> > @@ -1537,6 +1650,7 @@ static const struct pcie_cfg_data bcm4908_cfg = {
> >       .type           = BCM4908,
> >       .perst_set      = brcm_pcie_perst_set_4908,
> >       .bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_generic,
> > +     .num_inbound    = 3,
> >  };
> >
> >  static const int pcie_offset_bcm7278[] = {
> > @@ -1552,6 +1666,7 @@ static const struct pcie_cfg_data bcm7278_cfg = {
> >       .type           = BCM7278,
> >       .perst_set      = brcm_pcie_perst_set_7278,
> >       .bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_7278,
> > +     .num_inbound    = 3,
> >  };
> >
> >  static const struct pcie_cfg_data bcm2711_cfg = {
> > @@ -1559,6 +1674,7 @@ static const struct pcie_cfg_data bcm2711_cfg = {
> >       .type           = BCM2711,
> >       .perst_set      = brcm_pcie_perst_set_generic,
> >       .bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_generic,
> > +     .num_inbound    = 3,
> >  };
> >
> >  static const struct pcie_cfg_data bcm7216_cfg = {
> > @@ -1567,6 +1683,7 @@ static const struct pcie_cfg_data bcm7216_cfg = {
> >       .perst_set      = brcm_pcie_perst_set_7278,
> >       .bridge_sw_init_set = brcm_pcie_bridge_sw_init_set_7278,
> >       .has_phy        = true,
> > +     .num_inbound    = 3,
> >  };
> >
> >  static const struct of_device_id brcm_pcie_match[] = {
> > @@ -1623,6 +1740,7 @@ static int brcm_pcie_probe(struct platform_device *pdev)
> >       pcie->perst_set = data->perst_set;
> >       pcie->bridge_sw_init_set = data->bridge_sw_init_set;
> >       pcie->has_phy = data->has_phy;
> > +     pcie->num_inbound = data->num_inbound;
> >
> >       pcie->base = devm_platform_ioremap_resource(pdev, 0);
> >       if (IS_ERR(pcie->base))
> > --
> > 2.17.1
> >
>
>
>
> --
> மணிவண்ணன் சதாசிவம்

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