Messages in this thread | | | Subject | Re: [PATCH 4/4] PCI: brcmstb: add MSI capability | Date | Thu, 07 Nov 2019 16:49:36 +0109 | From | Marc Zyngier <> |
| |
On 2019-11-06 22:54, Nicolas Saenz Julienne wrote: > From: Jim Quinlan <james.quinlan@broadcom.com> > > This commit adds MSI to the Broadcom STB PCIe host controller. It > does > not add MSIX since that functionality is not in the HW. The MSI > controller is physically located within the PCIe block, however, > there > is no reason why the MSI controller could not be moved elsewhere in > the future. > > Since the internal Brcmstb MSI controller is intertwined with the > PCIe > controller, it is not its own platform device but rather part of the > PCIe platform device. > > This is based on Jim's original submission[1] with some slight > changes > regarding how pcie->msi_target_addr is decided. > > [1] https://patchwork.kernel.org/patch/10605955/ > > Signed-off-by: Jim Quinlan <james.quinlan@broadcom.com> > Co-developed-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de> > --- > drivers/pci/controller/Kconfig | 2 +- > drivers/pci/controller/pcie-brcmstb.c | 333 > +++++++++++++++++++++++++- > 2 files changed, 332 insertions(+), 3 deletions(-) > > diff --git a/drivers/pci/controller/Kconfig > b/drivers/pci/controller/Kconfig > index 8b3aae91d8af..99b972ad3f2f 100644 > --- a/drivers/pci/controller/Kconfig > +++ b/drivers/pci/controller/Kconfig > @@ -284,7 +284,7 @@ config VMD > config PCIE_BRCMSTB > bool "Broadcom Brcmstb PCIe host controller" > depends on ARCH_BRCMSTB || BMIPS_GENERIC > - depends on OF > + depends on OF && PCI_MSI > depends on SOC_BRCMSTB > default ARCH_BRCMSTB || BMIPS_GENERIC > help > diff --git a/drivers/pci/controller/pcie-brcmstb.c > b/drivers/pci/controller/pcie-brcmstb.c > index 880ec11d06a1..26053e69b95f 100644 > --- a/drivers/pci/controller/pcie-brcmstb.c > +++ b/drivers/pci/controller/pcie-brcmstb.c > @@ -1,6 +1,7 @@ > // SPDX-License-Identifier: GPL-2.0 > /* Copyright (C) 2009 - 2019 Broadcom */ > > +#include <linux/bitops.h> > #include <linux/clk.h> > #include <linux/compiler.h> > #include <linux/delay.h> > @@ -8,11 +9,13 @@ > #include <linux/interrupt.h> > #include <linux/io.h> > #include <linux/ioport.h> > +#include <linux/irqchip/chained_irq.h> > #include <linux/irqdomain.h> > #include <linux/kernel.h> > #include <linux/list.h> > #include <linux/log2.h> > #include <linux/module.h> > +#include <linux/msi.h> > #include <linux/of_address.h> > #include <linux/of_irq.h> > #include <linux/of_pci.h> > @@ -46,6 +49,9 @@ > #define PCIE_MISC_RC_BAR2_CONFIG_LO 0x4034 > #define PCIE_MISC_RC_BAR2_CONFIG_HI 0x4038 > #define PCIE_MISC_RC_BAR3_CONFIG_LO 0x403c > +#define PCIE_MISC_MSI_BAR_CONFIG_LO 0x4044 > +#define PCIE_MISC_MSI_BAR_CONFIG_HI 0x4048 > +#define PCIE_MISC_MSI_DATA_CONFIG 0x404c > #define PCIE_MISC_PCIE_CTRL 0x4064 > #define PCIE_MISC_PCIE_STATUS 0x4068 > #define PCIE_MISC_REVISION 0x406c > @@ -54,6 +60,7 @@ > #define PCIE_MISC_CPU_2_PCIE_MEM_WIN0_LIMIT_HI 0x4084 > #define PCIE_MISC_HARD_PCIE_HARD_DEBUG 0x4204 > #define PCIE_INTR2_CPU_BASE 0x4300 > +#define PCIE_MSI_INTR2_BASE 0x4500 > > /* > * Broadcom Settop Box PCIe Register Field shift and mask info. The > @@ -114,6 +121,8 @@ > > #define BRCM_NUM_PCIE_OUT_WINS 0x4 > #define BRCM_MAX_SCB 0x4 > +#define BRCM_INT_PCI_MSI_NR 32 > +#define BRCM_PCIE_HW_REV_33 0x0303 > > #define BRCM_MSI_TARGET_ADDR_LT_4GB 0x0fffffffcULL > #define BRCM_MSI_TARGET_ADDR_GT_4GB 0xffffffffcULL > @@ -199,6 +208,33 @@ struct brcm_window { > dma_addr_t size; > }; > > +struct brcm_msi { > + struct device *dev; > + void __iomem *base; > + struct device_node *dn; > + struct irq_domain *msi_domain; > + struct irq_domain *inner_domain; > + struct mutex lock; /* guards the alloc/free operations */ > + u64 target_addr; > + int irq; > + > + /* intr_base is the base pointer for interrupt status/set/clr regs > */ > + void __iomem *intr_base; > + > + /* intr_legacy_mask indicates how many bits are MSI interrupts */ > + u32 intr_legacy_mask; > + > + /* > + * intr_legacy_offset indicates bit position of MSI_01. It is > + * to map the register bit position to a hwirq that starts at 0. > + */ > + u32 intr_legacy_offset; > + > + /* used indicates which MSI interrupts have been alloc'd */ > + unsigned long used; > + unsigned int rev; > +}; > + > /* Internal PCIe Host Controller Information.*/ > struct brcm_pcie { > struct device *dev; > @@ -211,7 +247,10 @@ struct brcm_pcie { > bool suspended; > bool ssc; > int gen; > + u64 msi_target_addr; > struct brcm_window out_wins[BRCM_NUM_PCIE_OUT_WINS]; > + struct brcm_msi *msi; > + bool msi_internal;
Do you need both of these fields? Is there any case where msi is valid and msi_internal is false?
> unsigned int rev; > const int *reg_offsets; > const int *reg_field_info; > @@ -477,6 +516,267 @@ static void brcm_pcie_set_outbound_win(struct > brcm_pcie *pcie, > LIMIT, tmp); > } > > +static struct irq_chip brcm_msi_irq_chip = { > + .name = "Brcm_MSI", > + .irq_mask = pci_msi_mask_irq, > + .irq_unmask = pci_msi_unmask_irq, > +}; > + > +static struct msi_domain_info brcm_msi_domain_info = { > + .flags = (MSI_FLAG_USE_DEF_DOM_OPS | MSI_FLAG_USE_DEF_CHIP_OPS | > + MSI_FLAG_PCI_MSIX),
Is there a particular reason for not supporting MultiMSI? I won't miss it, but it might be worth documenting the restriction if the HW cannot support it (though I can't immediately see why).
> + .chip = &brcm_msi_irq_chip, > +}; > + > +static void brcm_pcie_msi_isr(struct irq_desc *desc) > +{ > + struct irq_chip *chip = irq_desc_get_chip(desc); > + struct brcm_msi *msi; > + unsigned long status, virq; > + u32 mask, bit, hwirq; > + struct device *dev; > + > + chained_irq_enter(chip, desc); > + msi = irq_desc_get_handler_data(desc); > + mask = msi->intr_legacy_mask; > + dev = msi->dev; > + > + while ((status = bcm_readl(msi->intr_base + STATUS) & mask)) {
Is this loop really worth it? If, as I imagine, this register is at the end of a wet piece of string, this additional read (likely to return zero) will have a measurable latency impact...
> + for_each_set_bit(bit, &status, BRCM_INT_PCI_MSI_NR) { > + /* clear the interrupt */ > + bcm_writel(1 << bit, msi->intr_base + CLR); > + > + /* Account for legacy interrupt offset */ > + hwirq = bit - msi->intr_legacy_offset; > + > + virq = irq_find_mapping(msi->inner_domain, hwirq); > + if (virq) { > + if (msi->used & (1 << hwirq)) > + generic_handle_irq(virq); > + else > + dev_info(dev, "unhandled MSI %d\n", > + hwirq);
Can this ever happen? If you've found the mapping in the irqdomain, the MSI obviously has been allocated. Or am I missing something?
> + } else { > + /* Unknown MSI, just clear it */ > + dev_dbg(dev, "unexpected MSI\n"); > + } > + } > + } > + chained_irq_exit(chip, desc); > +} > + > +static void brcm_compose_msi_msg(struct irq_data *data, struct > msi_msg *msg) > +{ > + struct brcm_msi *msi = irq_data_get_irq_chip_data(data); > + u32 temp; > + > + msg->address_lo = lower_32_bits(msi->target_addr); > + msg->address_hi = upper_32_bits(msi->target_addr); > + temp = bcm_readl(msi->base + PCIE_MISC_MSI_DATA_CONFIG);
Do you have to reload it from the HW?
> + msg->data = ((temp >> 16) & (temp & 0xffff)) | data->hwirq; > +} > + > +static int brcm_msi_set_affinity(struct irq_data *irq_data, > + const struct cpumask *mask, bool force) > +{ > + return -EINVAL; > +} > + > +static struct irq_chip brcm_msi_bottom_irq_chip = { > + .name = "Brcm_MSI", > + .irq_compose_msi_msg = brcm_compose_msi_msg, > + .irq_set_affinity = brcm_msi_set_affinity, > +}; > + > +static int brcm_msi_alloc(struct brcm_msi *msi) > +{ > + int bit, hwirq; > + > + mutex_lock(&msi->lock); > + bit = ~msi->used ? ffz(msi->used) : -1; > + > + if (bit >= 0 && bit < BRCM_INT_PCI_MSI_NR) { > + msi->used |= (1 << bit); > + hwirq = bit - msi->intr_legacy_offset; > + } else { > + hwirq = -ENOSPC; > + }
Please consider using bitmap_find_free_region() and co, instead of open coding your allocator.
> + > + mutex_unlock(&msi->lock); > + return hwirq; > +} > + > +static void brcm_msi_free(struct brcm_msi *msi, unsigned long hwirq) > +{ > + mutex_lock(&msi->lock); > + msi->used &= ~(1 << (hwirq + msi->intr_legacy_offset)); > + mutex_unlock(&msi->lock); > +} > + > +static int brcm_irq_domain_alloc(struct irq_domain *domain, unsigned > int virq, > + unsigned int nr_irqs, void *args) > +{ > + struct brcm_msi *msi = domain->host_data; > + int hwirq; > + > + hwirq = brcm_msi_alloc(msi); > + > + if (hwirq < 0) > + return hwirq; > + > + irq_domain_set_info(domain, virq, (irq_hw_number_t)hwirq, > + &brcm_msi_bottom_irq_chip, domain->host_data, > + handle_simple_irq, NULL, NULL);
simple_irq doesn't quite match what this does. This really should use an edge flow.
> + return 0; > +} > + > +static void brcm_irq_domain_free(struct irq_domain *domain, > + unsigned int virq, unsigned int nr_irqs) > +{ > + struct irq_data *d = irq_domain_get_irq_data(domain, virq); > + struct brcm_msi *msi = irq_data_get_irq_chip_data(d); > + > + brcm_msi_free(msi, d->hwirq); > +} > + > +static void brcm_msi_set_regs(struct brcm_msi *msi) > +{ > + u32 data_val, msi_lo, msi_hi; > + > + if (msi->rev >= BRCM_PCIE_HW_REV_33) { > + /* > + * ffe0 -- least sig 5 bits are 0 indicating 32 msgs > + * 6540 -- this is our arbitrary unique data value > + */ > + data_val = 0xffe06540; > + } else { > + /* > + * fff8 -- least sig 3 bits are 0 indicating 8 msgs > + * 6540 -- this is our arbitrary unique data value > + */ > + data_val = 0xfff86540; > + } > + > + /* > + * Make sure we are not masking MSIs. Note that MSIs can be > masked, > + * but that occurs on the PCIe EP device
That's not a guarantee, specially with plain MultiMSI. I'm actually minded to move the masking to be purely local on the MSI controllers I maintain.
> + */ > + bcm_writel(0xffffffff & msi->intr_legacy_mask, > + msi->intr_base + MASK_CLR); > + > + msi_lo = lower_32_bits(msi->target_addr); > + msi_hi = upper_32_bits(msi->target_addr); > + /* > + * The 0 bit of PCIE_MISC_MSI_BAR_CONFIG_LO is repurposed to MSI > + * enable, which we set to 1. > + */ > + bcm_writel(msi_lo | 1, msi->base + PCIE_MISC_MSI_BAR_CONFIG_LO); > + bcm_writel(msi_hi, msi->base + PCIE_MISC_MSI_BAR_CONFIG_HI); > + bcm_writel(data_val, msi->base + PCIE_MISC_MSI_DATA_CONFIG); > +} > + > +static const struct irq_domain_ops msi_domain_ops = { > + .alloc = brcm_irq_domain_alloc, > + .free = brcm_irq_domain_free, > +}; > + > +static int brcm_allocate_domains(struct brcm_msi *msi) > +{ > + struct fwnode_handle *fwnode = of_node_to_fwnode(msi->dn); > + struct device *dev = msi->dev; > + > + msi->inner_domain = irq_domain_add_linear(NULL, > BRCM_INT_PCI_MSI_NR, > + &msi_domain_ops, msi); > + if (!msi->inner_domain) { > + dev_err(dev, "failed to create IRQ domain\n"); > + return -ENOMEM; > + } > + > + msi->msi_domain = pci_msi_create_irq_domain(fwnode, > + &brcm_msi_domain_info, > + msi->inner_domain); > + if (!msi->msi_domain) { > + dev_err(dev, "failed to create MSI domain\n"); > + irq_domain_remove(msi->inner_domain); > + return -ENOMEM; > + } > + > + return 0; > +} > + > +static void brcm_free_domains(struct brcm_msi *msi) > +{ > + irq_domain_remove(msi->msi_domain); > + irq_domain_remove(msi->inner_domain); > +} > + > +static void brcm_msi_remove(struct brcm_pcie *pcie) > +{ > + struct brcm_msi *msi = pcie->msi; > + > + if (!msi) > + return; > + irq_set_chained_handler(msi->irq, NULL); > + irq_set_handler_data(msi->irq, NULL); > + brcm_free_domains(msi); > +} > + > +static int brcm_pcie_enable_msi(struct brcm_pcie *pcie) > +{ > + struct brcm_msi *msi; > + int irq, ret; > + struct device *dev = pcie->dev; > + > + irq = irq_of_parse_and_map(dev->of_node, 1); > + if (irq <= 0) { > + dev_err(dev, "cannot map msi intr\n"); > + return -ENODEV; > + } > + > + msi = devm_kzalloc(dev, sizeof(struct brcm_msi), GFP_KERNEL); > + if (!msi) > + return -ENOMEM; > + > + msi->dev = dev; > + msi->base = pcie->base; > + msi->rev = pcie->rev; > + msi->dn = pcie->dn; > + msi->target_addr = pcie->msi_target_addr; > + msi->irq = irq; > + > + ret = brcm_allocate_domains(msi); > + if (ret) > + return ret;
You seem to rely on the devm_* allocators to cleanup on failure. But as far as I can see, failing to initialize the MSI subsystem doesn't translate in a PCIe init failure, hence keeping the memory around.
> + > + irq_set_chained_handler_and_data(msi->irq, brcm_pcie_msi_isr, msi); > + > + if (msi->rev >= BRCM_PCIE_HW_REV_33) { > + msi->intr_base = msi->base + PCIE_MSI_INTR2_BASE; > + /* > + * This version of PCIe hw has only 32 intr bits > + * starting at bit position 0. > + */ > + msi->intr_legacy_mask = 0xffffffff; > + msi->intr_legacy_offset = 0x0; > + msi->used = 0x0; > + > + } else { > + msi->intr_base = msi->base + PCIE_INTR2_CPU_BASE; > + /* > + * This version of PCIe hw has only 8 intr bits starting > + * at bit position 24. > + */ > + msi->intr_legacy_mask = 0xff000000; > + msi->intr_legacy_offset = 24; > + msi->used = 0x00ffffff; > + } > + > + brcm_msi_set_regs(msi); > + pcie->msi = msi; > + > + return 0; > +} > + > /* Configuration space read/write support */ > static int cfg_index(int busnr, int devfn, int reg) > { > @@ -643,6 +943,18 @@ static int brcm_pcie_setup(struct brcm_pcie > *pcie) > if (ret) > return ret; > > + /* > + * We ideally want the MSI target address to be located in the > 32bit > + * addressable memory area. Some devices might depend on it. This > is > + * possible either when the inbound window is located above the > lower > + * 4GB or when the inbound and outbound areas fit in the lower 4GB > of > + * memory. > + */ > + if (rc_bar2_offset >= SZ_4G || (rc_bar2_size + rc_bar2_offset) <= > SZ_4G) > + pcie->msi_target_addr = BRCM_MSI_TARGET_ADDR_LT_4GB; > + else > + pcie->msi_target_addr = BRCM_MSI_TARGET_ADDR_GT_4GB; > + > tmp = lower_32_bits(rc_bar2_offset); > tmp = INSERT_FIELD(tmp, PCIE_MISC_RC_BAR2_CONFIG_LO, SIZE, > encode_ibar_size(rc_bar2_size)); > @@ -816,6 +1128,9 @@ static int brcm_pcie_resume(struct device *dev) > if (ret) > return ret; > > + if (pcie->msi && pcie->msi_internal) > + brcm_msi_set_regs(pcie->msi); > + > pcie->suspended = false; > > return 0; > @@ -823,6 +1138,7 @@ static int brcm_pcie_resume(struct device *dev) > > static void _brcm_pcie_remove(struct brcm_pcie *pcie) > { > + brcm_msi_remove(pcie); > turn_off(pcie); > clk_disable_unprepare(pcie->clk); > clk_put(pcie->clk); > @@ -847,7 +1163,7 @@ MODULE_DEVICE_TABLE(of, brcm_pcie_match); > > static int brcm_pcie_probe(struct platform_device *pdev) > { > - struct device_node *dn = pdev->dev.of_node; > + struct device_node *dn = pdev->dev.of_node, *msi_dn; > const struct of_device_id *of_id; > const struct pcie_cfg_data *data; > struct resource *res; > @@ -923,6 +1239,20 @@ static int brcm_pcie_probe(struct > platform_device *pdev) > if (ret) > goto fail; > > + msi_dn = of_parse_phandle(pcie->dn, "msi-parent", 0); > + /* Use the internal MSI if no msi-parent property */ > + if (!msi_dn) > + msi_dn = pcie->dn; > + > + if (pci_msi_enabled() && msi_dn == pcie->dn) { > + ret = brcm_pcie_enable_msi(pcie); > + if (ret) > + dev_err(pcie->dev, > + "probe of internal MSI failed: %d)", ret); > + else > + pcie->msi_internal = true; > + } > + > bridge->dev.parent = &pdev->dev; > bridge->busnr = 0; > bridge->ops = &brcm_pcie_ops; > @@ -944,7 +1274,6 @@ static int brcm_pcie_probe(struct > platform_device *pdev) > pcie->root_bus = bridge->bus; > > return 0; > - > fail: > _brcm_pcie_remove(pcie); > return ret;
Thanks,
M. -- Jazz is not dead. It just smells funny...
| |