Re: [PATCH v3 6/8] PCI: brcmstb: Add MSI capability
From: Bjorn Helgaas
Date: Tue Dec 12 2017 - 17:43:44 EST
On Tue, Nov 14, 2017 at 05:12:10PM -0500, Jim Quinlan wrote:
> 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.
>
> Signed-off-by: Jim Quinlan <jim2101024@xxxxxxxxx>
> ---
> drivers/pci/host/pcie-brcmstb.c | 372 ++++++++++++++++++++++++++++++++++++++--
> 1 file changed, 359 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/pci/host/pcie-brcmstb.c b/drivers/pci/host/pcie-brcmstb.c
> index 5f4c6aa..89bad31 100644
> --- a/drivers/pci/host/pcie-brcmstb.c
> +++ b/drivers/pci/host/pcie-brcmstb.c
> @@ -11,6 +11,7 @@
> * GNU General Public License for more details.
> */
>
> +#include <linux/bitops.h>
> #include <linux/clk.h>
> #include <linux/compiler.h>
> #include <linux/delay.h>
> @@ -18,15 +19,16 @@
> #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>
> -#include <linux/of_pci.h>
> #include <linux/of_platform.h>
> #include <linux/pci.h>
> #include <linux/printk.h>
> @@ -56,6 +58,9 @@
> #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
> @@ -64,6 +69,7 @@
> #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
> @@ -124,6 +130,8 @@
>
> #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
> @@ -212,6 +220,30 @@ struct brcm_window {
> dma_addr_t size;
> };
>
> +struct brcm_msi {
> + 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;
> +
> + void __iomem *base;
> + struct device *dev;
> + struct device_node *dn;
> + unsigned int rev;
I think you aligned the structure elements for brcm_pcie, so do the
same here.
> +};
> +
> /* Internal PCIe Host Controller Information.*/
> struct brcm_pcie {
> struct list_head list;
> @@ -227,7 +259,10 @@ struct brcm_pcie {
> int num_out_wins;
> 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;
> unsigned int rev;
> const int *reg_offsets;
> const int *reg_field_info;
> @@ -240,6 +275,13 @@ struct pcie_cfg_data {
> const enum pcie_type type;
> };
>
> +struct brcm_info {
> + int rev;
> + u64 msi_target_addr;
> + void __iomem *base;
> + struct brcm_msi *msi;
And here.
> +};
> +
> static const int pcie_reg_field_info[] = {
> [RGR1_SW_INIT_1_INIT_MASK] = 0x2,
> [RGR1_SW_INIT_1_INIT_SHIFT] = 0x1,
> @@ -546,6 +588,264 @@ static void brcm_pcie_set_outbound_win(struct brcm_pcie *pcie,
> }
> }
>
> +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),
> + .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)) {
> + 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);
> + } 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);
> + 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;
> + }
> +
> + 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);
> + 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);
> +}
> +
> +void brcm_msi_set_regs(struct brcm_msi *msi)
Static?
> +{
> + 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
> + */
> + 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);
> +}
> +
> +void brcm_msi_remove(struct brcm_msi *msi)
Static?
> +{
> + if (!msi)
> + return;
> + irq_set_chained_handler(msi->irq, NULL);
> + irq_set_handler_data(msi->irq, NULL);
> + brcm_free_domains(msi);
> +}
> +
> +int brcm_msi_probe(struct platform_device *pdev, struct brcm_info *info)
Static?
I don't think we're probing a separate device here, so this isn't
quite the right name. I see it looks like you're using a pattern from
altera or xgene. But those have some weird structure where they have
extra of_match_tables, and you don't.
> +{
> + struct brcm_msi *msi;
> + int irq, ret;
> +
> + irq = irq_of_parse_and_map(pdev->dev.of_node, 1);
> + if (irq <= 0) {
> + dev_err(&pdev->dev, "cannot map msi intr\n");
> + return -ENODEV;
> + }
> +
> + msi = devm_kzalloc(&pdev->dev, sizeof(struct brcm_msi), GFP_KERNEL);
> + if (!msi)
> + return -ENOMEM;
> +
> + msi->dev = &pdev->dev;
> + msi->base = info->base;
> + msi->rev = info->rev;
> + msi->dn = pdev->dev.of_node;
> + msi->target_addr = info->msi_target_addr;
> + msi->irq = irq;
> +
> + ret = brcm_allocate_domains(msi);
> + if (ret)
> + return ret;
> +
> + 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);
> + info->msi = msi;
> +
> + return 0;
> +}
> +
> /* Configuration space read/write support */
> static int cfg_index(int busnr, int devfn, int reg)
> {
> @@ -812,6 +1112,7 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
> int i, j, ret, limit;
> u16 nlw, cls, lnksta;
> bool ssc_good = false;
> + u64 msi_target_addr;
>
> /* reset the bridge and the endpoint device */
> /* field: PCIE_BRIDGE_SW_INIT = 1 */
> @@ -855,14 +1156,17 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
> * The PCIe host controller by design must set the inbound
> * viewport to be a contiguous arrangement of all of the
> * system's memory. In addition, its size mut be a power of
> - * two. To further complicate matters, the viewport must
> - * start on a pcie-address that is aligned on a multiple of its
> - * size. If a portion of the viewport does not represent
> - * system memory -- e.g. 3GB of memory requires a 4GB viewport
> - * -- we can map the outbound memory in or after 3GB and even
> - * though the viewport will overlap the outbound memory the
> - * controller will know to send outbound memory downstream and
> - * everything else upstream.
> + * two. Further, the MSI target address must NOT be placed
> + * inside this region, as the decoding logic will consider its
> + * address to be inbound memory traffic. To further
> + * complicate matters, the viewport must start on a
> + * pcie-address that is aligned on a multiple of its size.
> + * If a portion of the viewport does not represent system
> + * memory -- e.g. 3GB of memory requires a 4GB viewport --
> + * we can map the outbound memory in or after 3GB and even
> + * though the viewport will overlap the outbound memory
> + * the controller will know to send outbound memory downstream
> + * and everything else upstream.
> */
> rc_bar2_size = roundup_pow_of_two_64(total_mem_size);
>
> @@ -875,7 +1179,7 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
> if (dma_ranges) {
> /*
> * The best-case scenario is to place the inbound
> - * region in the first 4GB of pci-space, as some
> + * region in the first 4GB of pcie-space, as some
> * legacy devices can only address 32bits.
> * We would also like to put the MSI under 4GB
> * as well, since some devices require a 32bit
> @@ -884,6 +1188,14 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
> if (total_mem_size <= 0xc0000000ULL &&
> rc_bar2_size <= 0x100000000ULL) {
> rc_bar2_offset = 0;
> + /* If the viewport is less then 4GB we can fit
> + * the MSI target address under 4GB. Otherwise
> + * put it right below 64GB.
> + */
> + msi_target_addr =
> + (rc_bar2_size == 0x100000000ULL)
> + ? BRCM_MSI_TARGET_ADDR_GT_4GB
> + : BRCM_MSI_TARGET_ADDR_LT_4GB;
> } else {
> /*
> * The system memory is 4GB or larger so we
> @@ -893,8 +1205,12 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
> * start it at the 1x multiple of its size
> */
> rc_bar2_offset = rc_bar2_size;
> - }
>
> + /* Since we are starting the viewport at 4GB or
> + * higher, put the MSI target address below 4GB
> + */
> + msi_target_addr = BRCM_MSI_TARGET_ADDR_LT_4GB;
> + }
> } else {
> /*
> * Set simple configuration based on memory sizes
> @@ -902,7 +1218,12 @@ static int brcm_pcie_setup(struct brcm_pcie *pcie)
> * and set the MSI target address accordingly.
> */
> rc_bar2_offset = 0;
> +
> + msi_target_addr = (rc_bar2_size >= 0x100000000ULL)
> + ? BRCM_MSI_TARGET_ADDR_GT_4GB
> + : BRCM_MSI_TARGET_ADDR_LT_4GB;
> }
> + pcie->msi_target_addr = msi_target_addr;
>
> tmp = lower_32_bits(rc_bar2_offset);
> tmp = INSERT_FIELD(tmp, PCIE_MISC_RC_BAR2_CONFIG_LO, SIZE,
> @@ -1076,6 +1397,9 @@ 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;
> @@ -1083,6 +1407,7 @@ static int brcm_pcie_resume(struct device *dev)
>
> static void _brcm_pcie_remove(struct brcm_pcie *pcie)
> {
> + brcm_msi_remove(pcie->msi);
> turn_off(pcie);
> clk_disable_unprepare(pcie->clk);
> clk_put(pcie->clk);
> @@ -1111,7 +1436,7 @@ static int brcm_pcie_remove(struct platform_device *pdev)
>
> 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;
> int ret;
> @@ -1194,6 +1519,28 @@ 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) {
> + struct brcm_info info;
> +
> + info.rev = pcie->rev;
> + info.msi_target_addr = pcie->msi_target_addr;
> + info.base = pcie->base;
> +
> + ret = brcm_msi_probe(pdev, &info);
> + if (ret)
> + dev_err(pcie->dev,
> + "probe of internal MSI failed: %d)", ret);
> + else
> + pcie->msi_internal = true;
> +
> + pcie->msi = info.msi;
> + }
> +
> list_splice_init(&pcie->resources, &bridge->windows);
> bridge->dev.parent = &pdev->dev;
> bridge->busnr = 0;
> @@ -1216,7 +1563,6 @@ static int brcm_pcie_probe(struct platform_device *pdev)
> pcie->root_bus = bridge->bus;
>
> return 0;
> -
> fail:
> _brcm_pcie_remove(pcie);
> return ret;
> --
> 1.9.0.138.g2de3478
>