imsic_init() is introduced to parse device tree node, which has the following
bindings [2], and based on the parsed information update IMSIC configuration
which is stored in imsic_cfg.
The following helpers are introduces for imsic_init() usage:
- imsic_parse_node() parses IMSIC node from DTS
- imsic_get_parent_hartid() returns the hart ( CPU ) ID of the given device
tree node.
This patch is based on the code from [1].
Since Microchip originally developed imsic.{c,h}, an internal discussion with
them led to the decision to use the MIT license.
[1]
https://gitlab.com/xen-project/people/olkur/xen/-/commit/0b1a94f2bc3bb1a81cd26bb75f0bf578f84cb4d4
[2]
https://elixir.bootlin.com/linux/v6.12/source/Documentation/devicetree/bindings/interrupt-controller/riscv,imsics.yaml
Co-developed-by: Romain Caritey <romain.cari...@microchip.com>
Signed-off-by: Oleksii Kurochko <oleksii.kuroc...@gmail.com>
---
xen/arch/riscv/Makefile | 1 +
xen/arch/riscv/imsic.c | 286 +++++++++++++++++++++++++++++
xen/arch/riscv/include/asm/imsic.h | 66 +++++++
3 files changed, 353 insertions(+)
create mode 100644 xen/arch/riscv/imsic.c
create mode 100644 xen/arch/riscv/include/asm/imsic.h
diff --git a/xen/arch/riscv/Makefile b/xen/arch/riscv/Makefile
index 457e8e88a4..baa499a72d 100644
--- a/xen/arch/riscv/Makefile
+++ b/xen/arch/riscv/Makefile
@@ -2,6 +2,7 @@ obj-y += aplic.o
obj-y += cpufeature.o
obj-$(CONFIG_EARLY_PRINTK) += early_printk.o
obj-y += entry.o
+obj-y += imsic.o
obj-y += intc.o
obj-y += irq.o
obj-y += mm.o
diff --git a/xen/arch/riscv/imsic.c b/xen/arch/riscv/imsic.c
new file mode 100644
index 0000000000..99def9af2d
--- /dev/null
+++ b/xen/arch/riscv/imsic.c
@@ -0,0 +1,286 @@
+/* SPDX-License-Identifier: MIT */
+
+/*
+ * xen/arch/riscv/imsic.c
+ *
+ * RISC-V Incoming MSI Controller support
+ *
+ * (c) 2023 Microchip Technology Inc.
+ * (c) 2024 Vates
+ */
+
+#include <xen/const.h>
+#include <xen/device_tree.h>
+#include <xen/errno.h>
+#include <xen/init.h>
+#include <xen/macros.h>
+#include <xen/xmalloc.h>
+
+#include <asm/imsic.h>
+
+static struct imsic_config imsic_cfg;
+
+const struct imsic_config *imsic_get_config(void)
+{
+ return &imsic_cfg;
+}
+
+static int __init imsic_get_parent_hartid(struct dt_device_node *node,
+ unsigned int index,
+ unsigned long *hartid)
+{
+ int res;
+ unsigned long hart;
+ struct dt_phandle_args args;
+
+ /* Try the new-style interrupts-extended first */
+ res = dt_parse_phandle_with_args(node, "interrupts-extended",
+ "#interrupt-cells", index, &args);
+ if ( !res )
+ {
+ res = riscv_of_processor_hartid(args.np->parent, &hart);
+ if ( res < 0 )
+ return -EINVAL;
+
+ *hartid = hart;
+ }
+ return res;
+}
+
+
+static int imsic_parse_node(struct dt_device_node *node,
+ unsigned int *nr_parent_irqs)
+{
+ int rc;
+ unsigned int tmp;
+ paddr_t base_addr;
+
+ /* Find number of parent interrupts */
+ *nr_parent_irqs = dt_number_of_irq(node);
+ if ( !*nr_parent_irqs )
+ {
+ printk(XENLOG_ERR "%s: no parent irqs available\n", node->name);
+ return -ENOENT;
+ }
+
+ /* Find number of guest index bits in MSI address */
+ rc = dt_property_read_u32(node, "riscv,guest-index-bits",
+ &imsic_cfg.guest_index_bits);
+ if ( !rc )
+ imsic_cfg.guest_index_bits = 0;
+ tmp = BITS_PER_LONG - IMSIC_MMIO_PAGE_SHIFT;
+ if ( tmp < imsic_cfg.guest_index_bits )
+ {
+ printk(XENLOG_ERR "%s: guest index bits too big\n", node->name);
+ return -ENOENT;
+ }
+
+ /* Find number of HART index bits */
+ rc = dt_property_read_u32(node, "riscv,hart-index-bits",
+ &imsic_cfg.hart_index_bits);
+ if ( !rc )
+ {
+ /* Assume default value */
+ imsic_cfg.hart_index_bits = fls(*nr_parent_irqs);
+ if ( BIT(imsic_cfg.hart_index_bits, UL) < *nr_parent_irqs )
+ imsic_cfg.hart_index_bits++;
+ }
+ tmp = BITS_PER_LONG - IMSIC_MMIO_PAGE_SHIFT -
+ imsic_cfg.guest_index_bits;
+ if ( tmp < imsic_cfg.hart_index_bits )
+ {
+ printk(XENLOG_ERR "%s: HART index bits too big\n", node->name);
+ return -ENOENT;
+ }
+
+ /* Find number of group index bits */
+ rc = dt_property_read_u32(node, "riscv,group-index-bits",
+ &imsic_cfg.group_index_bits);
+ if ( !rc )
+ imsic_cfg.group_index_bits = 0;
+ tmp = BITS_PER_LONG - IMSIC_MMIO_PAGE_SHIFT -
+ imsic_cfg.guest_index_bits - imsic_cfg.hart_index_bits;
+ if ( tmp < imsic_cfg.group_index_bits )
+ {
+ printk(XENLOG_ERR "%s: group index bits too big\n", node->name);
+ return -ENOENT;
+ }
+
+ /* Find first bit position of group index */
+ tmp = IMSIC_MMIO_PAGE_SHIFT * 2;
+ rc = dt_property_read_u32(node, "riscv,group-index-shift",
+ &imsic_cfg.group_index_shift);
+ if ( !rc )
+ imsic_cfg.group_index_shift = tmp;
+ if ( imsic_cfg.group_index_shift < tmp )
+ {
+ printk(XENLOG_ERR "%s: group index shift too small\n", node->name);
+ return -ENOENT;
+ }
+ tmp = imsic_cfg.group_index_bits + imsic_cfg.group_index_shift - 1;
+ if ( tmp >= BITS_PER_LONG )
+ {
+ printk(XENLOG_ERR "%s: group index shift too big\n", node->name);
+ return -EINVAL;
+ }
+
+ /* Find number of interrupt identities */
+ rc = dt_property_read_u32(node, "riscv,num-ids", &imsic_cfg.nr_ids);
+ if ( !rc )
+ {
+ printk(XENLOG_ERR "%s: number of interrupt identities not found\n",
+ node->name);
+ return -ENOENT;
+ }
+
+ if ( (imsic_cfg.nr_ids < IMSIC_MIN_ID) ||
+ (imsic_cfg.nr_ids >= IMSIC_MAX_ID) ||
+ ((imsic_cfg.nr_ids & IMSIC_MIN_ID) != IMSIC_MIN_ID) )
+ {
+ printk(XENLOG_ERR "%s: invalid number of interrupt identities\n",
+ node->name);
+ return -EINVAL;
+ }
+
+ /* Compute base address */
+ imsic_cfg.nr_mmios = 0;
+ rc = dt_device_get_address(node, imsic_cfg.nr_mmios, &base_addr, NULL);
+ if (rc)
+ {
+ printk(XENLOG_ERR "%s: first MMIO resource not found\n", node->name);
+ return -EINVAL;
+ }
+
+ imsic_cfg.base_addr = base_addr;
+ imsic_cfg.base_addr &= ~(BIT(imsic_cfg.guest_index_bits +
+ imsic_cfg.hart_index_bits +
+ IMSIC_MMIO_PAGE_SHIFT, UL) - 1);
+ imsic_cfg.base_addr &= ~((BIT(imsic_cfg.group_index_bits, UL) - 1) <<
+ imsic_cfg.group_index_shift);
+
+ /* Find number of MMIO register sets */
+ imsic_cfg.nr_mmios++;
+ while ( !dt_device_get_address(node, imsic_cfg.nr_mmios, &base_addr, NULL)
)
+ imsic_cfg.nr_mmios++;
+
+ return 0;
+}
+
+int __init imsic_init(struct dt_device_node *node)
+{
+ int rc;
+ unsigned long reloff, hartid;
+ uint32_t nr_parent_irqs, index, nr_handlers = 0;
+ paddr_t base_addr;
+
+ /* Parse IMSIC node */
+ rc = imsic_parse_node(node, &nr_parent_irqs);
+ if ( rc )
+ return rc;
+
+ /* Allocate MMIO resource array */
+ imsic_cfg.mmios = xzalloc_array(struct imsic_mmios, imsic_cfg.nr_mmios);
+ if ( !imsic_cfg.mmios )
+ return -ENOMEM;
+
+ /* check MMIO register sets */
+ for ( int i = 0; i < imsic_cfg.nr_mmios; i++ )
+ {
+ rc = dt_device_get_address(node, i, &imsic_cfg.mmios[i].base_addr,
+ &imsic_cfg.mmios[i].size);
+ if ( rc )
+ {
+ printk(XENLOG_ERR "%s: unable to parse MMIO regset %d\n",
+ node->name, i);
+ goto imsic_init_err;
+ }
+
+ base_addr = imsic_cfg.mmios[i].base_addr;
+ base_addr &= ~(BIT(imsic_cfg.guest_index_bits +
+ imsic_cfg.hart_index_bits +
+ IMSIC_MMIO_PAGE_SHIFT, UL) - 1);
+ base_addr &= ~((BIT(imsic_cfg.group_index_bits, UL) - 1) <<
+ imsic_cfg.group_index_shift);
+ if ( base_addr != imsic_cfg.base_addr )
+ {
+ rc = -EINVAL;
+ printk(XENLOG_ERR "%s: address mismatch for regset %d\n",
+ node->name, i);
+ goto imsic_init_err;
+ }
+ }
+
+ /* Configure handlers for target CPUs */
+ for ( int i = 0; i < nr_parent_irqs; i++ )
+ {
+ rc = imsic_get_parent_hartid(node, i, &hartid);
+ if ( rc )
+ {
+ printk(XENLOG_WARNING "%s: hart ID for parent irq%d not found\n",
+ node->name, i);
+ continue;
+ }
+
+ if ( hartid > NR_CPUS )
+ {
+ printk(XENLOG_WARNING "%s: unsupported hart ID=%lu for parent
irq%d\n",
+ node->name, hartid, i);
+ continue;
+ }
+
+ /* Find MMIO location of MSI page */
+ index = imsic_cfg.nr_mmios;
+ reloff = i * BIT(imsic_cfg.guest_index_bits, UL) * IMSIC_MMIO_PAGE_SZ;
+ for ( int j = 0; imsic_cfg.nr_mmios; j++ )
+ {
+ if ( reloff < imsic_cfg.mmios[j].size )
+ {
+ index = j;
+ break;
+ }
+
+ /*
+ * MMIO region size may not be aligned to
+ * BIT(global->guest_index_bits) * IMSIC_MMIO_PAGE_SZ
+ * if holes are present.
+ */
+ reloff -= ROUNDUP(imsic_cfg.mmios[j].size,
+ BIT(imsic_cfg.guest_index_bits, UL) * IMSIC_MMIO_PAGE_SZ);
+ }
+
+ if ( index >= imsic_cfg.nr_mmios )
+ {
+ printk(XENLOG_WARNING "%s: MMIO not found for parent irq%d\n",
+ node->name, i);
+ continue;
+ }
+
+ if ( !IS_ALIGNED(imsic_cfg.msi[hartid].base_addr + reloff, PAGE_SIZE) )
+ {
+ printk(XENLOG_WARNING "%s: MMIO address 0x%lx is not aligned on a
page\n",
+ node->name, imsic_cfg.msi[hartid].base_addr + reloff);
+ imsic_cfg.msi[hartid].offset = 0;
+ imsic_cfg.msi[hartid].base_addr = 0;
+ continue;
+ }
+
+ imsic_cfg.mmios[index].harts[hartid] = true;
+ imsic_cfg.msi[hartid].base_addr = imsic_cfg.mmios[index].base_addr;
+ imsic_cfg.msi[hartid].offset = reloff;
+ nr_handlers++;
+ }
+
+ if ( !nr_handlers )
+ {
+ printk(XENLOG_ERR "%s: No CPU handlers found\n", node->name);
+ rc = -ENODEV;
+ goto imsic_init_err;
+ }
+
+ return 0;
+
+imsic_init_err:
+ xfree(imsic_cfg.mmios);
+
+ return rc;
+}
diff --git a/xen/arch/riscv/include/asm/imsic.h
b/xen/arch/riscv/include/asm/imsic.h
new file mode 100644
index 0000000000..126e651863
--- /dev/null
+++ b/xen/arch/riscv/include/asm/imsic.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: MIT */
+
+/*
+ * xen/arch/riscv/imsic.h
+ *
+ * RISC-V Incoming MSI Controller support
+ *
+ * (c) 2023 Microchip Technology Inc.
+ */
+
+#ifndef ASM__RISCV__IMSIC_H
+#define ASM__RISCV__IMSIC_H
+
+#include <xen/types.h>
+
+#define IMSIC_MMIO_PAGE_SHIFT 12
+#define IMSIC_MMIO_PAGE_SZ (1UL << IMSIC_MMIO_PAGE_SHIFT)
+
+#define IMSIC_MIN_ID 63
+#define IMSIC_MAX_ID 2048
+
+struct imsic_msi {
+ paddr_t base_addr;
+ unsigned long offset;
+};
+
+struct imsic_mmios {
+ paddr_t base_addr;
+ unsigned long size;
+ bool harts[NR_CPUS];
+};
+
+struct imsic_config {
+ /* base address */
+ paddr_t base_addr;
+
+ /* Bits representing Guest index, HART index, and Group index */
+ unsigned int guest_index_bits;
+ unsigned int hart_index_bits;
+ unsigned int group_index_bits;
+ unsigned int group_index_shift;
+
+ /* imsic phandle */
+ unsigned int phandle;
+
+ /* number of parent irq */
+ unsigned int nr_parent_irqs;
+
+ /* number off interrupt identities */
+ unsigned int nr_ids;
+
+ /* mmios */
+ unsigned int nr_mmios;
+ struct imsic_mmios *mmios;
+
+ /* MSI */
+ struct imsic_msi msi[NR_CPUS];
+};
+
+struct dt_device_node;
+int imsic_init(struct dt_device_node *n);
+
+struct imsic_config;
+const struct imsic_config *imsic_get_config(void);
+
+#endif /* ASM__RISCV__IMSIC_H */
--
2.49.0
