[PATCH v3 19/25] xen/arm: generate vpl011 node on device tree for domU

[Stefano Stabellini <sstabellini@kernel.org>]

Introduce vpl011 support to guests started from Xen: it provides a
simple way to print output from a guest, as most guests come with a
pl011 driver. It is also able to provide a working console with
interrupt support.

The UART exposed to the guest is a SBSA compatible UART and not a PL011.
SBSA UART is a subset of PL011 r1p5. A full PL011 implementation in Xen
would just be too difficult, so guests may require some drivers changes.

Enable vpl011 conditionally if the user requested it.

Make set_interrupt_ppi able to handle non-PPI and rename it
set_interrupt.

Signed-off-by: Stefano Stabellini <stefanos@xilinx.com>
---
Changes in v3:
- use bool
- retain BUG_ON(irq < 16)
- add vpl011 bool to kinfo
- return error of vpl011 is required but CONFIG_SBSA_VUART_CONSOLE is
  missing

Changes in v2:
- code style fixes
- make set_interrupt_ppi generic
- rename set_interrupt_ppi to set_interrupt
- only make the vpl011 node if the option was enabled
---
 xen/arch/arm/domain_build.c | 95 ++++++++++++++++++++++++++++++++++++++-------
 xen/arch/arm/kernel.h       |  3 ++
 2 files changed, 83 insertions(+), 15 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 167a56e..f9fa484 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -619,19 +619,20 @@ static int __init write_properties(struct domain *d, struct kernel_info *kinfo,
 
 typedef __be32 gic_interrupt_t[3];
 
-static void __init set_interrupt_ppi(gic_interrupt_t interrupt,
-                                     unsigned int irq,
-                                     unsigned int cpumask,
-                                     unsigned int level)
+static void __init set_interrupt(gic_interrupt_t interrupt,
+                                 unsigned int irq,
+                                 unsigned int cpumask,
+                                 unsigned int level)
 {
     __be32 *cells = interrupt;
+    bool is_ppi = !!(irq < 32);
 
     BUG_ON(irq < 16);
-    BUG_ON(irq >= 32);
+    irq -= (is_ppi) ? 16: 32; /* PPIs start at 16, SPIs at 32 */
 
     /* See linux Documentation/devicetree/bindings/interrupt-controller/arm,gic.txt */
-    dt_set_cell(&cells, 1, 1); /* is a PPI */
-    dt_set_cell(&cells, 1, irq - 16); /* PPIs start at 16 */
+    dt_set_cell(&cells, 1, is_ppi); /* is a PPI? */
+    dt_set_cell(&cells, 1, irq);
     dt_set_cell(&cells, 1, (cpumask << 8) | level);
 }
 
@@ -752,7 +753,7 @@ static int __init make_hypervisor_node(struct domain *d,
      *  - All CPUs
      *  TODO: Handle properly the cpumask;
      */
-    set_interrupt_ppi(intr, d->arch.evtchn_irq, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
+    set_interrupt(intr, d->arch.evtchn_irq, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
     res = fdt_property_interrupts(fdt, &intr, 1);
     if ( res )
         return res;
@@ -1029,15 +1030,15 @@ static int __init make_timer_node(const struct domain *d, void *fdt,
 
     irq = timer_get_irq(TIMER_PHYS_SECURE_PPI);
     dt_dprintk("  Secure interrupt %u\n", irq);
-    set_interrupt_ppi(intrs[0], irq, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
+    set_interrupt(intrs[0], irq, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
 
     irq = timer_get_irq(TIMER_PHYS_NONSECURE_PPI);
     dt_dprintk("  Non secure interrupt %u\n", irq);
-    set_interrupt_ppi(intrs[1], irq, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
+    set_interrupt(intrs[1], irq, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
 
     irq = timer_get_irq(TIMER_VIRT_PPI);
     dt_dprintk("  Virt interrupt %u\n", irq);
-    set_interrupt_ppi(intrs[2], irq, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
+    set_interrupt(intrs[2], irq, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
 
     res = fdt_property_interrupts(fdt, intrs, 3);
     if ( res )
@@ -1605,9 +1606,9 @@ static int __init make_timer_domU_node(const struct domain *d, void *fdt)
             return res;
     }
 
-    set_interrupt_ppi(intrs[0], GUEST_TIMER_PHYS_S_PPI, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
-    set_interrupt_ppi(intrs[1], GUEST_TIMER_PHYS_NS_PPI, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
-    set_interrupt_ppi(intrs[2], GUEST_TIMER_VIRT_PPI, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
+    set_interrupt(intrs[0], GUEST_TIMER_PHYS_S_PPI, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
+    set_interrupt(intrs[1], GUEST_TIMER_PHYS_NS_PPI, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
+    set_interrupt(intrs[2], GUEST_TIMER_VIRT_PPI, 0xf, DT_IRQ_TYPE_LEVEL_LOW);
 
     res = fdt_property(fdt, "interrupts", intrs, sizeof (intrs[0]) * 3);
     if ( res )
@@ -1622,6 +1623,56 @@ static int __init make_timer_domU_node(const struct domain *d, void *fdt)
     return res;
 }
 
+#ifdef CONFIG_SBSA_VUART_CONSOLE
+static int __init make_vpl011_uart_node(const struct domain *d, void *fdt,
+                                 int addrcells, int sizecells)
+{
+    int res;
+    gic_interrupt_t intr;
+    int reg_size = addrcells + sizecells;
+    int nr_cells = reg_size;
+    __be32 reg[nr_cells];
+    __be32 *cells;
+
+    res = fdt_begin_node(fdt, "sbsa-pl011");
+    if ( res )
+        return res;
+
+    res = fdt_property_string(fdt, "compatible", "arm,sbsa-uart");
+    if ( res )
+        return res;
+
+    cells = &reg[0];
+    dt_child_set_range(&cells, addrcells, sizecells, GUEST_PL011_BASE,
+                       GUEST_PL011_SIZE);
+    if ( res )
+        return res;
+    res = fdt_property(fdt, "reg", reg, sizeof(reg));
+    if ( res )
+        return res;
+
+    set_interrupt(intr, GUEST_VPL011_SPI, 0xf, DT_IRQ_TYPE_LEVEL_HIGH);
+
+    res = fdt_property(fdt, "interrupts", intr, sizeof (intr));
+    if ( res )
+        return res;
+
+    res = fdt_property_cell(fdt, "interrupt-parent",
+                            GUEST_PHANDLE_GIC);
+    if ( res )
+        return res;
+
+    /* Use a default baud rate of 115200. */
+    fdt_property_u32(fdt, "current-speed", 115200);
+
+    res = fdt_end_node(fdt);
+    if ( res )
+        return res;
+
+    return 0;
+}
+#endif
+
 /*
  * The max size for DT is 2MB. However, the generated DT is small, 4KB
  * are enough for now, but we might have to increase it in the feature.
@@ -1683,6 +1734,18 @@ static int __init prepare_dtb_domU(struct domain *d, struct kernel_info *kinfo)
     if ( ret )
         goto err;
 
+    if ( kinfo->vpl011 )
+    {
+#ifdef CONFIG_SBSA_VUART_CONSOLE
+        ret = make_vpl011_uart_node(d, kinfo->fdt, addrcells, sizecells);
+        if ( ret )
+            goto err;
+#else
+        ret = -EINVAL;
+        goto err;
+#endif
+    }
+
     ret = fdt_end_node(kinfo->fdt);
     if ( ret < 0 )
         goto err;
@@ -2537,7 +2600,7 @@ static int __init construct_domU(struct domain *d, struct dt_device_node *node)
 {
     struct kernel_info kinfo = {};
     int rc;
-    u32 mem;
+    u32 mem, len;
 
     printk("*** LOADING DOMU ***\n");
 
@@ -2550,6 +2613,8 @@ static int __init construct_domU(struct domain *d, struct dt_device_node *node)
         return -EINVAL;
     kinfo.unassigned_mem = (paddr_t)mem << 10;
 
+    kinfo.vpl011 = dt_get_property(node, "vpl011", &len) != NULL;
+
     d->vcpu = xzalloc_array(struct vcpu *, d->max_vcpus);
     if ( !d->vcpu )
         return -ENOMEM;;
diff --git a/xen/arch/arm/kernel.h b/xen/arch/arm/kernel.h
index 4a65289..9c9e568 100644
--- a/xen/arch/arm/kernel.h
+++ b/xen/arch/arm/kernel.h
@@ -33,6 +33,9 @@ struct kernel_info {
     paddr_t dtb_paddr;
     paddr_t initrd_paddr;
 
+    /* Enable pl011 emulation */
+    bool vpl011;
+
     /* loader to use for this kernel */
     void (*load)(struct kernel_info *info);
     /* loader specific state */
-- 
1.9.1


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