[PATCH v2 15/21] 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 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 | 90 +++++++++++++++++++++++++++++++++++++--------
 1 file changed, 75 insertions(+), 15 deletions(-)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 48a91ad..718be48 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -519,17 +519,17 @@ static int write_properties(struct domain *d, struct kernel_info *kinfo,
 
 typedef __be32 gic_interrupt_t[3];
 
-static void set_interrupt_ppi(gic_interrupt_t interrupt, unsigned int irq,
-                              unsigned int cpumask, unsigned int level)
+static void set_interrupt(gic_interrupt_t interrupt, unsigned int irq,
+                          unsigned int cpumask, unsigned int level)
 {
     __be32 *cells = interrupt;
+    int 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);
 }
 
@@ -648,7 +648,7 @@ static int 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;
@@ -924,15 +924,15 @@ static int 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 )
@@ -1503,9 +1503,9 @@ static int 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 )
@@ -1520,12 +1520,63 @@ static int make_timer_domU_node(const struct domain *d, void *fdt)
     return res;
 }
 
+#ifdef CONFIG_SBSA_VUART_CONSOLE
+static int 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.
  */
 #define DOMU_DTB_SIZE 4096
-static int prepare_dtb_domU(struct domain *d, struct kernel_info *kinfo)
+static int prepare_dtb_domU(struct domain *d, struct kernel_info *kinfo,
+                            bool vpl011)
 {
     int addrcells, sizecells;
     int ret;
@@ -1585,6 +1636,15 @@ static int prepare_dtb_domU(struct domain *d, struct kernel_info *kinfo)
     if ( ret )
         goto err;
 
+#ifdef CONFIG_SBSA_VUART_CONSOLE
+    if ( vpl011 )
+    {
+        ret = make_vpl011_uart_node(d, kinfo->fdt, addrcells, sizecells);
+        if ( ret )
+            goto err;
+    }
+#endif
+
     ret = fdt_end_node(kinfo->fdt);
     if ( ret < 0 )
         goto err;
@@ -2467,7 +2527,7 @@ static int __init construct_domU(struct domain *d, struct dt_device_node *node)
     d->arch.type = kinfo.type;
     allocate_memory(d, &kinfo);
 
-    rc = prepare_dtb_domU(d, &kinfo);
+    rc = prepare_dtb_domU(d, &kinfo, vpl011);
     if ( rc < 0 )
         return rc;
 
-- 
1.9.1


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