[Xen-changelog] [xen staging] xen/arm: generate vpl011 node on device tree for domU

[p***@xen.org]

commit 6dcae49d99559b45144c419e03210d594520c940
Author: Stefano Stabellini <***@kernel.org>
AuthorDate: Tue Nov 13 09:49:32 2018 -0800
Commit: Julien Grall <***@arm.com>
CommitDate: Wed Nov 14 19:34:48 2018 +0000

xen/arm: generate vpl011 node on device tree for domU

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.

Signed-off-by: Stefano Stabellini <***@xilinx.com>
Acked-by: Julien Grall <***@arm.com>
---
xen/arch/arm/domain_build.c | 60 +++++++++++++++++++++++++++++++++++++++++++++
xen/arch/arm/kernel.h | 3 +++
2 files changed, 63 insertions(+)

diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c
index 8cc5655b8c..cd4a2c7de7 100644
--- a/xen/arch/arm/domain_build.c
+++ b/xen/arch/arm/domain_build.c
@@ -1622,6 +1622,54 @@ 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 res;
+ gic_interrupt_t intr;
+ __be32 reg[GUEST_ROOT_ADDRESS_CELLS + GUEST_ROOT_SIZE_CELLS];
+ __be32 *cells;
+
+ res = fdt_begin_node(fdt, "sbsa-uart@"__stringify(GUEST_PL011_BASE));
+ 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, GUEST_ROOT_ADDRESS_CELLS,
+ GUEST_ROOT_SIZE_CELLS, 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 future.
@@ -1683,6 +1731,16 @@ static int __init prepare_dtb_domU(struct domain *d, struct kernel_info *kinfo)
if ( ret )
goto err;

+ if ( kinfo->vpl011 )
+ {
+ ret = -EINVAL;
+#ifdef CONFIG_SBSA_VUART_CONSOLE
+ ret = make_vpl011_uart_node(d, kinfo->fdt);
+#endif
+ if ( ret )
+ goto err;
+ }
+
ret = fdt_end_node(kinfo->fdt);
if ( ret < 0 )
goto err;
@@ -2551,6 +2609,8 @@ static int __init construct_domU(struct domain *d,

printk("*** LOADING DOMU cpus=%u memory=%"PRIx64"KB ***\n", d->max_vcpus, mem);

+ kinfo.vpl011 = dt_property_read_bool(node, "vpl011");
+
if ( vcpu_create(d, 0, 0) == NULL )
return -ENOMEM;
d->max_pages = ~0U;
diff --git a/xen/arch/arm/kernel.h b/xen/arch/arm/kernel.h
index 4320f72ad4..33f3e72b11 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 */
--
generated by git-patchbot for /home/xen/git/xen.git#staging