[Xen-changelog] [xen master] xen/arm: vpl011: Add a pl011 uart DT node in the guest device tree

[patchbot@xxxxxxx]

commit 499c9acdaacb6346f1cf8f0f9ed812a17eb60333
Author:     Bhupinder Thakur <bhupinder.thakur@xxxxxxxxxx>
AuthorDate: Wed Sep 27 11:43:33 2017 +0530
Commit:     Stefano Stabellini <sstabellini@xxxxxxxxxx>
CommitDate: Tue Oct 3 15:23:37 2017 -0700

    xen/arm: vpl011: Add a pl011 uart DT node in the guest device tree
    
    The SBSA UART node format is as specified in
    Documentation/devicetree/bindings/serial/arm_sbsa_uart.txt and given below:
    
    ARM SBSA defined generic UART
    ------------------------------
    This UART uses a subset of the PL011 registers and consequently lives
    in the PL011 driver. It's baudrate and other communication parameters
    cannot be adjusted at runtime, so it lacks a clock specifier here.
    
    Required properties:
    - compatible: must be "arm,sbsa-uart"
    - reg: exactly one register range
    - interrupts: exactly one interrupt specifier
    - current-speed: the (fixed) baud rate set by the firmware
    
    Currently the baud rate of 115200 has been selected as a default value,
    which is one of the valid baud rate settings. Higher baud rate was
    selected since an emulated pl011 can support any valid baud rate without
    any limitation of the hardware.
    
    Signed-off-by: Bhupinder Thakur <bhupinder.thakur@xxxxxxxxxx>
    Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>
    Acked-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 tools/libxl/libxl_arm.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/tools/libxl/libxl_arm.c b/tools/libxl/libxl_arm.c
index 6f5bc3c..de1840b 100644
--- a/tools/libxl/libxl_arm.c
+++ b/tools/libxl/libxl_arm.c
@@ -43,11 +43,38 @@ int libxl__arch_domain_prepare_config(libxl__gc *gc,
 {
     uint32_t nr_spis = 0;
     unsigned int i;
+    uint32_t vuart_irq;
+    bool vuart_enabled = false;
+
+    /*
+     * If pl011 vuart is enabled then increment the nr_spis to allow allocation
+     * of SPI VIRQ for pl011.
+     */
+    if (d_config->b_info.arch_arm.vuart == LIBXL_VUART_TYPE_SBSA_UART) {
+        nr_spis += (GUEST_VPL011_SPI - 32) + 1;
+        vuart_irq = GUEST_VPL011_SPI;
+        vuart_enabled = true;
+    }
 
     for (i = 0; i < d_config->b_info.num_irqs; i++) {
         uint32_t irq = d_config->b_info.irqs[i];
         uint32_t spi;
 
+        /*
+         * This check ensures the if user has requested pass-through of a 
certain irq
+         * which conflicts with vpl011 irq then it flags an error to indicate 
to the
+         * user that the specific HW irq cannot be used as it is dedicated for 
vpl011.
+         * 
+         * TODO:
+         * The vpl011 irq should be assigned such that it never conflicts with 
user
+         * specified irqs thereby preventing its pass-through. This TODO is for
+         * implementing that logic in future.
+         */
+        if (vuart_enabled && irq == vuart_irq) {
+            LOG(ERROR, "Physical IRQ %u conflicting with pl011 SPI\n", irq);
+            return ERROR_FAIL;
+        }
+
         if (irq < 32)
             continue;
 
@@ -590,6 +617,38 @@ static int make_hypervisor_node(libxl__gc *gc, void *fdt,
     return 0;
 }
 
+static int make_vpl011_uart_node(libxl__gc *gc, void *fdt,
+                                 const struct arch_info *ainfo,
+                                 struct xc_dom_image *dom)
+{
+    int res;
+    gic_interrupt intr;
+
+    res = fdt_begin_node(fdt, "sbsa-pl011");
+    if (res) return res;
+
+    res = fdt_property_compat(gc, fdt, 1, "arm,sbsa-uart");
+    if (res) return res;
+
+    res = fdt_property_regs(gc, fdt, ROOT_ADDRESS_CELLS, ROOT_SIZE_CELLS,
+                            1,
+                            GUEST_PL011_BASE, GUEST_PL011_SIZE);
+    if (res) return res;
+
+    set_interrupt(intr, GUEST_VPL011_SPI, 0xf, DT_IRQ_TYPE_LEVEL_HIGH);
+
+    res = fdt_property_interrupts(gc, fdt, &intr, 1);
+    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;
+}
+
 static const struct arch_info *get_arch_info(libxl__gc *gc,
                                              const struct xc_dom_image *dom)
 {
@@ -889,6 +948,9 @@ next_resize:
         FDT( make_timer_node(gc, fdt, ainfo, xc_config->clock_frequency) );
         FDT( make_hypervisor_node(gc, fdt, vers) );
 
+        if (info->arch_arm.vuart == LIBXL_VUART_TYPE_SBSA_UART)
+            FDT( make_vpl011_uart_node(gc, fdt, ainfo, dom) );
+
         if (pfdt)
             FDT( copy_partial_fdt(gc, fdt, pfdt) );
 
--
generated by git-patchbot for /home/xen/git/xen.git#master

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