[PATCH v8 14/26] emul/vuart: add global UART emulator configuration knob

[dmukhin@xxxxxxxx]

From: Denis Mukhin <dmukhin@xxxxxxxx>

Introduce new command line setting `vuart=domid[:compatible,name]` for
configuring UART emulator per given domain.

Only one domain is supported for now.

Format:
  domid      - vUART owner domain ID
  compatible - vUART compatible string, must match with one of the
               registered emulators
  name       - vUART user-friendly name used for searching for one of
               the pre-defined guest I/O resources

compatible string and name are optional, if skipped, platform default
values will be chosen.

Note, documentation update is not covered in this patch.

Signed-off-by: Denis Mukhin <dmukhin@xxxxxxxx>
---
 xen/common/emul/vuart/vuart.c | 85 +++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)

diff --git a/xen/common/emul/vuart/vuart.c b/xen/common/emul/vuart/vuart.c
index bd3b756fb4d6..0df29540b1b6 100644
--- a/xen/common/emul/vuart/vuart.c
+++ b/xen/common/emul/vuart/vuart.c
@@ -6,8 +6,10 @@
 
 #include <asm/types.h>
 
+#include <xen/ctype.h>
 #include <xen/err.h>
 #include <xen/resource.h>
+#include <xen/param.h>
 #include <xen/sched.h>
 #include <xen/vuart.h>
 #include <xen/xvmalloc.h>
@@ -18,6 +20,89 @@
 extern const struct vuart_emulator vuart_array_start[];
 extern const struct vuart_emulator vuart_array_end[];
 
+static domid_t __read_mostly opt_vuart_domid = DOMID_INVALID;
+static const struct vuart_info * __read_mostly opt_vuart_info;
+
+static const struct vuart_info vuart_supported[] = {
+#define VUART(c,n,t,a,s,i) { \
+    .compatible = c, \
+    .name = n, \
+    .flags = VUART_CONSOLE_INPUT, \
+    .base_type = t, \
+    .base_addr = a, \
+    .size = s, \
+    .irq = i, \
+}
+#ifdef CONFIG_VUART_NS16X50
+        VUART("ns16550", "com1", IORESOURCE_IO, 0x3f8u, 8u, 4u),
+        VUART("ns16550", "com2", IORESOURCE_IO, 0x2f8u, 8u, 3u),
+        VUART("ns16550", "com3", IORESOURCE_IO, 0x3feu, 8u, 4u),
+        VUART("ns16550", "com4", IORESOURCE_IO, 0x2feu, 8u, 3u),
+#endif /* CONFIG_VUART_NS16X50 */
+#undef VUART
+};
+
+static int __init cf_check vuart_parse_cmdline(const char *s)
+{
+    const char *compat = "ns16550";
+    size_t compat_len = strlen(compat);
+    const char *name = "com1";
+    size_t name_len = strlen(name);
+    const char *end;
+    domid_t domid;
+    unsigned int i;
+
+    /* vuart=domid:compatible,name */
+    if ( !isdigit(*s) )
+        return -EINVAL;
+
+    domid = simple_strtoul(s, &end, 0);
+    if ( domid >= DOMID_FIRST_RESERVED )
+        return -EINVAL;
+
+    if ( *end == '\0' )
+        goto match_defaults;
+
+    if ( *end != ':' )
+        return -EINVAL;
+
+    compat = end + 1;
+
+    while ( *end && *end != ',' )
+        end++;
+    if ( *end != ',' )
+        return -EINVAL;
+
+    compat_len = end - compat;
+    if ( !compat_len )
+        return -EINVAL;
+
+    name = end + 1;
+    name_len = strlen(name);
+    if ( !name_len )
+        return -EINVAL;
+
+ match_defaults:
+    for ( i = 0; i < ARRAY_SIZE(vuart_supported); i++ )
+    {
+        if ( compat_len != strlen(vuart_supported[i].compatible) ||
+             strncmp(compat, vuart_supported[i].compatible, compat_len) )
+            continue;
+
+        if ( name_len != strlen(vuart_supported[i].name) ||
+             strncmp(name, vuart_supported[i].name, name_len) )
+            continue;
+
+        opt_vuart_info = &vuart_supported[i];
+        opt_vuart_domid = domid;
+
+        return 0;
+    }
+
+    return -EINVAL;
+}
+custom_param("vuart", vuart_parse_cmdline);
+
 static const struct vuart_emulator *
 vuart_match_by_compatible(const struct domain *d, const char *compat)
 {
-- 
2.56.0