MLK-20373-5 serial: serial_xen: support normal uboot console

Support output/input using `xl console [domid]`.

Signed-off-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Flynn xu <flynn.xu@nxp.com>
(cherry picked from commit 75a9833506aa13c1d5a8641c81ac951c41ced55e)
(cherry picked from commit 5a495c39679b6641d369fc0c9cfdadafd8a408f6)
(cherry picked from commit 6f3cc8513ac1afe0cf679422ae82c4a5930a8c64)

2 files changed, 181 insertions, 28 deletions

diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig
index 21597b7234..31cf28e864 100644
--- a/drivers/serial/Kconfig
+++ b/drivers/serial/Kconfig
@@ -187,6 +187,9 @@ choice
 	depends on DEBUG_UART
 	default DEBUG_UART_NS16550
 
+config DEBUG_UART_XEN
+	bool "debug uart xen"
+
 config DEBUG_UART_ALTERA_JTAGUART
 	bool "Altera JTAG UART"
 	help
@@ -394,6 +397,7 @@ config DEBUG_UART_BASE
 	hex "Base address of UART"
 	depends on DEBUG_UART
 	default 0 if DEBUG_UART_SANDBOX
+	default 0 if DEBUG_UART_XEN
 	help
 	  This is the base address of your UART for memory-mapped UARTs.
 
@@ -404,6 +408,7 @@ config DEBUG_UART_CLOCK
 	int "UART input clock"
 	depends on DEBUG_UART
 	default 0 if DEBUG_UART_SANDBOX
+	default 0 if DEBUG_UART_XEN
 	help
 	  The UART input clock determines the speed of the internal UART
 	  circuitry. The baud rate is derived from this by dividing the input
diff --git a/drivers/serial/serial_xen.c b/drivers/serial/serial_xen.c
index ce0c36319b..416d0ac191 100644
--- a/drivers/serial/serial_xen.c
+++ b/drivers/serial/serial_xen.c
@@ -5,66 +5,214 @@
  */
 
 #include <common.h>
+#include <debug_uart.h>
 #include <dm.h>
 #include <errno.h>
+#include <fdtdec.h>
+#include <linux/compiler.h>
 #include <serial.h>
 
-extern void xenprintf(const char *buf);
-extern void xenprintc(const char c);
-#ifndef CONFIG_DM_SERIAL
+#include <xen/events.h>
+#include <xen/hvm.h>
+#include <xen/interface/sched.h>
+#include <xen/interface/hvm/hvm_op.h>
+#include <xen/interface/hvm/params.h>
+#include <xen/interface/io/console.h>
+#include <xen/interface/io/ring.h>
 
-static void xen_debug_serial_putc(const char c)
+DECLARE_GLOBAL_DATA_PTR;
+
+#ifdef CONFIG_DM_SERIAL
+struct xen_uart_priv {
+	struct xencons_interface *intf;
+	u32 evtchn;
+	int vtermno;
+	struct hvc_struct *hvc;
+	grant_ref_t gntref;
+};
+
+int xen_serial_setbrg(struct udevice *dev, int baudrate)
 {
-	/* If \n, also do \r */
-	if (c == '\n')
-		serial_putc('\r');
+	return 0;
+}
 
-	xenprintc(c);
+static int xen_serial_probe(struct udevice *dev)
+{
+	struct xen_uart_priv *priv = dev_get_priv(dev);
+	u64 v = 0;
+	unsigned long gfn;
+	int r;
+
+	r = hvm_get_parameter(HVM_PARAM_CONSOLE_EVTCHN, &v);
+	if (r < 0 || v == 0)
+		return r;
+
+	priv->evtchn = v;
+
+	r = hvm_get_parameter(HVM_PARAM_CONSOLE_PFN, &v);
+	if (r < 0 || v == 0)
+		return -ENODEV;
+
+	gfn = v;
+
+	priv->intf = (struct xencons_interface *)(gfn << XEN_PAGE_SHIFT);
+	if (!priv->intf)
+		return -EINVAL;
+
+	return 0;
 }
 
-static void xen_debug_serial_puts(const char *buf)
+static int xen_serial_pending(struct udevice *dev, bool input)
 {
-	xenprintf(buf);
+	struct xen_uart_priv *priv = dev_get_priv(dev);
+	struct xencons_interface *intf = priv->intf;
+
+	if (!input || intf->in_cons == intf->in_prod)
+		return 0;
+
+	return 1;
 }
 
-static int xen_debug_serial_start(void)
+static int xen_serial_getc(struct udevice *dev)
 {
-	return 0;
+	struct xen_uart_priv *priv = dev_get_priv(dev);
+	struct xencons_interface *intf = priv->intf;
+	XENCONS_RING_IDX cons;
+	char c;
+
+	while (intf->in_cons == intf->in_prod) {
+		mb(); /* wait */
+	}
+
+	cons = intf->in_cons;
+	mb();			/* get pointers before reading ring */
+
+	c = intf->in[MASK_XENCONS_IDX(cons++, intf->in)];
+
+	mb();			/* read ring before consuming */
+	intf->in_cons = cons;
+
+	notify_remote_via_evtchn(priv->evtchn);
+
+	return c;
 }
 
-static void xen_debug_serial_setbrg(void)
+static int __write_console(struct udevice *dev, const char *data, int len)
 {
+	struct xen_uart_priv *priv = dev_get_priv(dev);
+	struct xencons_interface *intf = priv->intf;
+	XENCONS_RING_IDX cons, prod;
+	int sent = 0;
+
+	cons = intf->out_cons;
+	prod = intf->out_prod;
+	mb(); /* Update pointer */
+
+	WARN_ON((prod - cons) > sizeof(intf->out));
+
+	while ((sent < len) && ((prod - cons) < sizeof(intf->out)))
+		intf->out[MASK_XENCONS_IDX(prod++, intf->out)] = data[sent++];
+
+	mb(); /* Update data before pointer */
+	intf->out_prod = prod;
+
+	if (sent)
+		notify_remote_via_evtchn(priv->evtchn);
 
+	if (data[sent - 1] == '\n')
+		serial_puts("\r");
+
+	return sent;
+}
+
+static int write_console(struct udevice *dev, const char *data, int len)
+{
+	/*
+	 * Make sure the whole buffer is emitted, polling if
+	 * necessary.  We don't ever want to rely on the hvc daemon
+	 * because the most interesting console output is when the
+	 * kernel is crippled.
+	 */
+	while (len) {
+		int sent = __write_console(dev, data, len);
+
+		data += sent;
+		len -= sent;
+
+		if (unlikely(len))
+			HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
+	}
+
+	return 0;
 }
 
-static int xen_debug_serial_getc(void)
+static int xen_serial_puts(struct udevice *dev, const char *str)
 {
+#ifdef CONFIG_SPL_BUILD
+	(void)HYPERVISOR_console_io(CONSOLEIO_write, strlen(str), str);
+#else
+	write_console(dev, str, strlen(str));
+#endif
+
 	return 0;
 }
 
-static int xen_debug_serial_tstc(void)
+static int xen_serial_putc(struct udevice *dev, const char ch)
 {
+#ifdef CONFIG_SPL_BUILD
+	(void)HYPERVISOR_console_io(CONSOLEIO_write, 1, &ch);
+#else
+	write_console(dev, &ch, 1);
+#endif
+
 	return 0;
 }
 
-static struct serial_device xen_debug_serial_drv = {
-	.name	= "xen_debug_serial",
-	.start	= xen_debug_serial_start,
-	.stop	= NULL,
-	.setbrg	= xen_debug_serial_setbrg,
-	.putc	= xen_debug_serial_putc,
-	.puts	= xen_debug_serial_puts,
-	.getc	= xen_debug_serial_getc,
-	.tstc	= xen_debug_serial_tstc,
+static const struct dm_serial_ops xen_serial_ops = {
+	.puts = xen_serial_puts,
+	.putc = xen_serial_putc,
+	.getc = xen_serial_getc,
+	.pending = xen_serial_pending,
+};
+
+static const struct udevice_id xen_serial_ids[] = {
+	{ .compatible = "xen,xen" },
+	{ }
 };
 
-void xen_debug_serial_initialize(void)
+U_BOOT_DRIVER(serial_xen) = {
+	.name	= "serial_xen",
+	.id	= UCLASS_SERIAL,
+	.of_match = xen_serial_ids,
+	.priv_auto_alloc_size = sizeof(struct xen_uart_priv),
+	.probe = xen_serial_probe,
+	.ops	= &xen_serial_ops,
+	.flags = DM_FLAG_PRE_RELOC | DM_FLAG_IGNORE_DEFAULT_CLKS,
+};
+#else
+__weak struct serial_device *default_serial_console(void)
 {
-	serial_register(&xen_debug_serial_drv);
+	return NULL;
 }
 
-__weak struct serial_device *default_serial_console(void)
+#endif
+
+#ifdef CONFIG_DEBUG_UART_XEN
+void _debug_uart_init(void)
+{
+}
+
+void _debug_uart_putc(int ch)
 {
-	return &xen_debug_serial_drv;
+	/* If \n, also do \r */
+	if (ch == '\n')
+		serial_putc('\r');
+
+	(void)HYPERVISOR_console_io(CONSOLEIO_write, 1, &ch);
+
+	return;
 }
+
+DEBUG_UART_FUNCS
+
 #endif