tile: various console improvements

This change improves and cleans up the tile console.

- We enable HVC_IRQ support on tilegx, with the addition of a new
  Tilera hypervisor API for tilegx to allow a console IPI.  If IPI
  support is not available we fall back to the previous polling mode.

- We simplify the earlyprintk code to use CON_BOOT and eliminate some
  of the other supporting earlyprintk code.

- A new tile_console_write() primitive is used to send output to
  the console and is factored out of the hvc_tile driver.
  This lets us support a "sim_console" boot argument to allow using
  simulator hooks to send output to the "console" as a slightly
  faster alternative to emulating the hardware more directly.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 143 insertions, 6 deletions

diff --git a/drivers/tty/hvc/hvc_tile.c b/drivers/tty/hvc/hvc_tile.c
index 7a84a0595477..af8cdaa1dcb9 100644
--- a/drivers/tty/hvc/hvc_tile.c
+++ b/drivers/tty/hvc/hvc_tile.c
@@ -18,16 +18,46 @@
 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
 #include <linux/moduleparam.h>
+#include <linux/platform_device.h>
 #include <linux/types.h>
 
+#include <asm/setup.h>
+#include <arch/sim_def.h>
+
 #include <hv/hypervisor.h>
 
 #include "hvc_console.h"
 
+static int use_sim_console;
+static int __init sim_console(char *str)
+{
+        use_sim_console = 1;
+        return 0;
+}
+early_param("sim_console", sim_console);
+
+int tile_console_write(const char *buf, int count)
+{
+        if (unlikely(use_sim_console)) {
+                int i;
+                for (i = 0; i < count; ++i)
+                        __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_PUTC |
+                                     (buf[i] << _SIM_CONTROL_OPERATOR_BITS));
+                __insn_mtspr(SPR_SIM_CONTROL, SIM_CONTROL_PUTC |
+                             (SIM_PUTC_FLUSH_BINARY <<
+                              _SIM_CONTROL_OPERATOR_BITS));
+                return 0;
+        } else {
+                return hv_console_write((HV_VirtAddr)buf, count);
+        }
+}
+
 static int hvc_tile_put_chars(uint32_t vt, const char *buf, int count)
 {
-        return hv_console_write((HV_VirtAddr)buf, count);
+        return tile_console_write(buf, count);
 }
 
 static int hvc_tile_get_chars(uint32_t vt, char *buf, int count)
@@ -44,25 +74,132 @@ static int hvc_tile_get_chars(uint32_t vt, char *buf, int count)
         return i;
 }
 
+#ifdef __tilegx__
+/*
+ * IRQ based callbacks.
+ */
+static int hvc_tile_notifier_add_irq(struct hvc_struct *hp, int irq)
+{
+        int rc;
+        int cpu = raw_smp_processor_id();  /* Choose an arbitrary cpu */
+        HV_Coord coord = { .x = cpu_x(cpu), .y = cpu_y(cpu) };
+
+        rc = notifier_add_irq(hp, irq);
+        if (rc)
+                return rc;
+
+        /*
+         * Request that the hypervisor start sending us interrupts.
+         * If the hypervisor returns an error, we still return 0, so that
+         * we can fall back to polling.
+         */
+        if (hv_console_set_ipi(KERNEL_PL, irq, coord) < 0)
+                notifier_del_irq(hp, irq);
+
+        return 0;
+}
+
+static void hvc_tile_notifier_del_irq(struct hvc_struct *hp, int irq)
+{
+        HV_Coord coord = { 0, 0 };
+
+        /* Tell the hypervisor to stop sending us interrupts. */
+        hv_console_set_ipi(KERNEL_PL, -1, coord);
+
+        notifier_del_irq(hp, irq);
+}
+
+static void hvc_tile_notifier_hangup_irq(struct hvc_struct *hp, int irq)
+{
+        hvc_tile_notifier_del_irq(hp, irq);
+}
+#endif
+
 static const struct hv_ops hvc_tile_get_put_ops = {
         .get_chars = hvc_tile_get_chars,
         .put_chars = hvc_tile_put_chars,
+#ifdef __tilegx__
+        .notifier_add = hvc_tile_notifier_add_irq,
+        .notifier_del = hvc_tile_notifier_del_irq,
+        .notifier_hangup = hvc_tile_notifier_hangup_irq,
+#endif
+};
+
+
+#ifdef __tilegx__
+static int hvc_tile_probe(struct platform_device *pdev)
+{
+        struct hvc_struct *hp;
+        int tile_hvc_irq;
+
+        /* Create our IRQ and register it. */
+        tile_hvc_irq = create_irq();
+        if (tile_hvc_irq < 0)
+                return -ENXIO;
+
+        tile_irq_activate(tile_hvc_irq, TILE_IRQ_PERCPU);
+        hp = hvc_alloc(0, tile_hvc_irq, &hvc_tile_get_put_ops, 128);
+        if (IS_ERR(hp)) {
+                destroy_irq(tile_hvc_irq);
+                return PTR_ERR(hp);
+        }
+        dev_set_drvdata(&pdev->dev, hp);
+
+        return 0;
+}
+
+static int hvc_tile_remove(struct platform_device *pdev)
+{
+        int rc;
+        struct hvc_struct *hp = dev_get_drvdata(&pdev->dev);
+
+        rc = hvc_remove(hp);
+        if (rc == 0)
+                destroy_irq(hp->data);
+
+        return rc;
+}
+
+static void hvc_tile_shutdown(struct platform_device *pdev)
+{
+        struct hvc_struct *hp = dev_get_drvdata(&pdev->dev);
+
+        hvc_tile_notifier_del_irq(hp, hp->data);
+}
+
+static struct platform_device hvc_tile_pdev = {
+        .name           = "hvc-tile",
+        .id             = 0,
+};
+
+static struct platform_driver hvc_tile_driver = {
+        .probe          = hvc_tile_probe,
+        .remove         = hvc_tile_remove,
+        .shutdown       = hvc_tile_shutdown,
+        .driver         = {
+                .name   = "hvc-tile",
+                .owner  = THIS_MODULE,
+        }
 };
+#endif
 
 static int __init hvc_tile_console_init(void)
 {
-        extern void disable_early_printk(void);
         hvc_instantiate(0, 0, &hvc_tile_get_put_ops);
         add_preferred_console("hvc", 0, NULL);
-        disable_early_printk();
         return 0;
 }
 console_initcall(hvc_tile_console_init);
 
 static int __init hvc_tile_init(void)
 {
-        struct hvc_struct *s;
-        s = hvc_alloc(0, 0, &hvc_tile_get_put_ops, 128);
-        return IS_ERR(s) ? PTR_ERR(s) : 0;
+#ifndef __tilegx__
+        struct hvc_struct *hp;
+        hp = hvc_alloc(0, 0, &hvc_tile_get_put_ops, 128);
+        return IS_ERR(hp) ? PTR_ERR(hp) : 0;
+#else
+        platform_device_register(&hvc_tile_pdev);
+        return platform_driver_register(&hvc_tile_driver);
+#endif
 }
 device_initcall(hvc_tile_init);