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>

6 files changed, 43 insertions, 42 deletions

diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index e41a3818b240..0576e1d8c4f9 100644
--- a/arch/tile/Kconfig
+++ b/arch/tile/Kconfig
@@ -112,6 +112,7 @@ config SMP
 config HVC_TILE
 	depends on TTY
 	select HVC_DRIVER
+	select HVC_IRQ if TILEGX
 	def_bool y
 
 config TILEGX
diff --git a/arch/tile/include/asm/setup.h b/arch/tile/include/asm/setup.h
index d048888c5d9a..e98909033e5b 100644
--- a/arch/tile/include/asm/setup.h
+++ b/arch/tile/include/asm/setup.h
@@ -24,9 +24,8 @@
  */
 #define MAXMEM_PFN	PFN_DOWN(MAXMEM)
 
+int tile_console_write(const char *buf, int count);
 void early_panic(const char *fmt, ...);
-void warn_early_printk(void);
-void __init disable_early_printk(void);
 
 /* Init-time routine to do tile-specific per-cpu setup. */
 void setup_cpu(int boot);
diff --git a/arch/tile/include/hv/hypervisor.h b/arch/tile/include/hv/hypervisor.h
index 837dca5328c2..f882ebcf43a9 100644
--- a/arch/tile/include/hv/hypervisor.h
+++ b/arch/tile/include/hv/hypervisor.h
@@ -318,8 +318,11 @@
 /** hv_set_pte_super_shift */
 #define HV_DISPATCH_SET_PTE_SUPER_SHIFT           57
 
+/** hv_console_set_ipi */
+#define HV_DISPATCH_CONSOLE_SET_IPI               63
+
 /** One more than the largest dispatch value */
-#define _HV_DISPATCH_END                          58
+#define _HV_DISPATCH_END                          64
 
 
 #ifndef __ASSEMBLER__
@@ -585,6 +588,30 @@ typedef struct
  */
 int hv_get_ipi_pte(HV_Coord tile, int pl, HV_PTE* pte);
 
+/** Configure the console interrupt.
+ *
+ * When the console client interrupt is enabled, the hypervisor will
+ * deliver the specified IPI to the client in the following situations:
+ *
+ * - The console has at least one character available for input.
+ *
+ * - The console can accept new characters for output, and the last call
+ *   to hv_console_write() did not write all of the characters requested
+ *   by the client.
+ *
+ * Note that in some system configurations, console interrupt will not
+ * be available; clients should be prepared for this routine to fail and
+ * to fall back to periodic console polling in that case.
+ *
+ * @param ipi Index of the IPI register which will receive the interrupt.
+ * @param event IPI event number for console interrupt. If less than 0,
+ *        disable the console IPI interrupt.
+ * @param coord Tile to be targeted for console interrupt.
+ * @return 0 on success, otherwise, HV_EINVAL if illegal parameter,
+ *         HV_ENOTSUP if console interrupt are not available.
+ */
+int hv_console_set_ipi(int ipi, int event, HV_Coord coord);
+
 #else /* !CHIP_HAS_IPI() */
 
 /** A set of interrupts. */
diff --git a/arch/tile/kernel/early_printk.c b/arch/tile/kernel/early_printk.c
index 34d72a151bf3..b608e00e7f6d 100644
--- a/arch/tile/kernel/early_printk.c
+++ b/arch/tile/kernel/early_printk.c
@@ -23,19 +23,24 @@
 
 static void early_hv_write(struct console *con, const char *s, unsigned n)
 {
-	hv_console_write((HV_VirtAddr) s, n);
+	tile_console_write(s, n);
+
+	/*
+	 * Convert NL to NLCR (close enough to CRNL) during early boot.
+	 * We assume newlines are at the ends of strings, which turns out
+	 * to be good enough for early boot console output.
+	 */
+	if (n && s[n-1] == '\n')
+		tile_console_write("\r", 1);
 }
 
 static struct console early_hv_console = {
 	.name =		"earlyhv",
 	.write =	early_hv_write,
-	.flags =	CON_PRINTBUFFER,
+	.flags =	CON_PRINTBUFFER | CON_BOOT,
 	.index =	-1,
 };
 
-/* Direct interface for emergencies */
-static int early_console_complete;
-
 void early_panic(const char *fmt, ...)
 {
 	va_list ap;
@@ -43,51 +48,21 @@ void early_panic(const char *fmt, ...)
 	va_start(ap, fmt);
 	early_printk("Kernel panic - not syncing: ");
 	early_vprintk(fmt, ap);
-	early_console->write(early_console, "\n", 1);
+	early_printk("\n");
 	va_end(ap);
 	dump_stack();
 	hv_halt();
 }
 
-static int __initdata keep_early;
-
 static int __init setup_early_printk(char *str)
 {
 	if (early_console)
 		return 1;
 
-	if (str != NULL && strncmp(str, "keep", 4) == 0)
-		keep_early = 1;
-
 	early_console = &early_hv_console;
 	register_console(early_console);
 
 	return 0;
 }
 
-void __init disable_early_printk(void)
-{
-	early_console_complete = 1;
-	if (!early_console)
-		return;
-	if (!keep_early) {
-		early_printk("disabling early console\n");
-		unregister_console(early_console);
-		early_console = NULL;
-	} else {
-		early_printk("keeping early console\n");
-	}
-}
-
-void warn_early_printk(void)
-{
-	if (early_console_complete || early_console)
-		return;
-	early_printk("\
-Machine shutting down before console output is fully initialized.\n\
-You may wish to reboot and add the option 'earlyprintk' to your\n\
-boot command line to see any diagnostic early console output.\n\
-");
-}
-
 early_param("earlyprintk", setup_early_printk);
diff --git a/arch/tile/kernel/hvglue.lds b/arch/tile/kernel/hvglue.lds
index d44c5a67a1ed..ef522900633a 100644
--- a/arch/tile/kernel/hvglue.lds
+++ b/arch/tile/kernel/hvglue.lds
@@ -56,4 +56,5 @@ hv_inquire_realpa = TEXT_OFFSET + 0x106c0;
 hv_flush_all = TEXT_OFFSET + 0x106e0;
 hv_get_ipi_pte = TEXT_OFFSET + 0x10700;
 hv_set_pte_super_shift = TEXT_OFFSET + 0x10720;
-hv_glue_internals = TEXT_OFFSET + 0x10740;
+hv_console_set_ipi = TEXT_OFFSET + 0x107e0;
+hv_glue_internals = TEXT_OFFSET + 0x10800;
diff --git a/arch/tile/kernel/reboot.c b/arch/tile/kernel/reboot.c
index d1b5c913ae72..6c5d2c070a12 100644
--- a/arch/tile/kernel/reboot.c
+++ b/arch/tile/kernel/reboot.c
@@ -27,7 +27,6 @@
 
 void machine_halt(void)
 {
-	warn_early_printk();
 	arch_local_irq_disable_all();
 	smp_send_stop();
 	hv_halt();
@@ -35,7 +34,6 @@ void machine_halt(void)
 
 void machine_power_off(void)
 {
-	warn_early_printk();
 	arch_local_irq_disable_all();
 	smp_send_stop();
 	hv_power_off();