[PATCH] tile: various console improvements

From: Chris Metcalf
Date: Wed Aug 07 2013 - 11:01:04 EST

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@xxxxxxxxxx>
---
arch/tile/Kconfig | 1 +
arch/tile/include/asm/setup.h | 3 +-
arch/tile/include/hv/hypervisor.h | 29 +++++++-
arch/tile/kernel/early_printk.c | 47 +++---------
arch/tile/kernel/hvglue.lds | 3 +-
arch/tile/kernel/reboot.c | 2 -
drivers/tty/hvc/hvc_tile.c | 149 ++++++++++++++++++++++++++++++++++++--
7 files changed, 186 insertions(+), 48 deletions(-)

diff --git a/arch/tile/Kconfig b/arch/tile/Kconfig
index e41a381..0576e1d 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 d048888..e989090 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 837dca5..f882ebc 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 34d72a1..b608e00 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 d44c5a6..ef52290 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 d1b5c91..6c5d2c0 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();
diff --git a/drivers/tty/hvc/hvc_tile.c b/drivers/tty/hvc/hvc_tile.c
index 7a84a05..af8cdaa 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);
--
1.8.3.1

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