Add tweaks to work in Mambo simulator

Mambo doesn't implement various things such as PBA SCOMs, LPC,
ChipTOD, etc... It also provides a special console hook.

This adds detection of Mambo via the /mambo node, and enables
us to boot all the way to Linux.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Stewart Smith <stewart@linux.vnet.ibm.com>

13 files changed, 123 insertions, 18 deletions

diff --git a/asm/misc.S b/asm/misc.S
index 00c7f78..bbabebc 100644
--- a/asm/misc.S
+++ b/asm/misc.S
@@ -50,3 +50,22 @@ _mcount:
 	mflr	%r4
 	b	__mcount_stack_check
 #endif
+
+.global mambo_read
+mambo_read:
+#define SIM_READ_CONSOLE_CODE 60
+	li	%r3,SIM_READ_CONSOLE_CODE
+	.long	0x000eaeb0
+	extsw	%r3,%r3
+	blr
+
+.global mambo_write
+mambo_write:
+#define SIM_WRITE_CONSOLE_CODE 0
+	li	%r6,0
+	mr	%r5,%r4
+	mr	%r4,%r3
+	li	%r3,SIM_WRITE_CONSOLE_CODE
+	.long	0x000eaeb0
+	blr
+
diff --git a/core/chip.c b/core/chip.c
index 272f024..b805fe1 100644
--- a/core/chip.c
+++ b/core/chip.c
@@ -20,6 +20,7 @@
 #include <device.h>
 
 static struct proc_chip *chips[MAX_CHIPS];
+bool is_mambo_chip;
 
 uint32_t pir_to_chip_id(uint32_t pir)
 {
@@ -66,6 +67,10 @@ void init_chips(void)
 	struct proc_chip *chip;
 	struct dt_node *xn;
 
+	/* Detect mambo chip */
+	if (dt_find_by_path(dt_root, "/mambo"))
+		is_mambo_chip = true;
+
 	/* We walk the chips based on xscom nodes in the tree */
 	dt_for_each_compatible(dt_root, xn, "ibm,xscom") {
 		uint32_t id = dt_get_chip_id(xn);
diff --git a/core/console.c b/core/console.c
index 111d64f..d24a4b4 100644
--- a/core/console.c
+++ b/core/console.c
@@ -59,20 +59,47 @@ void force_dummy_console(void)
 	dt_add_property(dt_chosen, "sapphire,enable-dummy-console", NULL, 0);
 }
 
-#ifdef MAMBO_CONSOLE
-static void mambo_write(const char *buf, size_t count)
+
+static int mambo_char = -1;
+
+static bool mambo_con_poll_read(void)
 {
-#define SIM_WRITE_CONSOLE_CODE	0
-	register int c asm("r3") = 0; /* SIM_WRITE_CONSOLE_CODE */
-	register unsigned long a1 asm("r4") = (unsigned long)buf;
-	register unsigned long a2 asm("r5") = count;
-	register unsigned long a3 asm("r6") = 0;
-	asm volatile (".long 0x000eaeb0":"=r" (c):"r"(c), "r"(a1), "r"(a2),
-		      "r"(a3));
+	if (mambo_char < 0)
+		mambo_char = mambo_read();
+	return mambo_char >= 0;
+}
+
+static size_t mambo_con_read(char *buf, size_t len)
+{
+	size_t count = 0;
+
+	while(count < len) {
+		if (!mambo_con_poll_read())
+			break;
+		*(buf++) = mambo_char;
+		mambo_char = -1;
+		count++;
+	}
+	return count;
+}
+
+static size_t mambo_con_write(const char *buf, size_t len)
+{
+	mambo_write(buf, len);
+	return len;
+}
+
+static struct con_ops mambo_con_driver = {
+	.poll_read = mambo_con_poll_read,
+	.read = mambo_con_read,
+	.write = mambo_con_write,
+};
+
+void enable_mambo_console(void)
+{
+	prlog(PR_NOTICE, "Enabling Mambo console\n");
+	set_console(&mambo_con_driver);
 }
-#else
-static void mambo_write(const char *buf __unused, size_t count __unused) { }
-#endif /* MAMBO_CONSOLE */
 
 void clear_console(void)
 {
@@ -213,7 +240,9 @@ static size_t inmem_read(char *buf, size_t req)
 
 static void write_char(char c)
 {
+#ifdef MAMBO_DEBUG_CONSOLE
 	mambo_write(&c, 1);
+#endif
 	inmem_write(c);
 }
 
@@ -306,6 +335,7 @@ static int64_t dummy_console_read(int64_t term_number, int64_t *length,
 	if (term_number != 0)
 		return OPAL_PARAMETER;
 	*length = read(0, buffer, *length);
+	opal_update_pending_evt(OPAL_EVENT_CONSOLE_INPUT, 0);
 
 	return OPAL_SUCCESS;
 }
@@ -313,8 +343,14 @@ opal_call(OPAL_CONSOLE_READ, dummy_console_read, 3);
 
 static void dummy_console_poll(void *data __unused)
 {
+	bool has_data = false;
+
 	lock(&con_lock);
+	if (con_driver && con_driver->poll_read)
+		has_data = con_driver->poll_read;
 	if (memcons.in_prod != memcons.in_cons)
+		has_data = true;
+	if (has_data)
 		opal_update_pending_evt(OPAL_EVENT_CONSOLE_INPUT,
 					OPAL_EVENT_CONSOLE_INPUT);
 	else
@@ -325,6 +361,7 @@ static void dummy_console_poll(void *data __unused)
 void dummy_console_add_nodes(void)
 {
 	struct dt_node *con, *consoles;
+	struct dt_property *p;
 
 	consoles = dt_new(opal_node, "consoles");
 	assert(consoles);
@@ -338,6 +375,11 @@ void dummy_console_add_nodes(void)
 	dt_add_property_cells(con, "reg", 0);
 	dt_add_property_string(con, "device_type", "serial");
 
+	/* Mambo might have left a crap one, clear it */
+	p = __dt_find_property(dt_chosen, "linux,stdout-path");
+	if (p)
+		dt_del_property(dt_chosen, p);
+
 	dt_add_property_string(dt_chosen, "linux,stdout-path",
 			       "/ibm,opal/consoles/serial@0");
 
diff --git a/core/init.c b/core/init.c
index d8e9d20..6eeaa0d 100644
--- a/core/init.c
+++ b/core/init.c
@@ -293,7 +293,7 @@ static bool load_kernel(void)
 	}
 
 	if (!ksize)
-		printf("Assuming kernel at 0x%p\n", KERNEL_LOAD_BASE);
+		printf("Assuming kernel at %p\n", KERNEL_LOAD_BASE);
 
 	printf("INIT: Kernel loaded, size: %zu bytes (0 = unknown preload)\n",
 	       ksize);
@@ -537,6 +537,8 @@ void __noreturn main_cpu_entry(const void *fdt, u32 master_cpu)
 	 * to access chips via that path early on.
 	 */
 	init_chips();
+	if (is_mambo_chip)
+		enable_mambo_console();
 	xscom_init();
 	mfsi_init();
 
diff --git a/core/platform.c b/core/platform.c
index 1b0093d..53971e9 100644
--- a/core/platform.c
+++ b/core/platform.c
@@ -50,6 +50,7 @@ opal_call(OPAL_CEC_REBOOT, opal_cec_reboot, 0);
 
 static void generic_platform_init(void)
 {
+	force_dummy_console();
 	fake_rtc_init();
 }
 
diff --git a/hw/chiptod.c b/hw/chiptod.c
index 865ff82..daa67ef 100644
--- a/hw/chiptod.c
+++ b/hw/chiptod.c
@@ -19,6 +19,7 @@
  */
 #include <skiboot.h>
 #include <chiptod.h>
+#include <chip.h>
 #include <xscom.h>
 #include <io.h>
 #include <cpu.h>
@@ -528,6 +529,9 @@ static void chiptod_sync_slave(void *data)
 
 bool chiptod_wakeup_resync(void)
 {
+	if (chiptod_primary < 0)
+		return 0;
+
 	lock(&chiptod_lock);
 
 	/* Apply base tfmr */
@@ -634,6 +638,9 @@ int chiptod_recover_tb_errors(void)
 	uint64_t tfmr;
 	int rc = 1;
 
+	if (chiptod_primary < 0)
+		return 0;
+
 	lock(&chiptod_lock);
 
 	/* Get fresh copy of TFMR */
@@ -774,6 +781,10 @@ void chiptod_init(u32 master_cpu)
 	struct cpu_thread *cpu0, *cpu;
 	bool sres;
 
+	/* Mambo doesn't simulate the chiptod */
+	if (is_mambo_chip)
+		return;
+
 	op_display(OP_LOG, OP_MOD_CHIPTOD, 0);
 
 	if (!chiptod_probe(master_cpu)) {
diff --git a/hw/homer.c b/hw/homer.c
index b8e51c5..6145e25 100644
--- a/hw/homer.c
+++ b/hw/homer.c
@@ -111,7 +111,7 @@ void homer_init(void)
 {
 	struct proc_chip *chip;
 
-	if (proc_gen != proc_gen_p8)
+	if (proc_gen != proc_gen_p8 || 	is_mambo_chip)
 		return;
 
 	/*
diff --git a/hw/occ.c b/hw/occ.c
index 5b3c3a6..e1eaf30 100644
--- a/hw/occ.c
+++ b/hw/occ.c
@@ -510,6 +510,9 @@ static struct fsp_client fsp_occ_client = {
 
 void occ_send_dummy_interrupt(void)
 {
+	/* Mambo chip doesn't do this */
+	if (is_mambo_chip)
+		return;
 	xscom_writeme(OCB_OCI_OCCMISC_OR,
 		      OCB_OCI_OCIMISC_IRQ |
 		      OCB_OCI_OCIMISC_IRQ_OPAL_DUMMY);
diff --git a/hw/slw.c b/hw/slw.c
index 68228a9..b72a0aa 100644
--- a/hw/slw.c
+++ b/hw/slw.c
@@ -513,6 +513,12 @@ static void add_cpu_idle_state_properties(void)
 		return;
 	}
 
+	/* Mambo currently misbehaves in nap mode vs. timebase, so let's
+	 * disable idle states
+	 */
+	if (is_mambo_chip)
+		return;
+
 	/*
 	 * Chose the right state table for the chip
 	 *
diff --git a/hw/xscom.c b/hw/xscom.c
index 98cbaec..1698135 100644
--- a/hw/xscom.c
+++ b/hw/xscom.c
@@ -435,9 +435,15 @@ int xscom_writeme(uint64_t pcb_addr, uint64_t val)
 static void xscom_init_chip_info(struct proc_chip *chip)
 {
 	uint64_t val;
-	int64_t rc;
+	int64_t rc = 0;
 
-	rc = xscom_read(chip->id, 0xf000f, &val);
+	/* Mambo chip model lacks the f000f register, just make
+	 * something up (Murano DD2.1)
+	 */
+	if (is_mambo_chip)
+		val = 0x221EF04980000000;
+	else
+		rc = xscom_read(chip->id, 0xf000f, &val);
 	if (rc) {
 		prerror("XSCOM: Error %lld reading 0xf000f register\n", rc);
 		/* We leave chip type to UNKNOWN */
diff --git a/include/chip.h b/include/chip.h
index fb2771e..83671fa 100644
--- a/include/chip.h
+++ b/include/chip.h
@@ -139,6 +139,9 @@ struct proc_chip {
 	struct list_head	i2cms;
 };
 
+/* Mambo simplified chip model lacks some features, handle it here */
+extern bool is_mambo_chip;
+
 extern uint32_t pir_to_chip_id(uint32_t pir);
 extern uint32_t pir_to_core_id(uint32_t pir);
 extern uint32_t pir_to_thread_id(uint32_t pir);
diff --git a/include/config.h b/include/config.h
index 78b63fe..2524570 100644
--- a/include/config.h
+++ b/include/config.h
@@ -52,8 +52,10 @@
 //#define OPAL_DEBUG_CONSOLE_IO	1
 //#define OPAL_DEBUG_CONSOLE_POLL	1
 
-/* Enable this for mambo console */
-//#define MAMBO_CONSOLE		1
+/* Enable this to force all writes to the in-memory console to
+ * be mirrored on the mambo console
+ */
+//#define MAMBO_DEBUG_CONSOLE		1
 
 /* Enable this to hookup SkiBoot log to the DVS console */
 #define DVS_CONSOLE		1
diff --git a/include/console.h b/include/console.h
index bbe2444..5b6c5d5 100644
--- a/include/console.h
+++ b/include/console.h
@@ -50,6 +50,7 @@ extern struct memcons memcons;
 struct con_ops {
 	size_t (*write)(const char *buf, size_t len);
 	size_t (*read)(char *buf, size_t len);
+	bool (*poll_read)(void);
 };
 
 extern struct lock con_lock;
@@ -60,6 +61,10 @@ extern bool flush_console(void);
 extern bool __flush_console(bool flush_to_drivers);
 extern void set_console(struct con_ops *driver);
 
+extern int mambo_read(void);
+extern void mambo_write(const char *buf, size_t count);
+extern void enable_mambo_console(void);
+
 ssize_t console_write(bool flush_to_drivers, const void *buf, size_t count);
 
 extern void clear_console(void);