Skiboot patches to fix scom error lockup
diff --git a/openpower/package/skiboot/skiboot-0003-xscom-remove-recursive-locking.patch b/openpower/package/skiboot/skiboot-0003-xscom-remove-recursive-locking.patch
new file mode 100644
index 0000000..e71e17e
--- /dev/null
+++ b/openpower/package/skiboot/skiboot-0003-xscom-remove-recursive-locking.patch
@@ -0,0 +1,70 @@
+diff --git a/hw/xscom.c b/hw/xscom.c
+index 6bd71a3..a3533be 100644
+--- a/hw/xscom.c
++++ b/hw/xscom.c
+@@ -342,7 +342,6 @@ static uint32_t xscom_decode_chiplet(uint32_t partid, uint64_t *pcb_addr)
+ */
+ int xscom_read(uint32_t partid, uint64_t pcb_addr, uint64_t *val)
+ {
+- bool need_unlock;
+ uint32_t gcid;
+ int rc;
+
+@@ -360,12 +359,8 @@ int xscom_read(uint32_t partid, uint64_t pcb_addr, uint64_t *val)
+ return OPAL_PARAMETER;
+ }
+
+- /*
+- * HW822317 requires locking. We use a recursive lock as error
+- * conditions might cause printf's which might then try to take
+- * the lock again
+- */
+- need_unlock = lock_recursive(&xscom_lock);
++ /* HW822317 requires us to do global locking */
++ lock(&xscom_lock);
+
+ /* Direct vs indirect access */
+ if (pcb_addr & XSCOM_ADDR_IND_FLAG)
+@@ -374,8 +369,7 @@ int xscom_read(uint32_t partid, uint64_t pcb_addr, uint64_t *val)
+ rc = __xscom_read(gcid, pcb_addr & 0x7fffffff, val);
+
+ /* Unlock it */
+- if (need_unlock)
+- unlock(&xscom_lock);
++ unlock(&xscom_lock);
+ return rc;
+ }
+
+@@ -383,7 +377,6 @@ opal_call(OPAL_XSCOM_READ, xscom_read, 3);
+
+ int xscom_write(uint32_t partid, uint64_t pcb_addr, uint64_t val)
+ {
+- bool need_unlock;
+ uint32_t gcid;
+ int rc;
+
+@@ -401,12 +394,8 @@ int xscom_write(uint32_t partid, uint64_t pcb_addr, uint64_t val)
+ return OPAL_PARAMETER;
+ }
+
+- /*
+- * HW822317 requires locking. We use a recursive lock as error
+- * conditions might cause printf's which might then try to take
+- * the lock again
+- */
+- need_unlock = lock_recursive(&xscom_lock);
++ /* HW822317 requires us to do global locking */
++ lock(&xscom_lock);
+
+ /* Direct vs indirect access */
+ if (pcb_addr & XSCOM_ADDR_IND_FLAG)
+@@ -415,8 +404,7 @@ int xscom_write(uint32_t partid, uint64_t pcb_addr, uint64_t val)
+ rc = __xscom_write(gcid, pcb_addr & 0x7fffffff, val);
+
+ /* Unlock it */
+- if (need_unlock)
+- unlock(&xscom_lock);
++ unlock(&xscom_lock);
+ return rc;
+ }
+ opal_call(OPAL_XSCOM_WRITE, xscom_write, 3);
diff --git a/openpower/package/skiboot/skiboot-0004-Add-xscom_ok-and-lpc_ok-to-check-XSCOM-and-LPC-usability.patch b/openpower/package/skiboot/skiboot-0004-Add-xscom_ok-and-lpc_ok-to-check-XSCOM-and-LPC-usability.patch
new file mode 100644
index 0000000..f19f6aa
--- /dev/null
+++ b/openpower/package/skiboot/skiboot-0004-Add-xscom_ok-and-lpc_ok-to-check-XSCOM-and-LPC-usability.patch
@@ -0,0 +1,117 @@
+diff --git a/hw/bt.c b/hw/bt.c
+index 7bf1b2f..8bb44cd 100644
+--- a/hw/bt.c
++++ b/hw/bt.c
+@@ -350,7 +350,8 @@ static void print_debug_queue_info(void) {}
+
+ static void bt_send_and_unlock(void)
+ {
+- if (bt.state == BT_STATE_IDLE && !list_empty(&bt.msgq))
++ if (lpc_ok() &&
++ bt.state == BT_STATE_IDLE && !list_empty(&bt.msgq))
+ bt_send_msg();
+
+ unlock(&bt.lock);
+@@ -361,6 +362,10 @@ static void bt_poll(struct timer *t __unused, void *data __unused)
+ {
+ uint8_t bt_ctrl;
+
++ /* Don't do anything if the LPC bus is offline */
++ if (!lpc_ok())
++ return;
++
+ /* If we can't get the lock assume someone else will notice
+ * the new message and process it. */
+ lock(&bt.lock);
+@@ -440,7 +445,9 @@ static int bt_add_ipmi_msg(struct ipmi_msg *ipmi_msg)
+
+ void bt_irq(void)
+ {
+- uint8_t ireg = bt_inb(BT_INTMASK);
++ uint8_t ireg;
++
++ ireg = bt_inb(BT_INTMASK);
+
+ bt.irq_ok = true;
+ if (ireg & BT_INTMASK_B2H_IRQ) {
+diff --git a/hw/lpc-uart.c b/hw/lpc-uart.c
+index 2e6114a..7c3190e 100644
+--- a/hw/lpc-uart.c
++++ b/hw/lpc-uart.c
+@@ -135,6 +135,10 @@ static size_t uart_con_write(const char *buf, size_t len)
+ {
+ size_t written = 0;
+
++ /* If LPC bus is bad, we just swallow data */
++ if (!lpc_ok())
++ return written;
++
+ lock(&uart_lock);
+ while(written < len) {
+ if (tx_room == 0) {
+diff --git a/hw/lpc.c b/hw/lpc.c
+index 0db674f..b287020 100644
+--- a/hw/lpc.c
++++ b/hw/lpc.c
+@@ -500,3 +500,15 @@ void lpc_used_by_console(void)
+ unlock(&chip->lpc_lock);
+ }
+ }
++
++bool lpc_ok(void)
++{
++ struct proc_chip *chip;
++
++ if (lpc_default_chip_id < 0)
++ return false;
++ if (!xscom_ok())
++ return false;
++ chip = get_chip(lpc_default_chip_id);
++ return !lock_held_by_me(&chip->lpc_lock);
++}
+diff --git a/hw/xscom.c b/hw/xscom.c
+index a3533be..07b9b94 100644
+--- a/hw/xscom.c
++++ b/hw/xscom.c
+@@ -531,3 +531,8 @@ void xscom_used_by_console(void)
+ lock(&xscom_lock);
+ unlock(&xscom_lock);
+ }
++
++bool xscom_ok(void)
++{
++ return !lock_held_by_me(&xscom_lock);
++}
+diff --git a/include/lpc.h b/include/lpc.h
+index 5611c54..a0990fd 100644
+--- a/include/lpc.h
++++ b/include/lpc.h
+@@ -27,6 +27,12 @@ extern void lpc_init(void);
+ /* Check for a default bus */
+ extern bool lpc_present(void);
+
++/* Return of LPC is currently usable. This can be false if the caller
++ * currently holds a lock that would make it unsafe, or the LPC bus
++ * is known to be in some error condition (TBI).
++ */
++extern bool lpc_ok(void);
++
+ /* Handle the interrupt from LPC source */
+ extern void __attrconst lpc_interrupt(uint32_t chip_id);
+
+diff --git a/include/xscom.h b/include/xscom.h
+index b1ecaf5..a841261 100644
+--- a/include/xscom.h
++++ b/include/xscom.h
+@@ -173,6 +173,11 @@ extern void xscom_init(void);
+ /* Mark XSCOM lock as being in console path */
+ extern void xscom_used_by_console(void);
+
++/* Returns true if XSCOM can be used. Typically this returns false if
++ * the current CPU holds the XSCOM lock (to avoid re-entrancy from error path).
++ */
++extern bool xscom_ok(void);
++
+ extern int64_t xscom_read_cfam_chipid(uint32_t partid, uint32_t *chip_id);
+
+ #endif /* __XSCOM_H */