[Skiboot] [PATCH v2 4/5] xscom: Add indirect form 1 scoms

[Michael Neuling]

Add code to perform indirect form 1 scoms.

POWER8 does form 0 only. POWER9 adds form 1. The form is determined
from the address only. Hardware only allows writes for form 1.

Only hostboot uses these scoms during IPL, so they are unused by
skiboot currently.

Signed-off-by: Michael Neuling <mikey at neuling.org>
---
 hw/xscom.c      | 49 +++++++++++++++++++++++++++++++++++++++++++++++--
 include/xscom.h |  1 +
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/hw/xscom.c b/hw/xscom.c
index b0bc260087..9fb7da6d3d 100644
--- a/hw/xscom.c
+++ b/hw/xscom.c
@@ -317,7 +317,8 @@ static int __xscom_write(uint32_t gcid, uint32_t pcb_addr, uint64_t val)
 /*
  * Indirect XSCOM access functions
  */
-static int xscom_indirect_read(uint32_t gcid, uint64_t pcb_addr, uint64_t *val)
+static int xscom_indirect_read_form0(uint32_t gcid, uint64_t pcb_addr,
+				     uint64_t *val)
 {
 	uint32_t addr;
 	uint64_t data;
@@ -360,7 +361,23 @@ static int xscom_indirect_read(uint32_t gcid, uint64_t pcb_addr, uint64_t *val)
 	return rc;
 }
 
-static int xscom_indirect_write(uint32_t gcid, uint64_t pcb_addr, uint64_t val)
+static int xscom_indirect_form(uint64_t pcb_addr)
+{
+	return (pcb_addr >> 60) & 1;
+}
+
+static int xscom_indirect_read(uint32_t gcid, uint64_t pcb_addr, uint64_t *val)
+{
+	uint64_t form = xscom_indirect_form(pcb_addr);
+
+	if ((proc_gen == proc_gen_p9) && (form == 1))
+		return OPAL_UNSUPPORTED;
+
+	return xscom_indirect_read_form0(gcid, pcb_addr, val);
+}
+
+static int xscom_indirect_write_form0(uint32_t gcid, uint64_t pcb_addr,
+				      uint64_t val)
 {
 	uint32_t addr;
 	uint64_t data;
@@ -402,6 +419,34 @@ static int xscom_indirect_write(uint32_t gcid, uint64_t pcb_addr, uint64_t val)
 	return rc;
 }
 
+static int xscom_indirect_write_form1(uint32_t gcid, uint64_t pcb_addr,
+				      uint64_t val)
+{
+	uint32_t addr;
+	uint64_t data;
+
+	if (proc_gen < proc_gen_p9)
+		return OPAL_UNSUPPORTED;
+	if (val & ~(XSCOM_DATA_IND_FORM1_DATA))
+		return OPAL_PARAMETER;
+
+	/* Mangle address and data for form1 */
+	addr = (pcb_addr & 0x000ffffffff);
+	data = (pcb_addr & 0xfff00000000) << 20;
+	data |= val;
+	return __xscom_write(gcid, addr, data);
+}
+
+static int xscom_indirect_write(uint32_t gcid, uint64_t pcb_addr, uint64_t val)
+{
+	uint64_t form = xscom_indirect_form(pcb_addr);
+
+	if ((proc_gen == proc_gen_p9) && (form == 1))
+		return xscom_indirect_write_form1(gcid, pcb_addr, val);
+
+	return xscom_indirect_write_form0(gcid, pcb_addr, val);
+}
+
 static uint32_t xscom_decode_chiplet(uint32_t partid, uint64_t *pcb_addr)
 {
 	uint32_t gcid = (partid & 0x0fffffff) >> 4;
diff --git a/include/xscom.h b/include/xscom.h
index bad9140cf7..871d210d18 100644
--- a/include/xscom.h
+++ b/include/xscom.h
@@ -192,6 +192,7 @@
 #define XSCOM_DATA_IND_COMPLETE		PPC_BIT(32)
 #define XSCOM_DATA_IND_ERR		PPC_BITMASK(33,35)
 #define XSCOM_DATA_IND_DATA		PPC_BITMASK(48,63)
+#define XSCOM_DATA_IND_FORM1_DATA	PPC_BITMASK(12,63)
 
 /* HB folks say: try 10 time for now */
 #define XSCOM_IND_MAX_RETRIES		10
-- 
2.9.3