[Skiboot] [PATCH] hw/lpc: Fix firmware memory space access for devices > 0

[Nicholas Piggin]

The LPC firmware memory space is 256MB in size, and it may select
up to 16 devices with the IDSEL field.

OPB addresses FW space as a 32-bit value with the top 4 bit selecting
the device and the bottom 28 addressing the FW memory space. Therefore
the top bits should ignored when calculating the offset into the FW
window.

Fix this by allowing lpc_opb_prepare() to adjust the address directly
and correctly mask it. Now there's no need to return opb_base to the
caller either, fold that in at the same time.

Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
---
 hw/lpc.c | 33 ++++++++++++++++++++-------------
 1 file changed, 20 insertions(+), 13 deletions(-)

diff --git a/hw/lpc.c b/hw/lpc.c
index 398528084..36a63a5af 100644
--- a/hw/lpc.c
+++ b/hw/lpc.c
@@ -389,9 +389,11 @@ static int64_t lpc_set_fw_rdsz(struct lpcm *lpc, uint8_t rdsz)
 
 static int64_t lpc_opb_prepare(struct lpcm *lpc,
 			       enum OpalLPCAddressType addr_type,
-			       uint32_t addr, uint32_t sz,
-			       uint32_t *opb_base, bool is_write)
+			       uint32_t *addrp, uint32_t sz,
+			       bool is_write)
 {
+	uint32_t addr = *addrp;
+	uint32_t opb_base;
 	uint32_t top = addr + sz;
 	uint8_t fw_idsel;
 	int64_t rc;
@@ -412,7 +414,7 @@ static int64_t lpc_opb_prepare(struct lpcm *lpc,
 		/* And only supports byte accesses */
 		if (sz != 1)
 			return OPAL_PARAMETER;
-		*opb_base = lpc_io_opb_base;
+		opb_base = lpc_io_opb_base;
 		break;
 	case OPAL_LPC_MEM:
 		/* MEM space is 256M */
@@ -421,18 +423,20 @@ static int64_t lpc_opb_prepare(struct lpcm *lpc,
 		/* And only supports byte accesses */
 		if (sz != 1)
 			return OPAL_PARAMETER;
-		*opb_base = lpc_mem_opb_base;
+		opb_base = lpc_mem_opb_base;
 		break;
 	case OPAL_LPC_FW:
 		/*
 		 * FW space is in segments of 256M controlled
 		 * by IDSEL, make sure we don't cross segments
 		 */
-		*opb_base = lpc_fw_opb_base;
 		fw_idsel = (addr >> 28);
 		if (((top - 1) >> 28) != fw_idsel)
 			return OPAL_PARAMETER;
 
+		opb_base = lpc_fw_opb_base;
+		addr = addr & 0x0fffffff;
+
 		/* Set segment */
 		rc = lpc_set_fw_idsel(lpc, fw_idsel);
 		if (rc)
@@ -447,6 +451,9 @@ static int64_t lpc_opb_prepare(struct lpcm *lpc,
 	default:
 		return OPAL_PARAMETER;
 	}
+
+	*addrp = opb_base + addr;
+
 	return OPAL_SUCCESS;
 }
 
@@ -525,7 +532,6 @@ static int64_t __lpc_write(struct lpcm *lpc, enum OpalLPCAddressType addr_type,
 			   uint32_t addr, uint32_t data, uint32_t sz,
 			   bool probe)
 {
-	uint32_t opb_base;
 	int64_t rc;
 
 	lock(&lpc->lock);
@@ -537,14 +543,15 @@ static int64_t __lpc_write(struct lpcm *lpc, enum OpalLPCAddressType addr_type,
 
 	/*
 	 * Convert to an OPB access and handle LPC HC configuration
-	 * for FW accesses (IDSEL)
+	 * for FW accesses (IDSEL), and adjust the address to the
+	 * memory space.
 	 */
-	rc = lpc_opb_prepare(lpc, addr_type, addr, sz, &opb_base, true);
+	rc = lpc_opb_prepare(lpc, addr_type, &addr, sz, true);
 	if (rc)
 		goto bail;
 
 	/* Perform OPB access */
-	rc = opb_write(lpc, opb_base + addr, data, sz);
+	rc = opb_write(lpc, addr, data, sz);
 	if (rc)
 		goto bail;
 
@@ -612,7 +619,6 @@ static int64_t __lpc_read(struct lpcm *lpc, enum OpalLPCAddressType addr_type,
 			  uint32_t addr, uint32_t *data, uint32_t sz,
 			  bool probe)
 {
-	uint32_t opb_base;
 	int64_t rc;
 
 	lock(&lpc->lock);
@@ -624,14 +630,15 @@ static int64_t __lpc_read(struct lpcm *lpc, enum OpalLPCAddressType addr_type,
 
 	/*
 	 * Convert to an OPB access and handle LPC HC configuration
-	 * for FW accesses (IDSEL and read size)
+	 * for FW accesses (IDSEL and read size), and adjust the address
+	 * to the memory space.
 	 */
-	rc = lpc_opb_prepare(lpc, addr_type, addr, sz, &opb_base, false);
+	rc = lpc_opb_prepare(lpc, addr_type, &addr, sz, false);
 	if (rc)
 		goto bail;
 
 	/* Perform OPB access */
-	rc = opb_read(lpc, opb_base + addr, data, sz);
+	rc = opb_read(lpc, addr, data, sz);
 	if (rc)
 		goto bail;
 
-- 
2.47.1