opal-api: add endian conversions to most opal calls

This adds missing endian conversions to most calls, sufficient at least
to handle calls from a kernel booting on mambo.

Subsystems requiring more extensive changes (e.g., xive) will be done
with individual changes.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Vasant Hegde <hegdevasant@linux.vnet.ibm.com>
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>

13 files changed, 125 insertions, 74 deletions

diff --git a/hw/dts.c b/hw/dts.c
index 31b068b..c21c5c7 100644
--- a/hw/dts.c
+++ b/hw/dts.c
@@ -174,9 +174,9 @@ static void dts_async_read_temp(struct timer *t __unused, void *data,
 	rc = dts_read_core_temp_p9(cpu->pir, &dts);
 	if (!rc) {
 		if (cpu->sensor_attr == SENSOR_DTS_ATTR_TEMP_MAX)
-			*cpu->sensor_data = dts.temp;
+			*cpu->sensor_data = cpu_to_be64(dts.temp);
 		else if (cpu->sensor_attr == SENSOR_DTS_ATTR_TEMP_TRIP)
-			*cpu->sensor_data = dts.trip;
+			*cpu->sensor_data = cpu_to_be64(dts.trip);
 	}
 
 	if (!swkup_rc)
@@ -191,7 +191,7 @@ static void dts_async_read_temp(struct timer *t __unused, void *data,
 }
 
 static int dts_read_core_temp(u32 pir, struct dts *dts, u8 attr,
-			      int token, u64 *sensor_data)
+			      int token, __be64 *sensor_data)
 {
 	struct cpu_thread *cpu;
 	int rc;
@@ -286,7 +286,7 @@ enum sensor_dts_class {
  */
 #define centaur_get_id(rid) (0x80000000 | ((rid) & 0x3ff))
 
-int64_t dts_sensor_read(u32 sensor_hndl, int token, u64 *sensor_data)
+int64_t dts_sensor_read(u32 sensor_hndl, int token, __be64 *sensor_data)
 {
 	uint8_t	attr = sensor_get_attr(sensor_hndl);
 	uint32_t rid = sensor_get_rid(sensor_hndl);
@@ -313,9 +313,9 @@ int64_t dts_sensor_read(u32 sensor_hndl, int token, u64 *sensor_data)
 		return rc;
 
 	if (attr == SENSOR_DTS_ATTR_TEMP_MAX)
-		*sensor_data = dts.temp;
+		*sensor_data = cpu_to_be64(dts.temp);
 	else if (attr == SENSOR_DTS_ATTR_TEMP_TRIP)
-		*sensor_data = dts.trip;
+		*sensor_data = cpu_to_be64(dts.trip);
 
 	return 0;
 }
diff --git a/hw/fake-rtc.c b/hw/fake-rtc.c
index 328be97..fd2882d 100644
--- a/hw/fake-rtc.c
+++ b/hw/fake-rtc.c
@@ -34,13 +34,15 @@ static int64_t fake_rtc_write(uint32_t ymd, uint64_t hmsm)
 	return OPAL_SUCCESS;
 }
 
-static int64_t fake_rtc_read(uint32_t *ymd, uint64_t *hmsm)
+static int64_t fake_rtc_read(__be32 *__ymd, __be64 *__hmsm)
 {
 
 	time_t sec;
 	struct tm tm_calculated;
+	uint32_t ymd;
+	uint64_t hmsm;
 
-	if (!ymd || !hmsm)
+	if (!__ymd || !__hmsm)
 		return OPAL_PARAMETER;
 
 	/* Compute the emulated clock value */
@@ -48,10 +50,13 @@ static int64_t fake_rtc_read(uint32_t *ymd, uint64_t *hmsm)
 
 	sec = tb_to_secs(mftb() - tb_synctime) + mktime(&tm_offset);
 	gmtime_r(&sec, &tm_calculated);
-	tm_to_datetime(&tm_calculated, ymd, hmsm);
+	tm_to_datetime(&tm_calculated, &ymd, &hmsm);
 
 	unlock(&emulation_lock);
 
+	*__ymd = cpu_to_be32(ymd);
+	*__hmsm = cpu_to_be64(hmsm);
+
 	return OPAL_SUCCESS;
 }
 
diff --git a/hw/fsp/fsp-console.c b/hw/fsp/fsp-console.c
index 1a2ecab..624efb4 100644
--- a/hw/fsp/fsp-console.c
+++ b/hw/fsp/fsp-console.c
@@ -579,7 +579,7 @@ void fsp_console_preinit(void)
 
 }
 
-static int64_t fsp_console_write(int64_t term_number, int64_t *length,
+static int64_t fsp_console_write(int64_t term_number, __be64 *__length,
 				 const uint8_t *buffer)
 {
 	struct fsp_serial *fs;
@@ -596,7 +596,7 @@ static int64_t fsp_console_write(int64_t term_number, int64_t *length,
 		return OPAL_CLOSED;
 	}
 	/* Clamp to a reasonable size */
-	requested = *length;
+	requested = be64_to_cpu(*__length);
 	if (requested > 0x1000)
 		requested = 0x1000;
 	written = fsp_write_vserial(fs, buffer, requested);
@@ -618,7 +618,7 @@ static int64_t fsp_console_write(int64_t term_number, int64_t *length,
 	      buffer[6], buffer[6], buffer[7], buffer[7]);
 #endif /* OPAL_DEBUG_CONSOLE_IO */
 
-	*length = written;
+	*__length = cpu_to_be64(written);
 	unlock(&fsp_con_lock);
 
 	if (written)
@@ -628,11 +628,12 @@ static int64_t fsp_console_write(int64_t term_number, int64_t *length,
 }
 
 static int64_t fsp_console_write_buffer_space(int64_t term_number,
-					      int64_t *length)
+					      __be64 *__length)
 {
 	static bool elog_generated = false;
 	struct fsp_serial *fs;
 	struct fsp_serbuf_hdr *sb;
+	int64_t length;
 
 	if (term_number < 0 || term_number >= MAX_SERIAL)
 		return OPAL_PARAMETER;
@@ -645,15 +646,16 @@ static int64_t fsp_console_write_buffer_space(int64_t term_number,
 		return OPAL_CLOSED;
 	}
 	sb = fs->out_buf;
-	*length = (sb->next_out + SER_BUF_DATA_SIZE - sb->next_in - 1)
+	length = (sb->next_out + SER_BUF_DATA_SIZE - sb->next_in - 1)
 		% SER_BUF_DATA_SIZE;
 	unlock(&fsp_con_lock);
 
 	/* Console buffer has enough space to write incoming data */
-	if (*length != fs->out_buf_prev_len) {
-		fs->out_buf_prev_len = *length;
+	if (length != fs->out_buf_prev_len) {
+		fs->out_buf_prev_len = length;
 		fs->out_buf_timeout = 0;
 
+		*__length = cpu_to_be64(length);
 		return OPAL_SUCCESS;
 	}
 
@@ -667,8 +669,10 @@ static int64_t fsp_console_write_buffer_space(int64_t term_number,
 			secs_to_tb(SER_BUFFER_OUT_TIMEOUT);
 	}
 
-	if (tb_compare(mftb(), fs->out_buf_timeout) != TB_AAFTERB)
+	if (tb_compare(mftb(), fs->out_buf_timeout) != TB_AAFTERB) {
+		*__length = cpu_to_be64(length);
 		return OPAL_SUCCESS;
+	}
 
 	/*
 	 * FSP is still active but not reading console data. Hence
@@ -686,13 +690,13 @@ static int64_t fsp_console_write_buffer_space(int64_t term_number,
 	return OPAL_RESOURCE;
 }
 
-static int64_t fsp_console_read(int64_t term_number, int64_t *length,
+static int64_t fsp_console_read(int64_t term_number, __be64 *__length,
 				uint8_t *buffer)
 {
 	struct fsp_serial *fs;
 	struct fsp_serbuf_hdr *sb;
 	bool pending = false;
-	uint32_t old_nin, n, i, chunk, req = *length;
+	uint32_t old_nin, n, i, chunk, req = be64_to_cpu(*__length);
 	int rc = OPAL_SUCCESS;
 
 	if (term_number < 0 || term_number >= MAX_SERIAL)
@@ -716,7 +720,7 @@ static int64_t fsp_console_read(int64_t term_number, int64_t *length,
 		pending = true;
 		n = req;
 	}
-	*length = n;
+	*__length = cpu_to_be64(n);
 
 	chunk = SER_BUF_DATA_SIZE - sb->next_out;
 	if (chunk > n)
diff --git a/hw/fsp/fsp-rtc.c b/hw/fsp/fsp-rtc.c
index 53838f8..e68836e 100644
--- a/hw/fsp/fsp-rtc.c
+++ b/hw/fsp/fsp-rtc.c
@@ -249,12 +249,13 @@ static int64_t fsp_rtc_send_read_request(void)
 	return OPAL_BUSY_EVENT;
 }
 
-static int64_t fsp_opal_rtc_read(uint32_t *year_month_day,
-				 uint64_t *hour_minute_second_millisecond)
+static int64_t fsp_opal_rtc_read(__be32 *__ymd, __be64 *__hmsm)
 {
 	int64_t rc;
+	uint32_t ymd;
+	uint64_t hmsm;
 
-	if (!year_month_day || !hour_minute_second_millisecond)
+	if (!__ymd || !__hmsm)
 		return OPAL_PARAMETER;
 
 	lock(&rtc_lock);
@@ -267,8 +268,7 @@ static int64_t fsp_opal_rtc_read(uint32_t *year_month_day,
 	/* During R/R of FSP, read cached TOD */
 	if (fsp_in_rr()) {
 		if (rtc_tod_state == RTC_TOD_VALID) {
-			rtc_cache_get_datetime(year_month_day,
-					       hour_minute_second_millisecond);
+			rtc_cache_get_datetime(&ymd, &hmsm);
 			rc = OPAL_SUCCESS;
 		} else {
 			rc = OPAL_INTERNAL_ERROR;
@@ -290,11 +290,9 @@ static int64_t fsp_opal_rtc_read(uint32_t *year_month_day,
                 opal_rtc_eval_events(true);
 
                 if (rtc_tod_state == RTC_TOD_VALID) {
-                        rtc_cache_get_datetime(year_month_day,
-					       hour_minute_second_millisecond);
+                        rtc_cache_get_datetime(&ymd, &hmsm);
                         prlog(PR_TRACE,"FSP-RTC Cached datetime: %x %llx\n",
-                              *year_month_day,
-                              *hour_minute_second_millisecond);
+                              ymd, hmsm);
                         rc = OPAL_SUCCESS;
                 } else {
                         rc = OPAL_INTERNAL_ERROR;
@@ -306,8 +304,7 @@ static int64_t fsp_opal_rtc_read(uint32_t *year_month_day,
 		prlog(PR_TRACE, "RTC read timed out\n");
 
 		if (rtc_tod_state == RTC_TOD_VALID) {
-			rtc_cache_get_datetime(year_month_day,
-					       hour_minute_second_millisecond);
+			rtc_cache_get_datetime(&ymd, &hmsm);
 			rc = OPAL_SUCCESS;
 		} else {
                         rc = OPAL_INTERNAL_ERROR;
@@ -319,6 +316,12 @@ static int64_t fsp_opal_rtc_read(uint32_t *year_month_day,
 	}
 out:
 	unlock(&rtc_lock);
+
+	if (rc == OPAL_SUCCESS) {
+		*__ymd = cpu_to_be32(ymd);
+		*__hmsm = cpu_to_be64(hmsm);
+	}
+
 	return rc;
 }
 
diff --git a/hw/fsp/fsp-sensor.c b/hw/fsp/fsp-sensor.c
index 43c8ce4..74deac7 100644
--- a/hw/fsp/fsp-sensor.c
+++ b/hw/fsp/fsp-sensor.c
@@ -70,7 +70,7 @@ enum spcn_attr {
 /* Parsed sensor attributes, passed through OPAL */
 struct opal_sensor_data {
 	uint64_t	async_token;	/* Asynchronous token */
-	uint64_t	*sensor_data;	/* Kernel pointer to copy data */
+	__be64		*sensor_data;	/* Kernel pointer to copy data */
 	enum spcn_attr	spcn_attr;	/* Modifier attribute */
 	uint16_t	rid;		/* Sensor RID */
 	uint8_t		frc;		/* Sensor resource class */
@@ -243,7 +243,7 @@ static void fsp_sensor_process_data(struct opal_sensor_data *attr)
 		sensor_buf_ptr += spcn_mod_data[attr->mod_index].entry_size;
 	}
 
-	*(attr->sensor_data) = sensor_data;
+	*attr->sensor_data = cpu_to_be64(sensor_data);
 	if (sensor_data == INVALID_DATA)
 		queue_msg_for_delivery(OPAL_PARTIAL, attr);
 	else
@@ -345,7 +345,7 @@ static void fsp_sensor_read_complete(struct fsp_msg *msg)
 	unlock(&sensor_lock);
 	return;
 err:
-	*(attr->sensor_data) = INVALID_DATA;
+	*attr->sensor_data = cpu_to_be64(INVALID_DATA);
 	queue_msg_for_delivery(rc, attr);
 	unlock(&sensor_lock);
 	log_simple_error(&e_info(OPAL_RC_SENSOR_ASYNC_COMPLETE),
@@ -496,7 +496,7 @@ static int64_t parse_sensor_id(uint32_t handler, struct opal_sensor_data *attr)
 
 
 int64_t fsp_opal_read_sensor(uint32_t sensor_hndl, int token,
-		uint64_t *sensor_data)
+				__be64 *sensor_data)
 {
 	struct opal_sensor_data *attr;
 	int64_t rc;
diff --git a/hw/ipmi/ipmi-rtc.c b/hw/ipmi/ipmi-rtc.c
index deb4add..ad98f21 100644
--- a/hw/ipmi/ipmi-rtc.c
+++ b/hw/ipmi/ipmi-rtc.c
@@ -62,12 +62,13 @@ static int64_t ipmi_set_sel_time(uint32_t _tv)
 	return ipmi_queue_msg(msg);
 }
 
-static int64_t ipmi_opal_rtc_read(uint32_t *y_m_d,
-				 uint64_t *h_m_s_m)
+static int64_t ipmi_opal_rtc_read(__be32 *__ymd, __be64 *__hmsm)
 {
 	int ret = 0;
+	uint32_t ymd;
+	uint64_t hmsm;
 
-	if (!y_m_d || !h_m_s_m)
+	if (!__ymd || !__hmsm)
 		return OPAL_PARAMETER;
 
 	switch(time_status) {
@@ -83,7 +84,9 @@ static int64_t ipmi_opal_rtc_read(uint32_t *y_m_d,
 		break;
 
 	case updated:
-		rtc_cache_get_datetime(y_m_d, h_m_s_m);
+		rtc_cache_get_datetime(&ymd, &hmsm);
+		*__ymd = cpu_to_be32(ymd);
+		*__hmsm = cpu_to_be64(hmsm);
 		time_status = idle;
 		ret = OPAL_SUCCESS;
 		break;
diff --git a/hw/lpc-rtc.c b/hw/lpc-rtc.c
index f560c8c..ba15941f 100644
--- a/hw/lpc-rtc.c
+++ b/hw/lpc-rtc.c
@@ -139,14 +139,15 @@ static void lpc_init_hw(void)
 	unlock(&rtc_lock);
 }
 
-static int64_t lpc_opal_rtc_read(uint32_t *y_m_d,
-				 uint64_t *h_m_s_m)
+static int64_t lpc_opal_rtc_read(__be32 *__ymd, __be64 *__hmsm)
 {
 	uint8_t val;
 	int64_t rc = OPAL_SUCCESS;
 	struct tm tm;
+	uint32_t ymd;
+	uint64_t hmsm;
 
-	if (!y_m_d || !h_m_s_m)
+	if (!__ymd || !__hmsm)
 		return OPAL_PARAMETER;
 
 	/* Return busy if updating. This is somewhat racy, but will
@@ -172,7 +173,9 @@ static int64_t lpc_opal_rtc_read(uint32_t *y_m_d,
 		rtc_cache_update(&tm);
 
 		/* Convert to OPAL time */
-		tm_to_datetime(&tm, y_m_d, h_m_s_m);
+		tm_to_datetime(&tm, &ymd, &hmsm);
+		*__ymd = cpu_to_be32(ymd);
+		*__hmsm = cpu_to_be64(hmsm);
 	}
 
 	return rc;
diff --git a/hw/lpc-uart.c b/hw/lpc-uart.c
index feca229..b37e042 100644
--- a/hw/lpc-uart.c
+++ b/hw/lpc-uart.c
@@ -255,10 +255,10 @@ static uint32_t uart_tx_buf_space(void)
 		(out_buf_prod + OUT_BUF_SIZE - out_buf_cons) % OUT_BUF_SIZE;
 }
 
-static int64_t uart_opal_write(int64_t term_number, int64_t *length,
+static int64_t uart_opal_write(int64_t term_number, __be64 *__length,
 			       const uint8_t *buffer)
 {
-	size_t written = 0, len = *length;
+	size_t written = 0, len = be64_to_cpu(*__length);
 
 	if (term_number != 0)
 		return OPAL_PARAMETER;
@@ -277,19 +277,19 @@ static int64_t uart_opal_write(int64_t term_number, int64_t *length,
 
 	unlock(&uart_lock);
 
-	*length = written;
+	*__length = cpu_to_be64(written);
 
 	return OPAL_SUCCESS;
 }
 
 static int64_t uart_opal_write_buffer_space(int64_t term_number,
-					    int64_t *length)
+					    __be64 *__length)
 {
 	if (term_number != 0)
 		return OPAL_PARAMETER;
 
 	lock(&uart_lock);
-	*length = uart_tx_buf_space();
+	*__length = cpu_to_be64(uart_tx_buf_space());
 	unlock(&uart_lock);
 
 	return OPAL_SUCCESS;
@@ -326,10 +326,10 @@ static void uart_adjust_opal_event(void)
 }
 
 /* This is called with the console lock held */
-static int64_t uart_opal_read(int64_t term_number, int64_t *length,
+static int64_t uart_opal_read(int64_t term_number, __be64 *__length,
 			      uint8_t *buffer)
 {
-	size_t req_count = *length, read_cnt = 0;
+	size_t req_count = be64_to_cpu(*__length), read_cnt = 0;
 	uint8_t lsr = 0;
 
 	if (term_number != 0)
@@ -373,7 +373,7 @@ static int64_t uart_opal_read(int64_t term_number, int64_t *length,
 	/* Adjust the OPAL event */
 	uart_adjust_opal_event();
 
-	*length = read_cnt;
+	*__length = cpu_to_be64(read_cnt);
 	return OPAL_SUCCESS;
 }
 
diff --git a/hw/lpc.c b/hw/lpc.c
index ec5146f..abf5497 100644
--- a/hw/lpc.c
+++ b/hw/lpc.c
@@ -673,27 +673,36 @@ int64_t lpc_probe_read(enum OpalLPCAddressType addr_type, uint32_t addr,
  * existing Linux expectations
  */
 static int64_t opal_lpc_read(uint32_t chip_id, enum OpalLPCAddressType addr_type,
-			     uint32_t addr, uint32_t *data, uint32_t sz)
+			     uint32_t addr, __be32 *data, uint32_t sz)
 {
 	struct proc_chip *chip;
 	int64_t rc;
+	uint32_t tmp;
 
 	chip = get_chip(chip_id);
 	if (!chip || !chip->lpc)
 		return OPAL_PARAMETER;
 
-	if (addr_type == OPAL_LPC_FW || sz == 1)
-		return __lpc_read(chip->lpc, addr_type, addr, data, sz, false);
-	*data = 0;
-	while(sz--) {
-		uint32_t byte;
-
-		rc = __lpc_read(chip->lpc, addr_type, addr, &byte, 1, false);
+	if (addr_type == OPAL_LPC_FW) {
+		rc = __lpc_read(chip->lpc, addr_type, addr, &tmp, sz, false);
 		if (rc)
 			return rc;
-		*data = *data | (byte << (8 * sz));
-		addr++;
+
+	} else {
+		tmp = 0;
+		while (sz--) {
+			uint32_t byte;
+
+			rc = __lpc_read(chip->lpc, addr_type, addr, &byte, 1, false);
+			if (rc)
+				return rc;
+			tmp = tmp | (byte << (8 * sz));
+			addr++;
+		}
 	}
+
+	*data = cpu_to_be32(tmp);
+
 	return OPAL_SUCCESS;
 }
 
diff --git a/hw/npu2-opencapi.c b/hw/npu2-opencapi.c
index ed6650f..19589c9 100644
--- a/hw/npu2-opencapi.c
+++ b/hw/npu2-opencapi.c
@@ -2250,10 +2250,12 @@ out:
 }
 
 static int64_t opal_npu_mem_alloc(uint64_t phb_id, uint32_t __unused bdfn,
-				  uint64_t size, uint64_t *bar)
+				  uint64_t size, __be64 *__bar)
 {
 	struct phb *phb = pci_get_phb(phb_id);
 	struct npu2_dev *dev;
+	uint64_t bar;
+	int64_t rc;
 
 
 	if (!phb || phb->phb_type != phb_type_npu_v2_opencapi)
@@ -2263,10 +2265,14 @@ static int64_t opal_npu_mem_alloc(uint64_t phb_id, uint32_t __unused bdfn,
 	if (!dev)
 		return OPAL_PARAMETER;
 
-	if (!opal_addr_valid(bar))
+	if (!opal_addr_valid(__bar))
 		return OPAL_PARAMETER;
 
-	return alloc_mem_bar(dev, size, bar);
+	rc = alloc_mem_bar(dev, size, &bar);
+	if (rc == OPAL_SUCCESS)
+		*__bar = cpu_to_be64(bar);
+
+	return rc;
 }
 opal_call(OPAL_NPU_MEM_ALLOC, opal_npu_mem_alloc, 4);
 
diff --git a/hw/occ-sensor.c b/hw/occ-sensor.c
index 8434c19..da846bd 100644
--- a/hw/occ-sensor.c
+++ b/hw/occ-sensor.c
@@ -241,13 +241,14 @@ static void *select_sensor_buffer(struct occ_sensor_data_header *hb, int id)
 	return buffer;
 }
 
-int occ_sensor_read(u32 handle, u64 *data)
+int occ_sensor_read(u32 handle, __be64 *data)
 {
 	struct occ_sensor_data_header *hb;
 	struct occ_sensor_name *md;
 	u16 id = sensor_get_rid(handle);
 	u8 occ_num = sensor_get_frc(handle);
 	u8 attr = sensor_get_attr(handle);
+	u64 d;
 	void *buff;
 
 	if (occ_num > MAX_OCCS)
@@ -271,15 +272,17 @@ int occ_sensor_read(u32 handle, u64 *data)
 	if (!buff)
 		return OPAL_HARDWARE;
 
-	*data = read_sensor(buff, attr);
-	if (!*data)
+	d = read_sensor(buff, attr);
+	if (!d)
 		return OPAL_SUCCESS;
 
 	md = get_names_block(hb);
 	if (md[id].type == OCC_SENSOR_TYPE_POWER && attr == SENSOR_ACCUMULATOR)
-		scale_energy(&md[id], data);
+		scale_energy(&md[id], &d);
 	else
-		scale_sensor(&md[id], data);
+		scale_sensor(&md[id], &d);
+
+	*data = cpu_to_be64(d);
 
 	return OPAL_SUCCESS;
 }
diff --git a/hw/phb4.c b/hw/phb4.c
index e96466d..85d6a0c 100644
--- a/hw/phb4.c
+++ b/hw/phb4.c
@@ -1571,7 +1571,7 @@ static int64_t phb4_set_option(struct phb *phb, enum OpalPhbOption opt,
 }
 
 static int64_t phb4_get_option(struct phb *phb, enum OpalPhbOption opt,
-			       uint64_t *setting)
+			       __be64 *setting)
 {
 	struct phb4 *p = phb_to_phb4(phb);
 	uint64_t data64;
@@ -1579,10 +1579,10 @@ static int64_t phb4_get_option(struct phb *phb, enum OpalPhbOption opt,
 	data64 = phb4_read_reg(p, PHB_CTRLR);
 	switch (opt) {
 	case OPAL_PHB_OPTION_TVE1_4GB:
-		*setting = (data64 & PPC_BIT(24)) ? 1 : 0;
+		*setting = cpu_to_be64((data64 & PPC_BIT(24)) ? 1 : 0);
 		break;
 	case OPAL_PHB_OPTION_MMIO_EEH_DISABLE:
-		*setting = (data64 & PPC_BIT(14)) ? 1 : 0;
+		*setting = cpu_to_be64((data64 & PPC_BIT(14)) ? 1 : 0);
 		break;
 	default:
 		return OPAL_UNSUPPORTED;
diff --git a/hw/xscom.c b/hw/xscom.c
index 381cf2c..a851695 100644
--- a/hw/xscom.c
+++ b/hw/xscom.c
@@ -638,7 +638,17 @@ int _xscom_read(uint32_t partid, uint64_t pcb_addr, uint64_t *val, bool take_loc
 	return rc;
 }
 
-opal_call(OPAL_XSCOM_READ, xscom_read, 3);
+static int64_t opal_xscom_read(uint32_t partid, uint64_t pcb_addr, __be64 *__val)
+{
+	uint64_t val;
+	int64_t rc;
+
+	rc = xscom_read(partid, pcb_addr, &val);
+	*__val = cpu_to_be64(val);
+
+	return rc;
+}
+opal_call(OPAL_XSCOM_READ, opal_xscom_read, 3);
 
 int _xscom_write(uint32_t partid, uint64_t pcb_addr, uint64_t val, bool take_lock)
 {
@@ -682,7 +692,12 @@ int _xscom_write(uint32_t partid, uint64_t pcb_addr, uint64_t val, bool take_loc
 		unlock(&xscom_lock);
 	return rc;
 }
-opal_call(OPAL_XSCOM_WRITE, xscom_write, 3);
+
+static int64_t opal_xscom_write(uint32_t partid, uint64_t pcb_addr, uint64_t val)
+{
+	return xscom_write(partid, pcb_addr, val);
+}
+opal_call(OPAL_XSCOM_WRITE, opal_xscom_write, 3);
 
 /*
  * Perform a xscom read-modify-write.