firmware: arm_scpi: Revert updates made during v4.15 merge window

Revert "Merge tag 'scpi-updates-4.15' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into next/drivers"

Paraphrased from email from Kevin Hilman:

Revert ARM SCPI changes since v4.14.

Untested changes caused regressions in SCPI and CPUfreq/DVFS failures
on most Amlogic SoCs.  Changes reverted for v4.15 so they can be better
reviewed and tested.

These ARM SCPI changes caused SCPI regressions resulting in CPUfreq
failures on most Amlogic SoCs (found by kernelci.org.)

Unfortunately, this was not caught in linux-next due to other bugs/panics
on these platforms masking this problem so we've only found it since
we've fixed the other issues.

Since we're already in the -rc cycle, I'd prefer to revert to a known
working state (that of v4.14) rather than finding/reverting a subset,
which would just lead to another untested state.

These changes can then have some time to be better reviewed and tested
and resubmitted for v4.16.

Kevin Hilman has tested this revert on the affected Amlogic SoCs and
verified that we're back to the previous (working) condition.

This reverts commit 6710acf2, reversing
changes made to 4b367f2e.
Reported-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Olof Johansson <olof@lixom.net>

drivers/firmware/arm_scpi.c

@@ -28,7 +28,6 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/bitmap.h>
-#include <linux/bitfield.h>
 #include <linux/device.h>
 #include <linux/err.h>
 #include <linux/export.h>
@@ -73,13 +72,21 @@
 
 #define MAX_DVFS_DOMAINS	8
 #define MAX_DVFS_OPPS		16
-
-#define PROTO_REV_MAJOR_MASK	GENMASK(31, 16)
-#define PROTO_REV_MINOR_MASK	GENMASK(15, 0)
-
-#define FW_REV_MAJOR_MASK	GENMASK(31, 24)
-#define FW_REV_MINOR_MASK	GENMASK(23, 16)
-#define FW_REV_PATCH_MASK	GENMASK(15, 0)
+#define DVFS_LATENCY(hdr)	(le32_to_cpu(hdr) >> 16)
+#define DVFS_OPP_COUNT(hdr)	((le32_to_cpu(hdr) >> 8) & 0xff)
+
+#define PROTOCOL_REV_MINOR_BITS	16
+#define PROTOCOL_REV_MINOR_MASK	((1U << PROTOCOL_REV_MINOR_BITS) - 1)
+#define PROTOCOL_REV_MAJOR(x)	((x) >> PROTOCOL_REV_MINOR_BITS)
+#define PROTOCOL_REV_MINOR(x)	((x) & PROTOCOL_REV_MINOR_MASK)
+
+#define FW_REV_MAJOR_BITS	24
+#define FW_REV_MINOR_BITS	16
+#define FW_REV_PATCH_MASK	((1U << FW_REV_MINOR_BITS) - 1)
+#define FW_REV_MINOR_MASK	((1U << FW_REV_MAJOR_BITS) - 1)
+#define FW_REV_MAJOR(x)		((x) >> FW_REV_MAJOR_BITS)
+#define FW_REV_MINOR(x)		(((x) & FW_REV_MINOR_MASK) >> FW_REV_MINOR_BITS)
+#define FW_REV_PATCH(x)		((x) & FW_REV_PATCH_MASK)
 
 #define MAX_RX_TIMEOUT		(msecs_to_jiffies(30))
 
@@ -304,6 +311,10 @@ struct clk_get_info {
 	u8 name[20];
 } __packed;
 
+struct clk_get_value {
+	__le32 rate;
+} __packed;
+
 struct clk_set_value {
 	__le16 id;
 	__le16 reserved;
@@ -317,9 +328,7 @@ struct legacy_clk_set_value {
 } __packed;
 
 struct dvfs_info {
-	u8 domain;
-	u8 opp_count;
-	__le16 latency;
+	__le32 header;
 	struct {
 		__le32 freq;
 		__le32 m_volt;
@@ -342,6 +351,11 @@ struct _scpi_sensor_info {
 	char name[20];
 };
 
+struct sensor_value {
+	__le32 lo_val;
+	__le32 hi_val;
+} __packed;
+
 struct dev_pstate_set {
 	__le16 dev_id;
 	u8 pstate;
@@ -405,20 +419,19 @@ static void scpi_process_cmd(struct scpi_chan *ch, u32 cmd)
 		unsigned int len;
 
 		if (scpi_info->is_legacy) {
-			struct legacy_scpi_shared_mem __iomem *mem =
-							ch->rx_payload;
+			struct legacy_scpi_shared_mem *mem = ch->rx_payload;
 
 			/* RX Length is not replied by the legacy Firmware */
 			len = match->rx_len;
 
-			match->status = ioread32(&mem->status);
+			match->status = le32_to_cpu(mem->status);
 			memcpy_fromio(match->rx_buf, mem->payload, len);
 		} else {
-			struct scpi_shared_mem __iomem *mem = ch->rx_payload;
+			struct scpi_shared_mem *mem = ch->rx_payload;
 
 			len = min(match->rx_len, CMD_SIZE(cmd));
 
-			match->status = ioread32(&mem->status);
+			match->status = le32_to_cpu(mem->status);
 			memcpy_fromio(match->rx_buf, mem->payload, len);
 		}
 
@@ -432,11 +445,11 @@ static void scpi_process_cmd(struct scpi_chan *ch, u32 cmd)
 static void scpi_handle_remote_msg(struct mbox_client *c, void *msg)
 {
 	struct scpi_chan *ch = container_of(c, struct scpi_chan, cl);
-	struct scpi_shared_mem __iomem *mem = ch->rx_payload;
+	struct scpi_shared_mem *mem = ch->rx_payload;
 	u32 cmd = 0;
 
 	if (!scpi_info->is_legacy)
-		cmd = ioread32(&mem->command);
+		cmd = le32_to_cpu(mem->command);
 
 	scpi_process_cmd(ch, cmd);
 }
@@ -446,7 +459,7 @@ static void scpi_tx_prepare(struct mbox_client *c, void *msg)
 	unsigned long flags;
 	struct scpi_xfer *t = msg;
 	struct scpi_chan *ch = container_of(c, struct scpi_chan, cl);
-	struct scpi_shared_mem __iomem *mem = ch->tx_payload;
+	struct scpi_shared_mem *mem = (struct scpi_shared_mem *)ch->tx_payload;
 
 	if (t->tx_buf) {
 		if (scpi_info->is_legacy)
@@ -465,7 +478,7 @@ static void scpi_tx_prepare(struct mbox_client *c, void *msg)
 	}
 
 	if (!scpi_info->is_legacy)
-		iowrite32(t->cmd, &mem->command);
+		mem->command = cpu_to_le32(t->cmd);
 }
 
 static struct scpi_xfer *get_scpi_xfer(struct scpi_chan *ch)
@@ -570,13 +583,13 @@ scpi_clk_get_range(u16 clk_id, unsigned long *min, unsigned long *max)
 static unsigned long scpi_clk_get_val(u16 clk_id)
 {
 	int ret;
-	__le32 rate;
+	struct clk_get_value clk;
 	__le16 le_clk_id = cpu_to_le16(clk_id);
 
 	ret = scpi_send_message(CMD_GET_CLOCK_VALUE, &le_clk_id,
-				sizeof(le_clk_id), &rate, sizeof(rate));
+				sizeof(le_clk_id), &clk, sizeof(clk));
 
-	return ret ? ret : le32_to_cpu(rate);
+	return ret ? ret : le32_to_cpu(clk.rate);
 }
 
 static int scpi_clk_set_val(u16 clk_id, unsigned long rate)
@@ -631,35 +644,35 @@ static int opp_cmp_func(const void *opp1, const void *opp2)
 }
 
 static struct scpi_dvfs_info *scpi_dvfs_get_info(u8 domain)
-{
-	if (domain >= MAX_DVFS_DOMAINS)
-		return ERR_PTR(-EINVAL);
-
-	return scpi_info->dvfs[domain] ?: ERR_PTR(-EINVAL);
-}
-
-static int scpi_dvfs_populate_info(struct device *dev, u8 domain)
 {
 	struct scpi_dvfs_info *info;
 	struct scpi_opp *opp;
 	struct dvfs_info buf;
 	int ret, i;
 
+	if (domain >= MAX_DVFS_DOMAINS)
+		return ERR_PTR(-EINVAL);
+
+	if (scpi_info->dvfs[domain])	/* data already populated */
+		return scpi_info->dvfs[domain];
+
 	ret = scpi_send_message(CMD_GET_DVFS_INFO, &domain, sizeof(domain),
 				&buf, sizeof(buf));
 	if (ret)
-		return ret;
+		return ERR_PTR(ret);
 
-	info = devm_kmalloc(dev, sizeof(*info), GFP_KERNEL);
+	info = kmalloc(sizeof(*info), GFP_KERNEL);
 	if (!info)
-		return -ENOMEM;
+		return ERR_PTR(-ENOMEM);
 
-	info->count = buf.opp_count;
-	info->latency = le16_to_cpu(buf.latency) * 1000; /* uS to nS */
+	info->count = DVFS_OPP_COUNT(buf.header);
+	info->latency = DVFS_LATENCY(buf.header) * 1000; /* uS to nS */
 
-	info->opps = devm_kcalloc(dev, info->count, sizeof(*opp), GFP_KERNEL);
-	if (!info->opps)
-		return -ENOMEM;
+	info->opps = kcalloc(info->count, sizeof(*opp), GFP_KERNEL);
+	if (!info->opps) {
+		kfree(info);
+		return ERR_PTR(-ENOMEM);
+	}
 
 	for (i = 0, opp = info->opps; i < info->count; i++, opp++) {
 		opp->freq = le32_to_cpu(buf.opps[i].freq);
@@ -669,15 +682,7 @@ static int scpi_dvfs_populate_info(struct device *dev, u8 domain)
 	sort(info->opps, info->count, sizeof(*opp), opp_cmp_func, NULL);
 
 	scpi_info->dvfs[domain] = info;
-	return 0;
-}
-
-static void scpi_dvfs_populate(struct device *dev)
-{
-	int domain;
-
-	for (domain = 0; domain < MAX_DVFS_DOMAINS; domain++)
-		scpi_dvfs_populate_info(dev, domain);
+	return info;
 }
 
 static int scpi_dev_domain_id(struct device *dev)
@@ -708,6 +713,9 @@ static int scpi_dvfs_get_transition_latency(struct device *dev)
 	if (IS_ERR(info))
 		return PTR_ERR(info);
 
+	if (!info->latency)
+		return 0;
+
 	return info->latency;
 }
 
@@ -768,19 +776,20 @@ static int scpi_sensor_get_info(u16 sensor_id, struct scpi_sensor_info *info)
 static int scpi_sensor_get_value(u16 sensor, u64 *val)
 {
 	__le16 id = cpu_to_le16(sensor);
-	__le64 value;
+	struct sensor_value buf;
 	int ret;
 
 	ret = scpi_send_message(CMD_SENSOR_VALUE, &id, sizeof(id),
-				&value, sizeof(value));
+				&buf, sizeof(buf));
 	if (ret)
 		return ret;
 
 	if (scpi_info->is_legacy)
-		/* only 32-bits supported, upper 32 bits can be junk */
-		*val = le32_to_cpup((__le32 *)&value);
+		/* only 32-bits supported, hi_val can be junk */
+		*val = le32_to_cpu(buf.lo_val);
 	else
-		*val = le64_to_cpu(value);
+		*val = (u64)le32_to_cpu(buf.hi_val) << 32 |
+			le32_to_cpu(buf.lo_val);
 
 	return 0;
 }
@@ -853,19 +862,23 @@ static int scpi_init_versions(struct scpi_drvinfo *info)
 static ssize_t protocol_version_show(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%lu.%lu\n",
-		FIELD_GET(PROTO_REV_MAJOR_MASK, scpi_info->protocol_version),
-		FIELD_GET(PROTO_REV_MINOR_MASK, scpi_info->protocol_version));
+	struct scpi_drvinfo *scpi_info = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d.%d\n",
+		       PROTOCOL_REV_MAJOR(scpi_info->protocol_version),
+		       PROTOCOL_REV_MINOR(scpi_info->protocol_version));
 }
 static DEVICE_ATTR_RO(protocol_version);
 
 static ssize_t firmware_version_show(struct device *dev,
 				     struct device_attribute *attr, char *buf)
 {
-	return sprintf(buf, "%lu.%lu.%lu\n",
-		     FIELD_GET(FW_REV_MAJOR_MASK, scpi_info->firmware_version),
-		     FIELD_GET(FW_REV_MINOR_MASK, scpi_info->firmware_version),
-		     FIELD_GET(FW_REV_PATCH_MASK, scpi_info->firmware_version));
+	struct scpi_drvinfo *scpi_info = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d.%d.%d\n",
+		       FW_REV_MAJOR(scpi_info->firmware_version),
+		       FW_REV_MINOR(scpi_info->firmware_version),
+		       FW_REV_PATCH(scpi_info->firmware_version));
 }
 static DEVICE_ATTR_RO(firmware_version);
 
@@ -876,13 +889,39 @@ static struct attribute *versions_attrs[] = {
 };
 ATTRIBUTE_GROUPS(versions);
 
-static void scpi_free_channels(void *data)
+static void
+scpi_free_channels(struct device *dev, struct scpi_chan *pchan, int count)
 {
-	struct scpi_drvinfo *info = data;
 	int i;
 
-	for (i = 0; i < info->num_chans; i++)
-		mbox_free_channel(info->channels[i].chan);
+	for (i = 0; i < count && pchan->chan; i++, pchan++) {
+		mbox_free_channel(pchan->chan);
+		devm_kfree(dev, pchan->xfers);
+		devm_iounmap(dev, pchan->rx_payload);
+	}
+}
+
+static int scpi_remove(struct platform_device *pdev)
+{
+	int i;
+	struct device *dev = &pdev->dev;
+	struct scpi_drvinfo *info = platform_get_drvdata(pdev);
+
+	scpi_info = NULL; /* stop exporting SCPI ops through get_scpi_ops */
+
+	of_platform_depopulate(dev);
+	sysfs_remove_groups(&dev->kobj, versions_groups);
+	scpi_free_channels(dev, info->channels, info->num_chans);
+	platform_set_drvdata(pdev, NULL);
+
+	for (i = 0; i < MAX_DVFS_DOMAINS && info->dvfs[i]; i++) {
+		kfree(info->dvfs[i]->opps);
+		kfree(info->dvfs[i]);
+	}
+	devm_kfree(dev, info->channels);
+	devm_kfree(dev, info);
+
+	return 0;
 }
 
 #define MAX_SCPI_XFERS		10
@@ -913,6 +952,7 @@ static int scpi_probe(struct platform_device *pdev)
 {
 	int count, idx, ret;
 	struct resource res;
+	struct scpi_chan *scpi_chan;
 	struct device *dev = &pdev->dev;
 	struct device_node *np = dev->of_node;
 
@@ -929,19 +969,13 @@ static int scpi_probe(struct platform_device *pdev)
 		return -ENODEV;
 	}
 
-	scpi_info->channels = devm_kcalloc(dev, count, sizeof(struct scpi_chan),
-					   GFP_KERNEL);
-	if (!scpi_info->channels)
+	scpi_chan = devm_kcalloc(dev, count, sizeof(*scpi_chan), GFP_KERNEL);
+	if (!scpi_chan)
 		return -ENOMEM;
 
-	ret = devm_add_action(dev, scpi_free_channels, scpi_info);
-	if (ret)
-		return ret;
-
-	for (; scpi_info->num_chans < count; scpi_info->num_chans++) {
+	for (idx = 0; idx < count; idx++) {
 		resource_size_t size;
-		int idx = scpi_info->num_chans;
-		struct scpi_chan *pchan = scpi_info->channels + idx;
+		struct scpi_chan *pchan = scpi_chan + idx;
 		struct mbox_client *cl = &pchan->cl;
 		struct device_node *shmem = of_parse_phandle(np, "shmem", idx);
 
@@ -949,14 +983,15 @@ static int scpi_probe(struct platform_device *pdev)
 		of_node_put(shmem);
 		if (ret) {
 			dev_err(dev, "failed to get SCPI payload mem resource\n");
-			return ret;
+			goto err;
 		}
 
 		size = resource_size(&res);
 		pchan->rx_payload = devm_ioremap(dev, res.start, size);
 		if (!pchan->rx_payload) {
 			dev_err(dev, "failed to ioremap SCPI payload\n");
-			return -EADDRNOTAVAIL;
+			ret = -EADDRNOTAVAIL;
+			goto err;
 		}
 		pchan->tx_payload = pchan->rx_payload + (size >> 1);
 
@@ -982,11 +1017,17 @@ static int scpi_probe(struct platform_device *pdev)
 				dev_err(dev, "failed to get channel%d err %d\n",
 					idx, ret);
 		}
+err:
+		scpi_free_channels(dev, scpi_chan, idx);
+		scpi_info = NULL;
 		return ret;
 	}
 
+	scpi_info->channels = scpi_chan;
+	scpi_info->num_chans = count;
 	scpi_info->commands = scpi_std_commands;
-	scpi_info->scpi_ops = &scpi_ops;
+
+	platform_set_drvdata(pdev, scpi_info);
 
 	if (scpi_info->is_legacy) {
 		/* Replace with legacy variants */
@@ -1002,23 +1043,23 @@ static int scpi_probe(struct platform_device *pdev)
 	ret = scpi_init_versions(scpi_info);
 	if (ret) {
 		dev_err(dev, "incorrect or no SCP firmware found\n");
+		scpi_remove(pdev);
 		return ret;
 	}
 
-	scpi_dvfs_populate(dev);
-
-	_dev_info(dev, "SCP Protocol %lu.%lu Firmware %lu.%lu.%lu version\n",
-		  FIELD_GET(PROTO_REV_MAJOR_MASK, scpi_info->protocol_version),
-		  FIELD_GET(PROTO_REV_MINOR_MASK, scpi_info->protocol_version),
-		  FIELD_GET(FW_REV_MAJOR_MASK, scpi_info->firmware_version),
-		  FIELD_GET(FW_REV_MINOR_MASK, scpi_info->firmware_version),
-		  FIELD_GET(FW_REV_PATCH_MASK, scpi_info->firmware_version));
+	_dev_info(dev, "SCP Protocol %d.%d Firmware %d.%d.%d version\n",
+		  PROTOCOL_REV_MAJOR(scpi_info->protocol_version),
+		  PROTOCOL_REV_MINOR(scpi_info->protocol_version),
+		  FW_REV_MAJOR(scpi_info->firmware_version),
+		  FW_REV_MINOR(scpi_info->firmware_version),
+		  FW_REV_PATCH(scpi_info->firmware_version));
+	scpi_info->scpi_ops = &scpi_ops;
 
-	ret = devm_device_add_groups(dev, versions_groups);
+	ret = sysfs_create_groups(&dev->kobj, versions_groups);
 	if (ret)
 		dev_err(dev, "unable to create sysfs version group\n");
 
-	return devm_of_platform_populate(dev);
+	return of_platform_populate(dev->of_node, NULL, NULL, dev);
 }
 
 static const struct of_device_id scpi_of_match[] = {
@@ -1035,6 +1076,7 @@ static struct platform_driver scpi_driver = {
 		.of_match_table = scpi_of_match,
 	},
 	.probe = scpi_probe,
+	.remove = scpi_remove,
 };
 module_platform_driver(scpi_driver);