Date:   Wed,  2 Nov 2016 22:52:06 -0600
From:   Sudeep Holla <sudeep.holla@....com>
To:     Neil Armstrong <narmstrong@...libre.com>
Cc:     Sudeep Holla <sudeep.holla@....com>,
        Olof Johansson <olof@...om.net>,
        linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-amlogic@...ts.infradead.org
Subject: [PATCH v5 3/8] firmware: arm_scpi: add alternative legacy structures, functions and macros

From: Neil Armstrong <narmstrong@...libre.com>

This patch adds support for the Legacy SCPI protocol that is available
in very early JUNO versions and shipped Amlogic ARMv8 based SoCs. Some
Rockchip SoC are also known to use this version of protocol with
extended vendor commands.

In order to support the legacy SCPI protocol variant, we need to add the
structures and macros definitions that varies against the final SCPI v1.0
specification.

We add the indirection table for legacy commands set so that it can
co-exist with the standard v1.0 command set. It also adds bitmap field
for channel selection since the legacy protocol mandates to send only
selected subset of the commands on the high priority channel.

Signed-off-by: Neil Armstrong <narmstrong@...libre.com>
[sudeep.holla@....com: Updated the changelog]
Signed-off-by: Sudeep Holla <sudeep.holla@....com>
---
 drivers/firmware/arm_scpi.c | 192 +++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 174 insertions(+), 18 deletions(-)

diff --git a/drivers/firmware/arm_scpi.c b/drivers/firmware/arm_scpi.c
index 21542a32ad9f..2982bc7b8c33 100644
--- a/drivers/firmware/arm_scpi.c
+++ b/drivers/firmware/arm_scpi.c
@@ -50,13 +50,20 @@
 #define CMD_TOKEN_ID_MASK	0xff
 #define CMD_DATA_SIZE_SHIFT	16
 #define CMD_DATA_SIZE_MASK	0x1ff
+#define CMD_LEGACY_DATA_SIZE_SHIFT	20
+#define CMD_LEGACY_DATA_SIZE_MASK	0x1ff
 #define PACK_SCPI_CMD(cmd_id, tx_sz)			\
 	((((cmd_id) & CMD_ID_MASK) << CMD_ID_SHIFT) |	\
 	(((tx_sz) & CMD_DATA_SIZE_MASK) << CMD_DATA_SIZE_SHIFT))
 #define ADD_SCPI_TOKEN(cmd, token)			\
 	((cmd) |= (((token) & CMD_TOKEN_ID_MASK) << CMD_TOKEN_ID_SHIFT))
+#define PACK_LEGACY_SCPI_CMD(cmd_id, tx_sz)				\
+	((((cmd_id) & CMD_ID_MASK) << CMD_ID_SHIFT) |			       \
+	(((tx_sz) & CMD_LEGACY_DATA_SIZE_MASK) << CMD_LEGACY_DATA_SIZE_SHIFT))
 
 #define CMD_SIZE(cmd)	(((cmd) >> CMD_DATA_SIZE_SHIFT) & CMD_DATA_SIZE_MASK)
+#define CMD_LEGACY_SIZE(cmd)	(((cmd) >> CMD_LEGACY_DATA_SIZE_SHIFT) & \
+					CMD_LEGACY_DATA_SIZE_MASK)
 #define CMD_UNIQ_MASK	(CMD_TOKEN_ID_MASK << CMD_TOKEN_ID_SHIFT | CMD_ID_MASK)
 #define CMD_XTRACT_UNIQ(cmd)	((cmd) & CMD_UNIQ_MASK)
 
@@ -133,7 +140,62 @@ enum scpi_std_cmd {
 	SCPI_CMD_COUNT
 };
 
-/* List of all commands used by this driver, used as indices */
+/* SCPI Legacy Commands */
+enum legacy_scpi_std_cmd {
+	LEGACY_SCPI_CMD_INVALID			= 0x00,
+	LEGACY_SCPI_CMD_SCPI_READY		= 0x01,
+	LEGACY_SCPI_CMD_SCPI_CAPABILITIES	= 0x02,
+	LEGACY_SCPI_CMD_EVENT			= 0x03,
+	LEGACY_SCPI_CMD_SET_CSS_PWR_STATE	= 0x04,
+	LEGACY_SCPI_CMD_GET_CSS_PWR_STATE	= 0x05,
+	LEGACY_SCPI_CMD_CFG_PWR_STATE_STAT	= 0x06,
+	LEGACY_SCPI_CMD_GET_PWR_STATE_STAT	= 0x07,
+	LEGACY_SCPI_CMD_SYS_PWR_STATE		= 0x08,
+	LEGACY_SCPI_CMD_L2_READY		= 0x09,
+	LEGACY_SCPI_CMD_SET_AP_TIMER		= 0x0a,
+	LEGACY_SCPI_CMD_CANCEL_AP_TIME		= 0x0b,
+	LEGACY_SCPI_CMD_DVFS_CAPABILITIES	= 0x0c,
+	LEGACY_SCPI_CMD_GET_DVFS_INFO		= 0x0d,
+	LEGACY_SCPI_CMD_SET_DVFS		= 0x0e,
+	LEGACY_SCPI_CMD_GET_DVFS		= 0x0f,
+	LEGACY_SCPI_CMD_GET_DVFS_STAT		= 0x10,
+	LEGACY_SCPI_CMD_SET_RTC			= 0x11,
+	LEGACY_SCPI_CMD_GET_RTC			= 0x12,
+	LEGACY_SCPI_CMD_CLOCK_CAPABILITIES	= 0x13,
+	LEGACY_SCPI_CMD_SET_CLOCK_INDEX		= 0x14,
+	LEGACY_SCPI_CMD_SET_CLOCK_VALUE		= 0x15,
+	LEGACY_SCPI_CMD_GET_CLOCK_VALUE		= 0x16,
+	LEGACY_SCPI_CMD_PSU_CAPABILITIES	= 0x17,
+	LEGACY_SCPI_CMD_SET_PSU			= 0x18,
+	LEGACY_SCPI_CMD_GET_PSU			= 0x19,
+	LEGACY_SCPI_CMD_SENSOR_CAPABILITIES	= 0x1a,
+	LEGACY_SCPI_CMD_SENSOR_INFO		= 0x1b,
+	LEGACY_SCPI_CMD_SENSOR_VALUE		= 0x1c,
+	LEGACY_SCPI_CMD_SENSOR_CFG_PERIODIC	= 0x1d,
+	LEGACY_SCPI_CMD_SENSOR_CFG_BOUNDS	= 0x1e,
+	LEGACY_SCPI_CMD_SENSOR_ASYNC_VALUE	= 0x1f,
+	LEGACY_SCPI_CMD_COUNT
+};
+
+/* List all commands that are required to go through the high priority link */
+static int legacy_hpriority_cmds[] = {
+	LEGACY_SCPI_CMD_GET_CSS_PWR_STATE,
+	LEGACY_SCPI_CMD_CFG_PWR_STATE_STAT,
+	LEGACY_SCPI_CMD_GET_PWR_STATE_STAT,
+	LEGACY_SCPI_CMD_SET_DVFS,
+	LEGACY_SCPI_CMD_GET_DVFS,
+	LEGACY_SCPI_CMD_SET_RTC,
+	LEGACY_SCPI_CMD_GET_RTC,
+	LEGACY_SCPI_CMD_SET_CLOCK_INDEX,
+	LEGACY_SCPI_CMD_SET_CLOCK_VALUE,
+	LEGACY_SCPI_CMD_GET_CLOCK_VALUE,
+	LEGACY_SCPI_CMD_SET_PSU,
+	LEGACY_SCPI_CMD_GET_PSU,
+	LEGACY_SCPI_CMD_SENSOR_CFG_PERIODIC,
+	LEGACY_SCPI_CMD_SENSOR_CFG_BOUNDS,
+};
+
+/* List all commands used by this driver, used as indexes */
 enum scpi_drv_cmds {
 	CMD_SCPI_CAPABILITIES = 0,
 	CMD_GET_CLOCK_INFO,
@@ -165,6 +227,21 @@ enum scpi_drv_cmds {
 	SCPI_CMD_GET_DEVICE_PWR_STATE,
 };
 
+static int scpi_legacy_commands[CMD_MAX_COUNT] = {
+	LEGACY_SCPI_CMD_SCPI_CAPABILITIES,
+	-1, /* GET_CLOCK_INFO */
+	LEGACY_SCPI_CMD_GET_CLOCK_VALUE,
+	LEGACY_SCPI_CMD_SET_CLOCK_VALUE,
+	LEGACY_SCPI_CMD_GET_DVFS,
+	LEGACY_SCPI_CMD_SET_DVFS,
+	LEGACY_SCPI_CMD_GET_DVFS_INFO,
+	LEGACY_SCPI_CMD_SENSOR_CAPABILITIES,
+	LEGACY_SCPI_CMD_SENSOR_INFO,
+	LEGACY_SCPI_CMD_SENSOR_VALUE,
+	-1, /* SET_DEVICE_PWR_STATE */
+	-1, /* GET_DEVICE_PWR_STATE */
+};
+
 struct scpi_xfer {
 	u32 slot; /* has to be first element */
 	u32 cmd;
@@ -193,8 +270,10 @@ struct scpi_chan {
 struct scpi_drvinfo {
 	u32 protocol_version;
 	u32 firmware_version;
+	bool is_legacy;
 	int num_chans;
 	int *commands;
+	DECLARE_BITMAP(cmd_priority, LEGACY_SCPI_CMD_COUNT);
 	atomic_t next_chan;
 	struct scpi_ops *scpi_ops;
 	struct scpi_chan *channels;
@@ -211,6 +290,11 @@ struct scpi_shared_mem {
 	u8 payload[0];
 } __packed;
 
+struct legacy_scpi_shared_mem {
+	__le32 status;
+	u8 payload[0];
+} __packed;
+
 struct scp_capabilities {
 	__le32 protocol_version;
 	__le32 event_version;
@@ -236,6 +320,12 @@ struct clk_set_value {
 	__le32 rate;
 } __packed;
 
+struct legacy_clk_set_value {
+	__le32 rate;
+	__le16 id;
+	__le16 reserved;
+} __packed;
+
 struct dvfs_info {
 	__le32 header;
 	struct {
@@ -307,19 +397,43 @@ static void scpi_process_cmd(struct scpi_chan *ch, u32 cmd)
 		return;
 	}
 
-	list_for_each_entry(t, &ch->rx_pending, node)
-		if (CMD_XTRACT_UNIQ(t->cmd) == CMD_XTRACT_UNIQ(cmd)) {
-			list_del(&t->node);
-			match = t;
-			break;
-		}
+	/* Command type is not replied by the SCP Firmware in legacy Mode
+	 * We should consider that command is the head of pending RX commands
+	 * if the list is not empty. In TX only mode, the list would be empty.
+	 */
+	if (scpi_info->is_legacy) {
+		match = list_first_entry(&ch->rx_pending, struct scpi_xfer,
+					 node);
+		list_del(&match->node);
+	} else {
+		list_for_each_entry(t, &ch->rx_pending, node)
+			if (CMD_XTRACT_UNIQ(t->cmd) == CMD_XTRACT_UNIQ(cmd)) {
+				list_del(&t->node);
+				match = t;
+				break;
+			}
+	}
 	/* check if wait_for_completion is in progress or timed-out */
 	if (match && !completion_done(&match->done)) {
-		struct scpi_shared_mem *mem = ch->rx_payload;
-		unsigned int len = min(match->rx_len, CMD_SIZE(cmd));
+		unsigned int len;
+
+		if (scpi_info->is_legacy) {
+			struct legacy_scpi_shared_mem *mem = ch->rx_payload;
+
+			/* RX Length is not replied by the legacy Firmware */
+			len = match->rx_len;
+
+			match->status = le32_to_cpu(mem->status);
+			memcpy_fromio(match->rx_buf, mem->payload, len);
+		} else {
+			struct scpi_shared_mem *mem = ch->rx_payload;
+
+			len = min(match->rx_len, CMD_SIZE(cmd));
+
+			match->status = le32_to_cpu(mem->status);
+			memcpy_fromio(match->rx_buf, mem->payload, len);
+		}
 
-		match->status = le32_to_cpu(mem->status);
-		memcpy_fromio(match->rx_buf, mem->payload, len);
 		if (match->rx_len > len)
 			memset(match->rx_buf + len, 0, match->rx_len - len);
 		complete(&match->done);
@@ -331,7 +445,10 @@ 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 *mem = ch->rx_payload;
-	u32 cmd = le32_to_cpu(mem->command);
+	u32 cmd = 0;
+
+	if (!scpi_info->is_legacy)
+		cmd = le32_to_cpu(mem->command);
 
 	scpi_process_cmd(ch, cmd);
 }
@@ -343,8 +460,13 @@ static void scpi_tx_prepare(struct mbox_client *c, void *msg)
 	struct scpi_chan *ch = container_of(c, struct scpi_chan, cl);
 	struct scpi_shared_mem *mem = (struct scpi_shared_mem *)ch->tx_payload;
 
-	if (t->tx_buf)
-		memcpy_toio(mem->payload, t->tx_buf, t->tx_len);
+	if (t->tx_buf) {
+		if (scpi_info->is_legacy)
+			memcpy_toio(ch->tx_payload, t->tx_buf, t->tx_len);
+		else
+			memcpy_toio(mem->payload, t->tx_buf, t->tx_len);
+	}
+
 	if (t->rx_buf) {
 		if (!(++ch->token))
 			++ch->token;
@@ -353,7 +475,9 @@ static void scpi_tx_prepare(struct mbox_client *c, void *msg)
 		list_add_tail(&t->node, &ch->rx_pending);
 		spin_unlock_irqrestore(&ch->rx_lock, flags);
 	}
-	mem->command = cpu_to_le32(t->cmd);
+
+	if (!scpi_info->is_legacy)
+		mem->command = cpu_to_le32(t->cmd);
 }
 
 static struct scpi_xfer *get_scpi_xfer(struct scpi_chan *ch)
@@ -392,15 +516,24 @@ static int scpi_send_message(u8 idx, void *tx_buf, unsigned int tx_len,
 
 	cmd = scpi_info->commands[idx];
 
-	chan = atomic_inc_return(&scpi_info->next_chan) % scpi_info->num_chans;
+	if (scpi_info->is_legacy)
+		chan = test_bit(cmd, scpi_info->cmd_priority) ? 1 : 0;
+	else
+		chan = atomic_inc_return(&scpi_info->next_chan) %
+			scpi_info->num_chans;
 	scpi_chan = scpi_info->channels + chan;
 
 	msg = get_scpi_xfer(scpi_chan);
 	if (!msg)
 		return -ENOMEM;
 
-	msg->slot = BIT(SCPI_SLOT);
-	msg->cmd = PACK_SCPI_CMD(cmd, tx_len);
+	if (scpi_info->is_legacy) {
+		msg->cmd = PACK_LEGACY_SCPI_CMD(cmd, tx_len);
+		msg->slot = msg->cmd;
+	} else {
+		msg->slot = BIT(SCPI_SLOT);
+		msg->cmd = PACK_SCPI_CMD(cmd, tx_len);
+	}
 	msg->tx_buf = tx_buf;
 	msg->tx_len = tx_len;
 	msg->rx_buf = rx_buf;
@@ -470,6 +603,18 @@ static int scpi_clk_set_val(u16 clk_id, unsigned long rate)
 				 &stat, sizeof(stat));
 }
 
+static int legacy_scpi_clk_set_val(u16 clk_id, unsigned long rate)
+{
+	int stat;
+	struct legacy_clk_set_value clk = {
+		.id = cpu_to_le16(clk_id),
+		.rate = cpu_to_le32(rate)
+	};
+
+	return scpi_send_message(CMD_SET_CLOCK_VALUE, &clk, sizeof(clk),
+				 &stat, sizeof(stat));
+}
+
 static int scpi_dvfs_get_idx(u8 domain)
 {
 	int ret;
@@ -800,6 +945,17 @@ static int scpi_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, scpi_info);
 
+	if (scpi_info->is_legacy) {
+		/* Replace with legacy variants */
+		scpi_ops.clk_set_val = legacy_scpi_clk_set_val;
+		scpi_info->commands = scpi_legacy_commands;
+
+		/* Fill priority bitmap */
+		for (idx = 0; idx < ARRAY_SIZE(legacy_hpriority_cmds); idx++)
+			set_bit(legacy_hpriority_cmds[idx],
+				scpi_info->cmd_priority);
+	}
+
 	ret = scpi_init_versions(scpi_info);
 	if (ret) {
 		dev_err(dev, "incorrect or no SCP firmware found\n");
-- 
1.9.1

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