soc: mediatek: mtk-cmdq: Add cmdq_pkt_poll_addr() function

Add cmdq_pkt_poll_addr function to support CMDQ user making
an instruction for polling a specific address of hardware rigster
to check the value with or without mask.

POLL is a legacy operation in GCE, so it does not support SPR and
CMDQ_CODE_LOGIC. To support polling the register address which doesn't
have the subsys id, CMDQ users need to make an instruction with GPR and
CMDQ_CODE_MASK operation to move the register address to be poll into GPR.
Then users can make an POLL instruction with GPR to poll the register
address assigned in previous instruction.

Signed-off-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240307013458.23550-4-jason-jh.lin@mediatek.com
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

Author: Jason-JH.Lin

drivers/soc/mediatek/mtk-cmdq-helper.c

@@ -12,6 +12,8 @@
 
 #define CMDQ_WRITE_ENABLE_MASK	BIT(0)
 #define CMDQ_POLL_ENABLE_MASK	BIT(0)
+/* dedicate the last GPR_R15 to assign the register address to be poll */
+#define CMDQ_POLL_ADDR_GPR	(15)
 #define CMDQ_EOC_IRQ_EN		BIT(0)
 #define CMDQ_REG_TYPE		1
 #define CMDQ_JUMP_RELATIVE	0
@@ -397,6 +399,53 @@ int cmdq_pkt_poll_mask(struct cmdq_pkt *pkt, u8 subsys,
 }
 EXPORT_SYMBOL(cmdq_pkt_poll_mask);
 
+int cmdq_pkt_poll_addr(struct cmdq_pkt *pkt, dma_addr_t addr, u32 value, u32 mask)
+{
+	struct cmdq_instruction inst = { {0} };
+	u8 use_mask = 0;
+	int ret;
+
+	/*
+	 * Append an MASK instruction to set the mask for following POLL instruction
+	 * which enables use_mask bit.
+	 */
+	if (mask != GENMASK(31, 0)) {
+		inst.op = CMDQ_CODE_MASK;
+		inst.mask = ~mask;
+		ret = cmdq_pkt_append_command(pkt, inst);
+		if (ret < 0)
+			return ret;
+		use_mask = CMDQ_POLL_ENABLE_MASK;
+	}
+
+	/*
+	 * POLL is an legacy operation in GCE and it does not support SPR and CMDQ_CODE_LOGIC,
+	 * so it can not use cmdq_pkt_assign to keep polling register address to SPR.
+	 * If user wants to poll a register address which doesn't have a subsys id,
+	 * user needs to use GPR and CMDQ_CODE_MASK to move polling register address to GPR.
+	 */
+	inst.op = CMDQ_CODE_MASK;
+	inst.dst_t = CMDQ_REG_TYPE;
+	inst.sop = CMDQ_POLL_ADDR_GPR;
+	inst.value = addr;
+	ret = cmdq_pkt_append_command(pkt, inst);
+	if (ret < 0)
+		return ret;
+
+	/* Append POLL instruction to poll the register address assign to GPR previously. */
+	inst.op = CMDQ_CODE_POLL;
+	inst.dst_t = CMDQ_REG_TYPE;
+	inst.sop = CMDQ_POLL_ADDR_GPR;
+	inst.offset = use_mask;
+	inst.value = value;
+	ret = cmdq_pkt_append_command(pkt, inst);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+EXPORT_SYMBOL(cmdq_pkt_poll_addr);
+
 int cmdq_pkt_assign(struct cmdq_pkt *pkt, u16 reg_idx, u32 value)
 {
 	struct cmdq_instruction inst = {};

include/linux/soc/mediatek/mtk-cmdq.h

@@ -270,6 +270,22 @@ int cmdq_pkt_poll_mask(struct cmdq_pkt *pkt, u8 subsys,
  */
 int cmdq_pkt_assign(struct cmdq_pkt *pkt, u16 reg_idx, u32 value);
 
+/**
+ * cmdq_pkt_poll_addr() - Append blocking POLL command to CMDQ packet
+ * @pkt:	the CMDQ packet
+ * @addr:	the hardware register address
+ * @value:	the specified target register value
+ * @mask:	the specified target register mask
+ *
+ * Appends a polling (POLL) command to the CMDQ packet and asks the GCE
+ * to execute an instruction that checks for the specified `value` (with
+ * or without `mask`) to appear in the specified hardware register `addr`.
+ * All GCE threads will be blocked by this instruction.
+ *
+ * Return: 0 for success or negative error code
+ */
+int cmdq_pkt_poll_addr(struct cmdq_pkt *pkt, dma_addr_t addr, u32 value, u32 mask);
+
 /**
  * cmdq_pkt_jump_abs() - Append jump command to the CMDQ packet, ask GCE
  *			 to execute an instruction that change current thread
@@ -421,6 +437,11 @@ static inline int cmdq_pkt_assign(struct cmdq_pkt *pkt, u16 reg_idx, u32 value)
 	return -EINVAL;
 }
 
+static inline int cmdq_pkt_poll_addr(struct cmdq_pkt *pkt, dma_addr_t addr, u32 value, u32 mask)
+{
+	return -EINVAL;
+}
+
 static inline int cmdq_pkt_jump_abs(struct cmdq_pkt *pkt, dma_addr_t addr, u8 shift_pa)
 {
 	return -EINVAL;