clk: qcom: clk-rpmh: Add IPA clock support

The clk-rpmh driver only supports on and off RPMh clock resources. Let's
extend the driver by adding support for clocks that are managed by a
different type of RPMh resource known as Bus Clock Manager(BCM). The BCM
is a configurable shared resource aggregator that scales performance
based on a set of frequency points. The Qualcomm IP Accelerator (IPA)
clock is an example of a resource that is managed by the BCM and this a
requirement from the IPA driver in order to scale its core clock.

Signed-off-by: David Dai <[e-mail]>
Signed-off-by: Stephen Boyd <[e-mail]>

drivers/clk/qcom/clk-rpmh.c

···
 #define CLK_RPMH_ARC_EN_OFFSET		0
 #define CLK_RPMH_VRM_EN_OFFSET		4
 
+#define BCM_TCS_CMD_COMMIT_MASK		0x40000000
+#define BCM_TCS_CMD_VALID_SHIFT		29
+#define BCM_TCS_CMD_VOTE_MASK		0x3fff
+#define BCM_TCS_CMD_VOTE_SHIFT		0
+
+#define BCM_TCS_CMD(valid, vote)				\
+	(BCM_TCS_CMD_COMMIT_MASK |				\
+	((valid) << BCM_TCS_CMD_VALID_SHIFT) |			\
+	((vote & BCM_TCS_CMD_VOTE_MASK)				\
+	<< BCM_TCS_CMD_VOTE_SHIFT))
+
+/**
+ * struct bcm_db - Auxiliary data pertaining to each Bus Clock Manager(BCM)
+ * @unit: divisor used to convert Hz value to an RPMh msg
+ * @width: multiplier used to convert Hz value to an RPMh msg
+ * @vcd: virtual clock domain that this bcm belongs to
+ * @reserved: reserved to pad the struct
+ */
+struct bcm_db {
+	__le32 unit;
+	__le16 width;
+	u8 vcd;
+	u8 reserved;
+};
+
 /**
  * struct clk_rpmh - individual rpmh clock data structure
  * @hw:			handle between common and hardware-specific interfaces
···
  * @aggr_state:		rpmh clock aggregated state
  * @last_sent_aggr_state: rpmh clock last aggr state sent to RPMh
  * @valid_state_mask:	mask to determine the state of the rpmh clock
+ * @unit:		divisor to convert rate to rpmh msg in magnitudes of Khz
  * @dev:		device to which it is attached
  * @peer:		pointer to the clock rpmh sibling
  */
···
 	u32 aggr_state;
 	u32 last_sent_aggr_state;
 	u32 valid_state_mask;
+	u32 unit;
 	struct device *dev;
 	struct clk_rpmh *peer;
 };
···
 				_div)					\
 	__DEFINE_CLK_RPMH(_platform, _name, _name_active, _res_name,	\
 			  CLK_RPMH_VRM_EN_OFFSET, 1, _div)
+
+#define DEFINE_CLK_RPMH_BCM(_platform, _name, _res_name)		\
+	static struct clk_rpmh _platform##_##_name = {			\
+		.res_name = _res_name,					\
+		.valid_state_mask = BIT(RPMH_ACTIVE_ONLY_STATE),	\
+		.div = 1,						\
+		.hw.init = &(struct clk_init_data){			\
+			.ops = &clk_rpmh_bcm_ops,			\
+			.name = #_name,					\
+		},							\
+	}
 
 static inline struct clk_rpmh *to_clk_rpmh(struct clk_hw *_hw)
 {
···
 	.recalc_rate	= clk_rpmh_recalc_rate,
 };
 
+static int clk_rpmh_bcm_send_cmd(struct clk_rpmh *c, bool enable)
+{
+	struct tcs_cmd cmd = { 0 };
+	u32 cmd_state;
+	int ret;
+
+	mutex_lock(&rpmh_clk_lock);
+
+	cmd_state = 0;
+	if (enable) {
+		cmd_state = 1;
+		if (c->aggr_state)
+			cmd_state = c->aggr_state;
+	}
+
+	if (c->last_sent_aggr_state == cmd_state) {
+		mutex_unlock(&rpmh_clk_lock);
+		return 0;
+	}
+
+	cmd.addr = c->res_addr;
+	cmd.data = BCM_TCS_CMD(enable, cmd_state);
+
+	ret = rpmh_write_async(c->dev, RPMH_ACTIVE_ONLY_STATE, &cmd, 1);
+	if (ret) {
+		dev_err(c->dev, "set active state of %s failed: (%d)\n",
+			c->res_name, ret);
+		mutex_unlock(&rpmh_clk_lock);
+		return ret;
+	}
+
+	c->last_sent_aggr_state = cmd_state;
+
+	mutex_unlock(&rpmh_clk_lock);
+
+	return 0;
+}
+
+static int clk_rpmh_bcm_prepare(struct clk_hw *hw)
+{
+	struct clk_rpmh *c = to_clk_rpmh(hw);
+
+	return clk_rpmh_bcm_send_cmd(c, true);
+};
+
+static void clk_rpmh_bcm_unprepare(struct clk_hw *hw)
+{
+	struct clk_rpmh *c = to_clk_rpmh(hw);
+
+	clk_rpmh_bcm_send_cmd(c, false);
+};
+
+static int clk_rpmh_bcm_set_rate(struct clk_hw *hw, unsigned long rate,
+				 unsigned long parent_rate)
+{
+	struct clk_rpmh *c = to_clk_rpmh(hw);
+
+	c->aggr_state = rate / c->unit;
+	/*
+	 * Since any non-zero value sent to hw would result in enabling the
+	 * clock, only send the value if the clock has already been prepared.
+	 */
+	if (clk_hw_is_prepared(hw))
+		clk_rpmh_bcm_send_cmd(c, true);
+
+	return 0;
+};
+
+static long clk_rpmh_round_rate(struct clk_hw *hw, unsigned long rate,
+				unsigned long *parent_rate)
+{
+	return rate;
+}
+
+static unsigned long clk_rpmh_bcm_recalc_rate(struct clk_hw *hw,
+					unsigned long prate)
+{
+	struct clk_rpmh *c = to_clk_rpmh(hw);
+
+	return c->aggr_state * c->unit;
+}
+
+static const struct clk_ops clk_rpmh_bcm_ops = {
+	.prepare	= clk_rpmh_bcm_prepare,
+	.unprepare	= clk_rpmh_bcm_unprepare,
+	.set_rate	= clk_rpmh_bcm_set_rate,
+	.round_rate	= clk_rpmh_round_rate,
+	.recalc_rate	= clk_rpmh_bcm_recalc_rate,
+};
+
 /* Resource name must match resource id present in cmd-db. */
 DEFINE_CLK_RPMH_ARC(sdm845, bi_tcxo, bi_tcxo_ao, "xo.lvl", 0x3, 2);
 DEFINE_CLK_RPMH_VRM(sdm845, ln_bb_clk2, ln_bb_clk2_ao, "lnbclka2", 2);
···
 DEFINE_CLK_RPMH_VRM(sdm845, rf_clk1, rf_clk1_ao, "rfclka1", 1);
 DEFINE_CLK_RPMH_VRM(sdm845, rf_clk2, rf_clk2_ao, "rfclka2", 1);
 DEFINE_CLK_RPMH_VRM(sdm845, rf_clk3, rf_clk3_ao, "rfclka3", 1);
+DEFINE_CLK_RPMH_BCM(sdm845, ipa, "IP0");
 
 static struct clk_hw *sdm845_rpmh_clocks[] = {
 	[RPMH_CXO_CLK]		= &sdm845_bi_tcxo.hw,
···
 	[RPMH_RF_CLK2_A]	= &sdm845_rf_clk2_ao.hw,
 	[RPMH_RF_CLK3]		= &sdm845_rf_clk3.hw,
 	[RPMH_RF_CLK3_A]	= &sdm845_rf_clk3_ao.hw,
+	[RPMH_IPA_CLK]		= &sdm845_ipa.hw,
 };
 
 static const struct clk_rpmh_desc clk_rpmh_sdm845 = {
···
 
 	for (i = 0; i < desc->num_clks; i++) {
 		u32 res_addr;
+		size_t aux_data_len;
+		const struct bcm_db *data;
 
 		rpmh_clk = to_clk_rpmh(hw_clks[i]);
 		res_addr = cmd_db_read_addr(rpmh_clk->res_name);
···
 				rpmh_clk->res_name);
 			return -ENODEV;
 		}
+
+		data = cmd_db_read_aux_data(rpmh_clk->res_name, &aux_data_len);
+		if (IS_ERR(data)) {
+			ret = PTR_ERR(data);
+			dev_err(&pdev->dev,
+				"error reading RPMh aux data for %s (%d)\n",
+				rpmh_clk->res_name, ret);
+			return ret;
+		}
+
+		/* Convert unit from Khz to Hz */
+		if (aux_data_len == sizeof(*data))
+			rpmh_clk->unit = le32_to_cpu(data->unit) * 1000ULL;
+
 		rpmh_clk->res_addr += res_addr;
 		rpmh_clk->dev = &pdev->dev;
 

include/dt-bindings/clock/qcom,rpmh.h

···
 #define RPMH_RF_CLK2_A				9
 #define RPMH_RF_CLK3				10
 #define RPMH_RF_CLK3_A				11
+#define RPMH_IPA_CLK				12
 
 #endif