zynqmp: pm: Reimplement clock enable EEMI API

Clock enable EEMI API is reimplemented to use system-level clock
and pll EEMI APIs rather than direct MMIO read/write accesses to clock
and pll control registers.
Since linux still uses clock enable API to trigger locking of the PLLs
in the pm_clock_enable() implementation we need to workaround this by
distinguishing two cases: 1) if the given clock ID corresponds to a PLL
output clock ID; or 2) given clock ID is truly an on-chip clock that can
be gated.
For case 1) we'll call pm_api_clock_pll_enable() implemented in
pm_api_clock.h/c. This function checks what is the buffered PLL mode and
calls the system-level PLL set mode EEMI API with the buffered mode value
specified as argument. Long term, if linux driver get fixed to use PLL
EEMI API to control PLLs, this case could be removed from ATF.
For case 2) we'll call the PMU to configure the clock gate. This is done
using system-level clock enable EEMI API.

Signed-off-by: Mirela Simonovic <mirela.simonovic@aggios.com>
Acked-by: Will Wong <WILLW@xilinx.com>
Signed-off-by: Jolly Shah <jollys@xilinx.com>

plat/xilinx/zynqmp/pm_service/pm_api_clock.c

@@ -2526,7 +2526,7 @@ static struct pm_pll pm_plls[] = {
  *
  * @return	Pointer to PLL structure if found, NULL otherwise
  */
-static struct pm_pll *pm_clock_get_pll(enum clock_id clock_id)
+struct pm_pll *pm_clock_get_pll(enum clock_id clock_id)
 {
 	uint32_t i;
 
@@ -2679,32 +2679,24 @@ static enum pm_ret_status pm_api_clk_enable_disable(unsigned int clock_id,
 }
 
 /**
- * pm_api_clock_enable() - Enable the clock for given id
- * @clock_id: Id of the clock to be enabled
+ * pm_clock_pll_enable() - "Enable" the PLL clock (lock the PLL)
+ * @pll: PLL to be locked
  *
- * This function is used by master to enable the clock
- * including peripherals and PLL clocks.
+ * This function is used to map IOCTL/linux-based PLL handling to system-level
+ * EEMI APIs
  *
- * Return: Returns status, either success or error+reason.
+ * Return: Error if the argument is not valid or status as returned by PMU
  */
-enum pm_ret_status pm_api_clock_enable(unsigned int clock_id)
+enum pm_ret_status pm_clock_pll_enable(struct pm_pll *pll)
 {
-	enum pm_ret_status ret = PM_RET_SUCCESS;
-
-	if (!pm_clock_valid(clock_id))
+	if (!pll)
 		return PM_RET_ERROR_ARGS;
 
-	if (pm_clock_type(clock_id) != CLK_TYPE_OUTPUT)
-		return PM_RET_ERROR_NOTSUPPORTED;
-
-	/*
-	 * PLL type clock should not enable explicitly.
-	 * It is done by FSBL on boot-up and by PMUFW whenever required.
-	 */
-	if (!ISPLL(clock_id))
-		ret = pm_api_clk_enable_disable(clock_id, 1);
+	/* Set the PLL mode according to the buffered mode value */
+	if (pll->mode == PLL_FRAC_MODE)
+		return pm_pll_set_mode(pll->nid, PM_PLL_MODE_FRACTIONAL);
 
-	return ret;
+	return pm_pll_set_mode(pll->nid, PM_PLL_MODE_INTEGER);
 }
 
 /**
@@ -3172,3 +3164,20 @@ enum pm_ret_status pm_clock_get_pll_mode(enum clock_id clock_id,
 
 	return PM_RET_SUCCESS;
 }
+
+/**
+ * pm_clock_id_is_valid() -  Check if given clock ID is valid
+ * @clock_id   ID of the clock to be checked
+ *
+ * @return     Returns success if clock_id is valid, otherwise an error
+ */
+enum pm_ret_status pm_clock_id_is_valid(unsigned int clock_id)
+{
+	if (!pm_clock_valid(clock_id))
+		return PM_RET_ERROR_ARGS;
+
+	if (pm_clock_type(clock_id) != CLK_TYPE_OUTPUT)
+		return PM_RET_ERROR_NOTSUPPORTED;
+
+	return PM_RET_SUCCESS;
+}

plat/xilinx/zynqmp/pm_service/pm_api_clock.h

@@ -274,6 +274,8 @@ enum {
 #define	TYPE_DIV2 5U
 #define	TYPE_GATE 6U
 
+struct pm_pll;
+struct pm_pll *pm_clock_get_pll(enum clock_id clock_id);
 
 enum pm_ret_status pm_api_clock_get_name(unsigned int clock_id, char *name);
 enum pm_ret_status pm_api_clock_get_num_clocks(unsigned int *nclocks);
@@ -291,8 +293,9 @@ enum pm_ret_status pm_api_clock_get_attributes(unsigned int clock_id,
 
 enum pm_ret_status pm_clock_get_pll_node_id(enum clock_id clock_id,
 					    enum pm_node_id *node_id);
+enum pm_ret_status pm_clock_id_is_valid(unsigned int clock_id);
 
-enum pm_ret_status pm_api_clock_enable(unsigned int clock_id);
+enum pm_ret_status pm_clock_pll_enable(struct pm_pll *pll);
 enum pm_ret_status pm_api_clock_disable(unsigned int clock_id);
 enum pm_ret_status pm_api_clock_getstate(unsigned int clock_id,
 					 unsigned int *state);

plat/xilinx/zynqmp/pm_service/pm_api_sys.c

@@ -843,6 +843,36 @@ static enum pm_ret_status pm_clock_get_attributes(unsigned int clock_id,
 	return pm_api_clock_get_attributes(clock_id, attr);
 }
 
+/**
+ * pm_clock_gate() - Configure clock gate
+ * @clock_id	Id of the clock to be configured
+ * @enable	Flag 0=disable (gate the clock), !0=enable (activate the clock)
+ *
+ * @return	Error if an argument is not valid or status as returned by the
+ *		PM controller (PMU)
+ */
+static enum pm_ret_status pm_clock_gate(unsigned int clock_id,
+					unsigned char enable)
+{
+	uint32_t payload[PAYLOAD_ARG_CNT];
+	enum pm_ret_status status;
+	enum pm_api_id api_id;
+
+	/* Check if clock ID is valid and return an error if it is not */
+	status = pm_clock_id_is_valid(clock_id);
+	if (status != PM_RET_SUCCESS)
+		return status;
+
+	if (enable)
+		api_id = PM_CLOCK_ENABLE;
+	else
+		api_id = PM_CLOCK_DISABLE;
+
+	/* Send request to the PMU */
+	PM_PACK_PAYLOAD2(payload, api_id, clock_id);
+	return pm_ipi_send_sync(primary_proc, payload, NULL, 0);
+}
+
 /**
  * pm_clock_enable() - Enable the clock for given id
  * @clock_id: Id of the clock to be enabled
@@ -850,12 +880,20 @@ static enum pm_ret_status pm_clock_get_attributes(unsigned int clock_id,
  * This function is used by master to enable the clock
  * including peripherals and PLL clocks.
  *
- * Return: Returns status, either success or error+reason.
+ * @return:	Error if an argument is not valid or status as returned by the
+ *		pm_clock_gate
  */
-
 enum pm_ret_status pm_clock_enable(unsigned int clock_id)
 {
-	return pm_api_clock_enable(clock_id);
+	struct pm_pll *pll;
+
+	/* First try to handle it as a PLL */
+	pll = pm_clock_get_pll(clock_id);
+	if (pll)
+		return pm_clock_pll_enable(pll);
+
+	/* It's an on-chip clock, PMU should configure clock's gate */
+	return pm_clock_gate(clock_id, 1);
 }
 
 /**