clk: zynqmp: Warn user if clock user are more than allowed

Warn user if clock is used by more than allowed devices.
This check is done by firmware and returns respective
error code. Upon receiving error code for excessive user,
warn user for the same.

This change is done to restrict VPLL use count. It is
assumed that VPLL is used by one user only.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Rajan Vaja <rajan.vaja@xilinx.com>
Link: https://lkml.kernel.org/r/1575527759-26452-4-git-send-email-rajan.vaja@xilinx.com
Acked-by: Michal Simek <michal.simek@xilinx.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

drivers/clk/zynqmp/pll.c

@@ -188,10 +188,12 @@ static int zynqmp_pll_set_rate(struct clk_hw *hw, unsigned long rate,
 		frac = (parent_rate * f) / FRAC_DIV;
 
 		ret = eemi_ops->clock_setdivider(clk_id, m);
-		if (ret)
+		if (ret == -EUSERS)
+			WARN(1, "More than allowed devices are using the %s, which is forbidden\n",
+			     clk_name);
+		else if (ret)
 			pr_warn_once("%s() set divider failed for %s, ret = %d\n",
 				     __func__, clk_name, ret);
-
 		eemi_ops->ioctl(0, IOCTL_SET_PLL_FRAC_DATA, clk_id, f, NULL);
 
 		return rate + frac;

drivers/firmware/xilinx/zynqmp.c

@@ -48,6 +48,8 @@ static int zynqmp_pm_ret_code(u32 ret_status)
 		return -EACCES;
 	case XST_PM_ABORT_SUSPEND:
 		return -ECANCELED;
+	case XST_PM_MULT_USER:
+		return -EUSERS;
 	case XST_PM_INTERNAL:
 	case XST_PM_CONFLICT:
 	case XST_PM_INVALID_NODE:

include/linux/firmware/xlnx-zynqmp.h

@@ -89,6 +89,7 @@ enum pm_ret_status {
 	XST_PM_INVALID_NODE,
 	XST_PM_DOUBLE_REQ,
 	XST_PM_ABORT_SUSPEND,
+	XST_PM_MULT_USER = 2008,
 };
 
 enum pm_ioctl_id {