linux-kernel - [PATCH] clk: zynqmp: Warn user if clock user are more than allowed

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Message-Id: <1573120694-6015-1-git-send-email-rajan.vaja@xilinx.com>
Date:   Thu,  7 Nov 2019 01:58:14 -0800
From:   Rajan Vaja <rajan.vaja@...inx.com>
To:     mturquette@...libre.com, sboyd@...nel.org, michal.simek@...inx.com,
        shubhrajyoti.datta@...inx.com, jolly.shah@...inx.com,
        nava.manne@...inx.com, tejas.patel@...inx.com
Cc:     linux-clk@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org, Rajan Vaja <rajan.vaja@...inx.com>
Subject: [PATCH] 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: Rajan Vaja <rajan.vaja@...inx.com>
Signed-off-by: Michal Simek <michal.simek@...inx.com>
---
 drivers/clk/zynqmp/pll.c             | 9 ++++++---
 drivers/firmware/xilinx/zynqmp.c     | 2 ++
 include/linux/firmware/xlnx-zynqmp.h | 1 +
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/zynqmp/pll.c b/drivers/clk/zynqmp/pll.c
index a541397..2f4ccaa 100644
--- a/drivers/clk/zynqmp/pll.c
+++ b/drivers/clk/zynqmp/pll.c
@@ -188,9 +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)
-			pr_warn_once("%s() set divider failed for %s, ret = %d\n",
-				     __func__, clk_name, ret);
+		if (ret) {
+			if (ret == -EUSERS)
+				WARN(1, "More than allowed devices are using the %s, which is forbidden\n", clk_name);
+			pr_err("%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);
 
diff --git a/drivers/firmware/xilinx/zynqmp.c b/drivers/firmware/xilinx/zynqmp.c
index 75bdfaa..74d9f13 100644
--- a/drivers/firmware/xilinx/zynqmp.c
+++ b/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:
diff --git a/include/linux/firmware/xlnx-zynqmp.h b/include/linux/firmware/xlnx-zynqmp.h
index adb14bc..a3b0a39 100644
--- a/include/linux/firmware/xlnx-zynqmp.h
+++ b/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 {
-- 
2.7.4