[PATCH] clk: zynqmp: Work around broken DT GPU node

[Marek Vasut]

The ZynqMP DT GPU node clock description is wrong and does not represent
the hardware correctly, it only describes BUS and PP0 clock, while it is
missing PP1 clock. That means PP1 clock can never be enabled when the GPU
should be used, which leads to expected GPU hang even with simple basic
tests like kmscube.

Since Xilinx does use generated DTs on ZynqMP, the current broken DT
implementation has to be supported. Add a workaround for this breakage
into the clock driver, in case of PP0 enablement attempt, enable PP1
as well and vice versa. This way, the GPU does work and does not hang
because one of its pixel pipeline clock are not enabled.

Signed-off-by: Marek Vasut <marex at denx.de>
---
Cc: Michael Turquette <mturquette at baylibre.com>
Cc: Michal Simek <michal.simek at amd.com>
Cc: Stephen Boyd <sboyd at kernel.org>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-clk at vger.kernel.org
---
 drivers/clk/zynqmp/clk-gate-zynqmp.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/zynqmp/clk-gate-zynqmp.c b/drivers/clk/zynqmp/clk-gate-zynqmp.c
index b89e557371984..b013aa33e7abb 100644
--- a/drivers/clk/zynqmp/clk-gate-zynqmp.c
+++ b/drivers/clk/zynqmp/clk-gate-zynqmp.c
@@ -7,6 +7,7 @@
  * Gated clock implementation
  */
 
+#include <dt-bindings/clock/xlnx-zynqmp-clk.h>
 #include <linux/clk-provider.h>
 #include <linux/slab.h>
 #include "clk-zynqmp.h"
@@ -38,7 +39,13 @@ static int zynqmp_clk_gate_enable(struct clk_hw *hw)
 	u32 clk_id = gate->clk_id;
 	int ret;
 
-	ret = zynqmp_pm_clock_enable(clk_id);
+	if (clk_id == GPU_PP0_REF || clk_id == GPU_PP1_REF) {
+		ret = zynqmp_pm_clock_enable(GPU_PP0_REF);
+		if (!ret)
+			ret = zynqmp_pm_clock_enable(GPU_PP1_REF);
+	} else {
+		ret = zynqmp_pm_clock_enable(clk_id);
+	}
 
 	if (ret)
 		pr_debug("%s() clock enable failed for %s (id %d), ret = %d\n",
@@ -58,7 +65,13 @@ static void zynqmp_clk_gate_disable(struct clk_hw *hw)
 	u32 clk_id = gate->clk_id;
 	int ret;
 
-	ret = zynqmp_pm_clock_disable(clk_id);
+	if (clk_id == GPU_PP0_REF || clk_id == GPU_PP1_REF) {
+		ret = zynqmp_pm_clock_disable(GPU_PP1_REF);
+		if (!ret)
+			ret = zynqmp_pm_clock_disable(GPU_PP0_REF);
+	} else {
+		ret = zynqmp_pm_clock_disable(clk_id);
+	}
 
 	if (ret)
 		pr_debug("%s() clock disable failed for %s (id %d), ret = %d\n",
-- 
2.45.2