pmdomain: renesas: rcar-sysc: Add R-Car M3-W power-off delay quirk

R-Car M3-W needs a delay of 1 µs before powering off the A3IR and A3VC
power domains.  Add support for this using a new flag, which indicates
that a power area is subject to this quirk.

Inspired by a patch in the BSP by Dien Pham.
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Link: https://lore.kernel.org/r/ecbc3465c598084c904dd3714e2894463094ed9a.1713348705.git.geert+renesas@glider.beSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>

drivers/pmdomain/renesas/r8a77960-sysc.c

@@ -32,12 +32,14 @@ static const struct rcar_sysc_area r8a77960_areas[] __initconst = {
 	{ "ca53-cpu3",	0x200, 3, R8A7796_PD_CA53_CPU3,	R8A7796_PD_CA53_SCU,
 	  PD_CPU_NOCR },
 	{ "cr7",	0x240, 0, R8A7796_PD_CR7,	R8A7796_PD_ALWAYS_ON },
-	{ "a3vc",	0x380, 0, R8A7796_PD_A3VC,	R8A7796_PD_ALWAYS_ON },
+	{ "a3vc",	0x380, 0, R8A7796_PD_A3VC,	R8A7796_PD_ALWAYS_ON,
+	  PD_OFF_DELAY },
 	{ "a2vc0",	0x3c0, 0, R8A7796_PD_A2VC0,	R8A7796_PD_A3VC },
 	{ "a2vc1",	0x3c0, 1, R8A7796_PD_A2VC1,	R8A7796_PD_A3VC },
 	{ "3dg-a",	0x100, 0, R8A7796_PD_3DG_A,	R8A7796_PD_ALWAYS_ON },
 	{ "3dg-b",	0x100, 1, R8A7796_PD_3DG_B,	R8A7796_PD_3DG_A },
-	{ "a3ir",	0x180, 0, R8A7796_PD_A3IR,	R8A7796_PD_ALWAYS_ON },
+	{ "a3ir",	0x180, 0, R8A7796_PD_A3IR,	R8A7796_PD_ALWAYS_ON,
+	  PD_OFF_DELAY },
 };
 
 

drivers/pmdomain/renesas/rcar-sysc.c

@@ -90,6 +90,10 @@ static int rcar_sysc_pwr_on_off(const struct rcar_sysc_pd *pd, bool on)
 	if (ret)
 		return -EAGAIN;
 
+	/* Power-off delay quirk */
+	if (!on && (pd->flags & PD_OFF_DELAY))
+		udelay(1);
+
 	/* Submit power shutoff or power resume request */
 	iowrite32(BIT(pd->chan_bit), rcar_sysc_base + pd->chan_offs + reg_offs);
 

drivers/pmdomain/renesas/rcar-sysc.h

@@ -16,6 +16,7 @@
 #define PD_CPU		BIT(0)	/* Area contains main CPU core */
 #define PD_SCU		BIT(1)	/* Area contains SCU and L2 cache */
 #define PD_NO_CR	BIT(2)	/* Area lacks PWR{ON,OFF}CR registers */
+#define PD_OFF_DELAY	BIT(3)	/* Area is subject to power-off delay quirk */
 
 #define PD_CPU_CR	PD_CPU		  /* CPU area has CR (R-Car H1) */
 #define PD_CPU_NOCR	PD_CPU | PD_NO_CR /* CPU area lacks CR (R-Car Gen2/3) */