drm/nouveau/i2c/gk110-: disable hw-initiated dpcd reads

RM does this around transactions, and it seemed to help while debugging
AUXCH issues on GA102.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/nvkm/subdev/i2c/aux.h

@@ -3,6 +3,13 @@
 #define __NVKM_I2C_AUX_H__
 #include "pad.h"
 
+static inline void
+nvkm_i2c_aux_autodpcd(struct nvkm_i2c *i2c, int aux, bool enable)
+{
+	if (i2c->func->aux_autodpcd)
+		i2c->func->aux_autodpcd(i2c, aux, false);
+}
+
 struct nvkm_i2c_aux_func {
 	bool address_only;
 	int  (*xfer)(struct nvkm_i2c_aux *, bool retry, u8 type,

drivers/gpu/drm/nouveau/nvkm/subdev/i2c/auxg94.c

@@ -77,7 +77,8 @@ g94_i2c_aux_xfer(struct nvkm_i2c_aux *obj, bool retry,
 		 u8 type, u32 addr, u8 *data, u8 *size)
 {
 	struct g94_i2c_aux *aux = g94_i2c_aux(obj);
-	struct nvkm_device *device = aux->base.pad->i2c->subdev.device;
+	struct nvkm_i2c *i2c = aux->base.pad->i2c;
+	struct nvkm_device *device = i2c->subdev.device;
 	const u32 base = aux->ch * 0x50;
 	u32 ctrl, stat, timeout, retries = 0;
 	u32 xbuf[4] = {};
@@ -96,6 +97,8 @@ g94_i2c_aux_xfer(struct nvkm_i2c_aux *obj, bool retry,
 		goto out;
 	}
 
+	nvkm_i2c_aux_autodpcd(i2c, aux->ch, false);
+
 	if (!(type & 1)) {
 		memcpy(xbuf, data, *size);
 		for (i = 0; i < 16; i += 4) {
@@ -128,7 +131,7 @@ g94_i2c_aux_xfer(struct nvkm_i2c_aux *obj, bool retry,
 			if (!timeout--) {
 				AUX_ERR(&aux->base, "timeout %08x", ctrl);
 				ret = -EIO;
-				goto out;
+				goto out_err;
 			}
 		} while (ctrl & 0x00010000);
 		ret = 0;
@@ -154,7 +157,8 @@ g94_i2c_aux_xfer(struct nvkm_i2c_aux *obj, bool retry,
 		memcpy(data, xbuf, *size);
 		*size = stat & 0x0000001f;
 	}
-
+out_err:
+	nvkm_i2c_aux_autodpcd(i2c, aux->ch, true);
 out:
 	g94_i2c_aux_fini(aux);
 	return ret < 0 ? ret : (stat & 0x000f0000) >> 16;

drivers/gpu/drm/nouveau/nvkm/subdev/i2c/auxgm200.c

@@ -77,7 +77,8 @@ gm200_i2c_aux_xfer(struct nvkm_i2c_aux *obj, bool retry,
 		   u8 type, u32 addr, u8 *data, u8 *size)
 {
 	struct gm200_i2c_aux *aux = gm200_i2c_aux(obj);
-	struct nvkm_device *device = aux->base.pad->i2c->subdev.device;
+	struct nvkm_i2c *i2c = aux->base.pad->i2c;
+	struct nvkm_device *device = i2c->subdev.device;
 	const u32 base = aux->ch * 0x50;
 	u32 ctrl, stat, timeout, retries = 0;
 	u32 xbuf[4] = {};
@@ -96,6 +97,8 @@ gm200_i2c_aux_xfer(struct nvkm_i2c_aux *obj, bool retry,
 		goto out;
 	}
 
+	nvkm_i2c_aux_autodpcd(i2c, aux->ch, false);
+
 	if (!(type & 1)) {
 		memcpy(xbuf, data, *size);
 		for (i = 0; i < 16; i += 4) {
@@ -128,7 +131,7 @@ gm200_i2c_aux_xfer(struct nvkm_i2c_aux *obj, bool retry,
 			if (!timeout--) {
 				AUX_ERR(&aux->base, "timeout %08x", ctrl);
 				ret = -EIO;
-				goto out;
+				goto out_err;
 			}
 		} while (ctrl & 0x00010000);
 		ret = 0;
@@ -155,6 +158,8 @@ gm200_i2c_aux_xfer(struct nvkm_i2c_aux *obj, bool retry,
 		*size = stat & 0x0000001f;
 	}
 
+out_err:
+	nvkm_i2c_aux_autodpcd(i2c, aux->ch, true);
 out:
 	gm200_i2c_aux_fini(aux);
 	return ret < 0 ? ret : (stat & 0x000f0000) >> 16;

drivers/gpu/drm/nouveau/nvkm/subdev/i2c/gk110.c

@@ -22,6 +22,12 @@
 #include "priv.h"
 #include "pad.h"
 
+static void
+gk110_aux_autodpcd(struct nvkm_i2c *i2c, int aux, bool enable)
+{
+	nvkm_mask(i2c->subdev.device, 0x00e4f8 + (aux * 0x50), 0x00010000, enable << 16);
+}
+
 static const struct nvkm_i2c_func
 gk110_i2c = {
 	.pad_x_new = gf119_i2c_pad_x_new,
@@ -29,6 +35,7 @@ gk110_i2c = {
 	.aux = 4,
 	.aux_stat = gk104_aux_stat,
 	.aux_mask = gk104_aux_mask,
+	.aux_autodpcd = gk110_aux_autodpcd,
 };
 
 int

drivers/gpu/drm/nouveau/nvkm/subdev/i2c/gm200.c

@@ -24,6 +24,12 @@
 #include "priv.h"
 #include "pad.h"
 
+static void
+gm200_aux_autodpcd(struct nvkm_i2c *i2c, int aux, bool enable)
+{
+	nvkm_mask(i2c->subdev.device, 0x00d968 + (aux * 0x50), 0x00010000, enable << 16);
+}
+
 static const struct nvkm_i2c_func
 gm200_i2c = {
 	.pad_x_new = gf119_i2c_pad_x_new,
@@ -31,6 +37,7 @@ gm200_i2c = {
 	.aux = 8,
 	.aux_stat = gk104_aux_stat,
 	.aux_mask = gk104_aux_mask,
+	.aux_autodpcd = gm200_aux_autodpcd,
 };
 
 int

drivers/gpu/drm/nouveau/nvkm/subdev/i2c/pad.h

@@ -1,7 +1,7 @@
 /* SPDX-License-Identifier: MIT */
 #ifndef __NVKM_I2C_PAD_H__
 #define __NVKM_I2C_PAD_H__
-#include <subdev/i2c.h>
+#include "priv.h"
 
 struct nvkm_i2c_pad {
 	const struct nvkm_i2c_pad_func *func;

drivers/gpu/drm/nouveau/nvkm/subdev/i2c/priv.h

@@ -23,6 +23,10 @@ struct nvkm_i2c_func {
 	/* mask on/off interrupt types for a given set of auxch
 	 */
 	void (*aux_mask)(struct nvkm_i2c *, u32, u32, u32);
+
+	/* enable/disable HW-initiated DPCD reads
+	 */
+	void (*aux_autodpcd)(struct nvkm_i2c *, int aux, bool enable);
 };
 
 void g94_aux_stat(struct nvkm_i2c *, u32 *, u32 *, u32 *, u32 *);