drm: apple: Move offsets for rt_bandwidth callback to DT

The offsets differ for every DCP instance. Instead of hardcoding offsets
for each SoC family offsets and calculate the instance offset move
everything to the device tree. This helps multi die SoCs since there is
and unexpected offset between both dies.
On multi die SoCs device tree changes were necessary to avoid
translating the PMGR reg via the seconds die "ranges" property.

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

drivers/gpu/drm/apple/dcp-internal.h

@@ -6,6 +6,7 @@
 
 #include <linux/backlight.h>
 #include <linux/device.h>
+#include <linux/ioport.h>
 #include <linux/mutex.h>
 #include <linux/mux/consumer.h>
 #include <linux/phy/phy.h>
@@ -136,6 +137,13 @@ struct apple_dcp {
 	struct resource *disp_registers[MAX_DISP_REGISTERS];
 	unsigned int nr_disp_registers;
 
+	struct resource disp_bw_scratch_res;
+	struct resource disp_bw_doorbell_res;
+	u32 disp_bw_scratch_index;
+	u32 disp_bw_scratch_offset;
+	u32 disp_bw_doorbell_index;
+	u32 disp_bw_doorbell_offset;
+
 	u32 index;
 
 	/* Bitmap of memory descriptors used for mappings made by the DCP */

drivers/gpu/drm/apple/dcp.c

@@ -14,6 +14,7 @@
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/of_address.h>
 #include <linux/of_device.h>
 #include <linux/of_platform.h>
 #include <linux/slab.h>
@@ -476,11 +477,108 @@ static int dcp_create_piodma_iommu_dev(struct apple_dcp *dcp)
 	return ret;
 }
 
+static int dcp_get_bw_scratch_reg(struct apple_dcp *dcp, u32 expected)
+{
+	struct of_phandle_args ph_args;
+	u32 addr_idx, disp_idx, offset;
+	int ret;
+
+	ret = of_parse_phandle_with_args(dcp->dev->of_node, "apple,bw-scratch",
+				   "#apple,bw-scratch-cells", 0, &ph_args);
+	if (ret < 0) {
+		dev_err(dcp->dev, "Failed to read 'apple,bw-scratch': %d\n", ret);
+		return ret;
+	}
+
+	if (ph_args.args_count != 3) {
+		dev_err(dcp->dev, "Unexpected 'apple,bw-scratch' arg count %d\n",
+			ph_args.args_count);
+		ret = -EINVAL;
+		goto err_of_node_put;
+	}
+
+	addr_idx = ph_args.args[0];
+	disp_idx = ph_args.args[1];
+	offset = ph_args.args[2];
+
+	if (disp_idx != expected || disp_idx >= MAX_DISP_REGISTERS) {
+		dev_err(dcp->dev, "Unexpected disp_reg value in 'apple,bw-scratch': %d\n",
+			disp_idx);
+		ret = -EINVAL;
+		goto err_of_node_put;
+	}
+
+	ret = of_address_to_resource(ph_args.np, addr_idx, &dcp->disp_bw_scratch_res);
+	if (ret < 0) {
+		dev_err(dcp->dev, "Failed to get 'apple,bw-scratch' resource %d from %pOF\n",
+			addr_idx, ph_args.np);
+		goto err_of_node_put;
+	}
+	if (offset > resource_size(&dcp->disp_bw_scratch_res) - 4) {
+		ret = -EINVAL;
+		goto err_of_node_put;
+	}
+
+	dcp->disp_registers[disp_idx] = &dcp->disp_bw_scratch_res;
+	dcp->disp_bw_scratch_index = disp_idx;
+	dcp->disp_bw_scratch_offset = offset;
+	ret = 0;
+
+err_of_node_put:
+	of_node_put(ph_args.np);
+	return ret;
+}
+
+static int dcp_get_bw_doorbell_reg(struct apple_dcp *dcp, u32 expected)
+{
+	struct of_phandle_args ph_args;
+	u32 addr_idx, disp_idx;
+	int ret;
+
+	ret = of_parse_phandle_with_args(dcp->dev->of_node, "apple,bw-doorbell",
+				   "#apple,bw-doorbell-cells", 0, &ph_args);
+	if (ret < 0) {
+		dev_err(dcp->dev, "Failed to read 'apple,bw-doorbell': %d\n", ret);
+		return ret;
+	}
+
+	if (ph_args.args_count != 2) {
+		dev_err(dcp->dev, "Unexpected 'apple,bw-doorbell' arg count %d\n",
+			ph_args.args_count);
+		ret = -EINVAL;
+		goto err_of_node_put;
+	}
+
+	addr_idx = ph_args.args[0];
+	disp_idx = ph_args.args[1];
+
+	if (disp_idx != expected || disp_idx >= MAX_DISP_REGISTERS) {
+		dev_err(dcp->dev, "Unexpected disp_reg value in 'apple,bw-doorbell': %d\n",
+			disp_idx);
+		ret = -EINVAL;
+		goto err_of_node_put;
+	}
+
+	ret = of_address_to_resource(ph_args.np, addr_idx, &dcp->disp_bw_doorbell_res);
+	if (ret < 0) {
+		dev_err(dcp->dev, "Failed to get 'apple,bw-doorbell' resource %d from %pOF\n",
+			addr_idx, ph_args.np);
+		goto err_of_node_put;
+	}
+	dcp->disp_bw_doorbell_index = disp_idx;
+	dcp->disp_registers[disp_idx] = &dcp->disp_bw_doorbell_res;
+	ret = 0;
+
+err_of_node_put:
+	of_node_put(ph_args.np);
+	return ret;
+}
+
 static int dcp_get_disp_regs(struct apple_dcp *dcp)
 {
 	struct platform_device *pdev = to_platform_device(dcp->dev);
 	int count = pdev->num_resources - 1;
-	int i;
+	int i, ret;
 
 	if (count <= 0 || count > MAX_DISP_REGISTERS)
 		return -EINVAL;
@@ -490,6 +588,20 @@ static int dcp_get_disp_regs(struct apple_dcp *dcp)
 			platform_get_resource(pdev, IORESOURCE_MEM, 1 + i);
 	}
 
+	/* load pmgr bandwidth scratch resource and offset */
+	ret = dcp_get_bw_scratch_reg(dcp, count);
+	if (ret < 0)
+		return ret;
+	count += 1;
+
+	/* load pmgr bandwidth doorbell resource if present (only on t8103) */
+	if (of_property_present(dcp->dev->of_node, "apple,bw-doorbell")) {
+		ret = dcp_get_bw_doorbell_reg(dcp, count);
+		if (ret < 0)
+			return ret;
+		count += 1;
+	}
+
 	dcp->nr_disp_registers = count;
 	return 0;
 }
@@ -728,6 +840,14 @@ static int dcp_platform_probe(struct platform_device *pdev)
 	if (fw_compat == DCP_FIRMWARE_UNKNOWN)
 		return -ENODEV;
 
+	/* Check for "apple,bw-scratch" to avoid probing appledrm with outdated
+	 * device trees. This prevents replacing simpledrm and ending up without
+	 * display.
+	 */
+	if (!of_property_present(dev->of_node, "apple,bw-scratch"))
+		return dev_err_probe(dev, -ENODEV, "Incompatible devicetree! "
+			"Use devicetree matching this kernel.\n");
+
 	dcp = devm_kzalloc(dev, sizeof(*dcp), GFP_KERNEL);
 	if (!dcp)
 		return -ENOMEM;

drivers/gpu/drm/apple/iomfb_template.c

@@ -33,11 +33,7 @@
 #include "version_utils.h"
 
 /* Register defines used in bandwidth setup structure */
-#define REG_SCRATCH (0x14)
-#define REG_SCRATCH_T600X (0x988)
-#define REG_SCRATCH_T602X (0x1208)
-#define REG_DOORBELL (0x0)
-#define REG_DOORBELL_BIT (2)
+#define REG_DOORBELL_BIT(idx) (2 + (idx))
 
 struct dcp_wait_cookie {
 	struct kref refcount;
@@ -665,34 +661,31 @@ static struct dcp_allocate_bandwidth_resp dcpep_cb_allocate_bandwidth(struct app
 
 static struct dcp_rt_bandwidth dcpep_cb_rt_bandwidth(struct apple_dcp *dcp)
 {
-	if (dcp->disp_registers[5] && dcp->disp_registers[6]) {
-		return (struct dcp_rt_bandwidth){
-			.reg_scratch =
-				dcp->disp_registers[5]->start + REG_SCRATCH,
-			.reg_doorbell =
-				dcp->disp_registers[6]->start + REG_DOORBELL,
-			.doorbell_bit = REG_DOORBELL_BIT,
-
-			.padding[3] = 0x4, // XXX: required by 11.x firmware
-		};
-	} else if (dcp->disp_registers[4]) {
-		u32 offset = REG_SCRATCH_T600X;
-		if (of_device_is_compatible(dcp->dev->of_node, "apple,t6020-dcp"))
-			offset = REG_SCRATCH_T602X;
-
-		return (struct dcp_rt_bandwidth){
-			.reg_scratch = dcp->disp_registers[4]->start +
-				       offset,
-			.reg_doorbell = 0,
-			.doorbell_bit = 0,
-		};
-	} else {
-		return (struct dcp_rt_bandwidth){
+	struct dcp_rt_bandwidth rt_bw = (struct dcp_rt_bandwidth){
 			.reg_scratch = 0,
 			.reg_doorbell = 0,
 			.doorbell_bit = 0,
-		};
+	};
+
+	if (dcp->disp_bw_scratch_index) {
+		u32 offset = dcp->disp_bw_scratch_offset;
+		u32 index = dcp->disp_bw_scratch_index;
+		rt_bw.reg_scratch = dcp->disp_registers[index]->start + offset;
 	}
+
+	if (dcp->disp_bw_doorbell_index) {
+		u32 index = dcp->disp_bw_doorbell_index;
+		rt_bw.reg_doorbell = dcp->disp_registers[index]->start;
+		rt_bw.doorbell_bit = REG_DOORBELL_BIT(dcp->index);
+		/*
+		 * This is most certainly not padding. t8103-dcp crashes without
+		 * setting this immediately during modeset on 12.3 and 13.5
+		 * firmware.
+		 */
+		rt_bw.padding[3] = 0x4;
+	}
+
+	return rt_bw;
 }
 
 static struct dcp_set_frame_sync_props_resp