soc/intel/common/uart: Drop chip in favor of devicetree ops

It is now possible to hook up device ops directly to devices in
devicetree which removes the need for a fake chip.

This also fixes Hermes booting as the PCI ops were incorrectly hooked up
to a dummy device. The intel uart driver was requesting a resource from
the generic device and died since it does not exist:

    [EMERG]  GENERIC: 0.0 missing resource: 10

This was broken in commit b9165199c3 (mb/prodrive/hermes: Rework UART
devicetree entry).

Change-Id: I3b32d1cc52afaed2a321eea5815f2957fe730f79
Signed-off-by: Arthur Heymans <arthur@aheymans.xyz>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/82940
Reviewed-by: Christian Walter <christian.walter@9elements.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Nico Huber <nico.h@gmx.de>

src/mainboard/prodrive/hermes/devicetree.cb

@@ -170,12 +170,7 @@ chip soc/intel/cannonlake
 		# This device does not have any function on CNP-H, but it needs
 		# to be here so that the resource allocator is aware of UART 2.
 		device ref i2c4 hidden end
-		device ref uart2 hidden # in ACPI mode
-			chip soc/intel/common/block/uart
-				register "devid" = "PCI_DID_INTEL_CNP_H_UART2"
-				device generic 0 hidden end
-			end
-		end
+		device ref uart2 hidden end # in ACPI mode
 		device ref pcie_rp21 on
 			smbios_slot_desc "SlotTypePciExpressGen3X16" "SlotLengthOther" "SLOT1" "SlotDataBusWidth4X"
 			register "PcieRpEnable[20]" = "1"

src/soc/intel/cannonlake/chip.c

@@ -2,6 +2,7 @@
 
 #include <device/device.h>
 #include <device/pci.h>
+#include <device/pci_ids.h>
 #include <fsp/api.h>
 #include <fsp/util.h>
 #include <gpio.h>
@@ -153,10 +154,20 @@ void soc_init_pre_device(void *chip_info)
 	soc_gpio_pm_configuration();
 
 	/* swap enabled PCI ports in device tree if needed */
-	if (CONFIG(SOC_INTEL_CANNONLAKE_PCH_H))
+	if (CONFIG(SOC_INTEL_CANNONLAKE_PCH_H)) {
 		pcie_rp_update_devicetree(pch_h_rp_groups);
-	else
+
+		/*
+		 * Fix up device ID of hidden PCI device in devicetree.
+		 * This is used by soc/intel/common/block/uart.c to generate ACPI
+		 */
+		struct device *uart2 = PCH_DEV_UART2;
+		if (uart2->hidden)
+			uart2->device = PCI_DID_INTEL_CNP_H_UART2;
+
+	} else {
 		pcie_rp_update_devicetree(pch_lp_rp_groups);
+	}
 }
 
 static void cpu_fill_ssdt(const struct device *dev)

src/soc/intel/cannonlake/chipset_pch_h.cb

@@ -92,7 +92,9 @@ chip soc/intel/cannonlake
 		device pci 17.0 alias sata         off	end	# SATA
 		device pci 19.0 alias i2c4         off	end	# I2C #4
 		device pci 19.1 alias i2c5         off	end	# I2C #5
-		device pci 19.2 alias uart2        off	end	# UART #2
+		device pci 19.2 alias uart2        off		# UART #2
+			ops uart_ops
+		end
 		device pci 1a.0 alias emmc         off	end	# eMMC
 		device pci 1b.0 alias pcie_rp17    off	end	# PCI Express Port 17
 		device pci 1b.1 alias pcie_rp18    off	end	# PCI Express Port 18

src/soc/intel/common/block/uart/chip.h

@@ -1,15 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-
-#include <stdint.h>
-/* Indirect include for static.c: */
-#include <device/pci_ids.h>
-
-#ifndef _SOC_INTEL_COMMON_BLOCK_UART_CHIP_H_
-#define _SOC_INTEL_COMMON_BLOCK_UART_CHIP_H_
-
-struct soc_intel_common_block_uart_config {
-	/* The Device ID read from config space at offset[2:4] when not hidden */
-	u16 devid;
-};
-
-#endif /* _SOC_INTEL_COMMON_BLOCK_UART_CHIP_H_ */

src/soc/intel/common/block/uart/uart.c

@@ -14,7 +14,6 @@
 #include <soc/pci_devs.h>
 #include <soc/iomap.h>
 #include <soc/nvs.h>
-#include "chip.h"
 
 #define UART_PCI_ENABLE	(PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER)
 
@@ -430,17 +429,4 @@ static const struct pci_driver pch_uart __pci_driver = {
 	.vendor		= PCI_VID_INTEL,
 	.devices	= pci_device_ids,
 };
-
-static void uart_enable(struct device *dev)
-{
-	struct soc_intel_common_block_uart_config *conf = dev->chip_info;
-	dev->ops = &uart_ops;
-	dev->device = conf ? conf->devid : 0;
-}
-
-struct chip_operations soc_intel_common_block_uart_ops = {
-	.name = "LPSS UART in ACPI mode",
-	.enable_dev = uart_enable
-};
-
 #endif /* ENV_RAMSTAGE */