[PATCH v4 5/7] soc: aspeed: add host-side PCIe BMC device driver

[Grégoire Layet]

Add support for VUART over PCIe between BMC and host.
Add the host side driver.
Support only the AST2600.

Taken from ASPEED 6.18 Kernel SDK and trimmed down.

The host can't detect the VUART addresses, so force them to
0x3f8 and 0x2f8, as in the initial ASPEED driver.

Change the MSI vector index of VUART2 from 15 to 17.
The index 15 used in the initial driver was not working.

Data path in both direction is tested on both VUART.

This module is added in soc/aspeed as it's very soc specific.
This is not added as a PCI 8250 UART device as this host module can
be expanded upon for IPMI over KCS. It can also be used in the
future for custom BMC<->host communication with shared memory and doorbell.

This host module should be the entry point for setting up all features
related to an AST2600 present on the PCI bus.

Signed-off-by: Jacky Chou <jacky_chou@xxxxxxxxxxxxxx>
Signed-off-by: aspeedyh <yh_chung@xxxxxxxxxxxxxx>
Signed-off-by: Grégoire Layet <gregoire.layet@xxxxxxxxxxxxx>
---
 drivers/soc/aspeed/Kconfig               |  15 ++
 drivers/soc/aspeed/Makefile              |   1 +
 drivers/soc/aspeed/aspeed-host-bmc-dev.c | 174 +++++++++++++++++++++++
 3 files changed, 190 insertions(+)
 create mode 100644 drivers/soc/aspeed/aspeed-host-bmc-dev.c

diff --git a/drivers/soc/aspeed/Kconfig b/drivers/soc/aspeed/Kconfig
index f579ee0b5afa..147a9033bdc4 100644
--- a/drivers/soc/aspeed/Kconfig
+++ b/drivers/soc/aspeed/Kconfig
@@ -55,3 +55,18 @@ config ASPEED_SOCINFO
 endmenu
 
 endif
+
+menu "ASPEED host-side drivers"
+	depends on PCI
+
+config ASPEED_HOST_BMC_DEV
+	tristate "ASPEED host-side BMC PCIe device"
+	depends on SERIAL_8250
+	help
+	  Host-side driver for the ASPEED AST2600 BMC PCIe device found on
+	  BMC expansion cards. Exposes two 8250-compatible VUART
+	  ports.
+
+	  If unsure, say N. Choose M to build aspeed-host-bmc-dev.
+
+endmenu
diff --git a/drivers/soc/aspeed/Makefile b/drivers/soc/aspeed/Makefile
index b35d74592964..c515e163eab7 100644
--- a/drivers/soc/aspeed/Makefile
+++ b/drivers/soc/aspeed/Makefile
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_ASPEED_HOST_BMC_DEV)	+= aspeed-host-bmc-dev.o
 obj-$(CONFIG_ASPEED_LPC_CTRL)		+= aspeed-lpc-ctrl.o
 obj-$(CONFIG_ASPEED_LPC_SNOOP)		+= aspeed-lpc-snoop.o
 obj-$(CONFIG_ASPEED_UART_ROUTING)	+= aspeed-uart-routing.o
diff --git a/drivers/soc/aspeed/aspeed-host-bmc-dev.c b/drivers/soc/aspeed/aspeed-host-bmc-dev.c
new file mode 100644
index 000000000000..e586d0505577
--- /dev/null
+++ b/drivers/soc/aspeed/aspeed-host-bmc-dev.c
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// Copyright (C) ASPEED Technology Inc.
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/pci.h>
+#include <linux/serial_core.h>
+#include <linux/serial_8250.h>
+
+#define BMC_MULTI_MSI	32
+#define PCI_BMC_DEVICE_ID 0x2402
+
+#define DRIVER_NAME "aspeed-host-bmc-dev"
+
+enum aspeed_platform_id {
+	ASPEED,
+};
+
+static const int vuart_msi_index[2] = { 16, 17 };
+static const int vuart_port_addr[2] = {0x3f8, 0x2f8};
+
+struct aspeed_pci_bmc_dev {
+	unsigned long message_bar_base;
+
+	struct uart_8250_port uart[2];
+	int uart_line[2];
+};
+
+static int aspeed_pci_bmc_device_setup_vuart(struct pci_dev *pdev, int idx)
+{
+	struct aspeed_pci_bmc_dev *pci_bmc_dev = pci_get_drvdata(pdev);
+	struct device *dev = &pdev->dev;
+	struct uart_8250_port *uart = &pci_bmc_dev->uart[idx];
+	u16 vuart_ioport;
+	int ret;
+
+	/* Assign the line to non-exist device before everything is setup */
+	pci_bmc_dev->uart_line[idx] = -ENOENT;
+
+	vuart_ioport = vuart_port_addr[idx];
+	/* ASPEED BMC device shift addresses by 2 to the left */
+	vuart_ioport = vuart_ioport << 2;
+
+	uart->port.flags = UPF_SKIP_TEST | UPF_BOOT_AUTOCONF | UPF_SHARE_IRQ;
+	uart->port.uartclk = 115200 * 16;
+	uart->port.irq = pci_irq_vector(pdev, vuart_msi_index[idx]);
+	uart->port.dev = dev;
+	uart->port.iotype = UPIO_MEM32;
+	uart->port.iobase = 0;
+	uart->port.mapbase = pci_bmc_dev->message_bar_base + vuart_ioport;
+	uart->port.membase = 0;
+	uart->port.type = PORT_16550A;
+	uart->port.flags |= (UPF_IOREMAP | UPF_FIXED_PORT | UPF_FIXED_TYPE);
+	uart->port.regshift = 2;
+
+	ret = serial8250_register_8250_port(&pci_bmc_dev->uart[idx]);
+	if (ret < 0) {
+		dev_err_probe(dev, ret, "Can't setup PCIe VUART%d\n", idx);
+		return ret;
+	}
+
+	pci_bmc_dev->uart_line[idx] = ret;
+
+	return 0;
+}
+
+static void aspeed_pci_host_bmc_device_release_vuart(struct pci_dev *pdev, int idx)
+{
+	struct aspeed_pci_bmc_dev *pci_bmc_dev = pci_get_drvdata(pdev);
+
+	if (pci_bmc_dev->uart_line[idx] >= 0)
+		serial8250_unregister_port(pci_bmc_dev->uart_line[idx]);
+}
+
+static int aspeed_pci_host_setup(struct pci_dev *pdev)
+{
+	struct aspeed_pci_bmc_dev *pci_bmc_dev = pci_get_drvdata(pdev);
+	int rc = 0;
+
+	pci_bmc_dev->message_bar_base = pci_resource_start(pdev, 1);
+
+	if (pdev->revision == 0x27) {
+		pr_err("AST2700 detected but not supported");
+		return -ENODEV;
+	}
+
+	rc = aspeed_pci_bmc_device_setup_vuart(pdev, 0);
+	if (rc)
+		return rc;
+
+	rc = aspeed_pci_bmc_device_setup_vuart(pdev, 1);
+	if (rc)
+		goto out_free_VUART0;
+
+	return 0;
+
+out_free_VUART0:
+	aspeed_pci_host_bmc_device_release_vuart(pdev, 0);
+
+	return rc;
+}
+
+static int aspeed_pci_host_bmc_device_probe(struct pci_dev *pdev, const struct pci_device_id *ent)
+{
+	struct aspeed_pci_bmc_dev *pci_bmc_dev;
+	int rc = 0;
+
+	pci_bmc_dev = devm_kzalloc(&pdev->dev, sizeof(*pci_bmc_dev), GFP_KERNEL);
+	if (!pci_bmc_dev)
+		return -ENOMEM;
+
+	rc = pci_enable_device(pdev);
+	if (rc) {
+		dev_err(&pdev->dev, "pci_enable_device() returned error %d\n", rc);
+		return rc;
+	}
+
+	pci_set_master(pdev);
+	pci_set_drvdata(pdev, pci_bmc_dev);
+
+	rc = pci_alloc_irq_vectors(pdev, BMC_MULTI_MSI, BMC_MULTI_MSI, PCI_IRQ_INTX | PCI_IRQ_MSI);
+	if (rc < 0) {
+		dev_err(&pdev->dev, "aspeed_pci_setup_irq_resource() returned error %d\n", rc);
+		goto disable_device;
+	}
+
+	/* Setup BMC PCI device */
+	rc = aspeed_pci_host_setup(pdev);
+	if (rc) {
+		dev_err(&pdev->dev, "ASPEED PCIe Host device returned error %d\n", rc);
+		goto free_irq;
+	}
+
+	return 0;
+
+free_irq:
+	pci_free_irq_vectors(pdev);
+disable_device:
+	pci_disable_device(pdev);
+	return rc;
+}
+
+static void aspeed_pci_host_bmc_device_remove(struct pci_dev *pdev)
+{
+	aspeed_pci_host_bmc_device_release_vuart(pdev, 0);
+	aspeed_pci_host_bmc_device_release_vuart(pdev, 1);
+
+	pci_free_irq_vectors(pdev);
+	pci_disable_device(pdev);
+}
+
+static struct pci_device_id aspeed_host_bmc_dev_pci_ids[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_ASPEED, PCI_BMC_DEVICE_ID),
+		.class = 0xFF0000, .class_mask = 0xFFFF00,
+		.driver_data = ASPEED },
+	{ 0 }
+};
+
+MODULE_DEVICE_TABLE(pci, aspeed_host_bmc_dev_pci_ids);
+
+static struct pci_driver aspeed_host_bmc_dev_driver = {
+	.name		= DRIVER_NAME,
+	.id_table	= aspeed_host_bmc_dev_pci_ids,
+	.probe		= aspeed_pci_host_bmc_device_probe,
+	.remove		= aspeed_pci_host_bmc_device_remove,
+};
+
+module_driver(aspeed_host_bmc_dev_driver, pci_register_driver, pci_unregister_driver);
+
+MODULE_AUTHOR("Ryan Chen <ryan_chen@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("ASPEED Host BMC DEVICE Driver");
+MODULE_LICENSE("GPL");
-- 
2.54.0