The Loongson-2K Board Management Controller provides an PCIe interface
to the host to access the feature implemented in the BMC.
The BMC is assembled on a server similar to the server machine with
Loongson-3 CPU. It supports multiple sub-devices like DRM and IPMI.
Co-developed-by: Chong Qiao <qiaochong@loongson.cn>
Signed-off-by: Chong Qiao <qiaochong@loongson.cn>
Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
Acked-by: Corey Minyard <corey@minyard.net>
Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
---
MAINTAINERS | 6 ++
drivers/mfd/Kconfig | 13 +++
drivers/mfd/Makefile | 2 +
drivers/mfd/ls2k-bmc-core.c | 156 ++++++++++++++++++++++++++++++++++++
4 files changed, 177 insertions(+)
create mode 100644 drivers/mfd/ls2k-bmc-core.c
diff --git a/MAINTAINERS b/MAINTAINERS
index 0d053c45f7f9..4eb0f7b69d35 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14199,6 +14199,12 @@ S: Maintained
F: Documentation/devicetree/bindings/thermal/loongson,ls2k-thermal.yaml
F: drivers/thermal/loongson2_thermal.c
+LOONGSON-2K Board Management Controller (BMC) DRIVER
+M: Binbin Zhou <zhoubinbin@loongson.cn>
+M: Chong Qiao <qiaochong@loongson.cn>
+S: Maintained
+F: drivers/mfd/ls2k-bmc-core.c
+
LOONGSON EDAC DRIVER
M: Zhao Qunqin <zhaoqunqin@loongson.cn>
L: linux-edac@vger.kernel.org
diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
index c635790afa75..47cc8ea9d2ef 100644
--- a/drivers/mfd/Kconfig
+++ b/drivers/mfd/Kconfig
@@ -2400,6 +2400,19 @@ config MFD_INTEL_M10_BMC_PMCI
additional drivers must be enabled in order to use the functionality
of the device.
+config MFD_LS2K_BMC_CORE
+ bool "Loongson-2K Board Management Controller Support"
+ depends on PCI && ACPI_GENERIC_GSI
+ select MFD_CORE
+ help
+ Say yes here to add support for the Loongson-2K BMC which is a Board
+ Management Controller connected to the PCIe bus. The device supports
+ multiple sub-devices like display and IPMI. This driver provides common
+ support for accessing the devices.
+
+ The display is enabled by default in the driver, while the IPMI interface
+ is enabled independently through the IPMI_LS2K option in the IPMI section.
+
config MFD_QNAP_MCU
tristate "QNAP microcontroller unit core driver"
depends on SERIAL_DEV_BUS
diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
index ca351cb0ddcc..675b4ec6ef4c 100644
--- a/drivers/mfd/Makefile
+++ b/drivers/mfd/Makefile
@@ -284,6 +284,8 @@ obj-$(CONFIG_MFD_INTEL_M10_BMC_CORE) += intel-m10-bmc-core.o
obj-$(CONFIG_MFD_INTEL_M10_BMC_SPI) += intel-m10-bmc-spi.o
obj-$(CONFIG_MFD_INTEL_M10_BMC_PMCI) += intel-m10-bmc-pmci.o
+obj-$(CONFIG_MFD_LS2K_BMC_CORE) += ls2k-bmc-core.o
+
obj-$(CONFIG_MFD_ATC260X) += atc260x-core.o
obj-$(CONFIG_MFD_ATC260X_I2C) += atc260x-i2c.o
diff --git a/drivers/mfd/ls2k-bmc-core.c b/drivers/mfd/ls2k-bmc-core.c
new file mode 100644
index 000000000000..50d560a4611c
--- /dev/null
+++ b/drivers/mfd/ls2k-bmc-core.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Loongson-2K Board Management Controller (BMC) Core Driver.
+ *
+ * Copyright (C) 2024-2025 Loongson Technology Corporation Limited.
+ *
+ * Authors:
+ * Chong Qiao <qiaochong@loongson.cn>
+ * Binbin Zhou <zhoubinbin@loongson.cn>
+ */
+
+#include <linux/aperture.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/pci_ids.h>
+#include <linux/platform_data/simplefb.h>
+#include <linux/platform_device.h>
+
+/* LS2K BMC resources */
+#define LS2K_DISPLAY_RES_START (SZ_16M + SZ_2M)
+#define LS2K_IPMI_RES_SIZE 0x1C
+#define LS2K_IPMI0_RES_START (SZ_16M + 0xF00000)
+#define LS2K_IPMI1_RES_START (LS2K_IPMI0_RES_START + LS2K_IPMI_RES_SIZE)
+#define LS2K_IPMI2_RES_START (LS2K_IPMI1_RES_START + LS2K_IPMI_RES_SIZE)
+#define LS2K_IPMI3_RES_START (LS2K_IPMI2_RES_START + LS2K_IPMI_RES_SIZE)
+#define LS2K_IPMI4_RES_START (LS2K_IPMI3_RES_START + LS2K_IPMI_RES_SIZE)
+
+static struct resource ls2k_display_resources[] = {
+ DEFINE_RES_MEM_NAMED(LS2K_DISPLAY_RES_START, SZ_4M, "simpledrm-res"),
+};
+
+static struct resource ls2k_ipmi0_resources[] = {
+ DEFINE_RES_MEM_NAMED(LS2K_IPMI0_RES_START, LS2K_IPMI_RES_SIZE, "ipmi0-res"),
+};
+
+static struct resource ls2k_ipmi1_resources[] = {
+ DEFINE_RES_MEM_NAMED(LS2K_IPMI1_RES_START, LS2K_IPMI_RES_SIZE, "ipmi1-res"),
+};
+
+static struct resource ls2k_ipmi2_resources[] = {
+ DEFINE_RES_MEM_NAMED(LS2K_IPMI2_RES_START, LS2K_IPMI_RES_SIZE, "ipmi2-res"),
+};
+
+static struct resource ls2k_ipmi3_resources[] = {
+ DEFINE_RES_MEM_NAMED(LS2K_IPMI3_RES_START, LS2K_IPMI_RES_SIZE, "ipmi3-res"),
+};
+
+static struct resource ls2k_ipmi4_resources[] = {
+ DEFINE_RES_MEM_NAMED(LS2K_IPMI4_RES_START, LS2K_IPMI_RES_SIZE, "ipmi4-res"),
+};
+
+static struct mfd_cell ls2k_bmc_cells[] = {
+ MFD_CELL_RES("simple-framebuffer", ls2k_display_resources),
+ MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi0_resources),
+ MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi1_resources),
+ MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi2_resources),
+ MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi3_resources),
+ MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi4_resources),
+};
+
+/*
+ * Currently the Loongson-2K BMC hardware does not have an I2C interface to adapt to the
+ * resolution. We set the resolution by presetting "video=1280x1024-16@2M" to the BMC memory.
+ */
+static int ls2k_bmc_parse_mode(struct pci_dev *pdev, struct simplefb_platform_data *pd)
+{
+ char *mode;
+ int depth, ret;
+
+ /* The last 16M of PCI BAR0 is used to store the resolution string. */
+ mode = devm_ioremap(&pdev->dev, pci_resource_start(pdev, 0) + SZ_16M, SZ_16M);
+ if (!mode)
+ return -ENOMEM;
+
+ /* The resolution field starts with the flag "video=". */
+ if (!strncmp(mode, "video=", 6))
+ mode = mode + 6;
+
+ ret = kstrtoint(strsep(&mode, "x"), 10, &pd->width);
+ if (ret)
+ return ret;
+
+ ret = kstrtoint(strsep(&mode, "-"), 10, &pd->height);
+ if (ret)
+ return ret;
+
+ ret = kstrtoint(strsep(&mode, "@"), 10, &depth);
+ if (ret)
+ return ret;
+
+ pd->stride = pd->width * depth / 8;
+ pd->format = depth == 32 ? "a8r8g8b8" : "r5g6b5";
+
+ return 0;
+}
+
+static int ls2k_bmc_probe(struct pci_dev *dev, const struct pci_device_id *id)
+{
+ struct simplefb_platform_data pd;
+ resource_size_t base;
+ int ret;
+
+ ret = pci_enable_device(dev);
+ if (ret)
+ return ret;
+
+ ret = ls2k_bmc_parse_mode(dev, &pd);
+ if (ret)
+ goto disable_pci;
+
+ ls2k_bmc_cells[0].platform_data = &pd;
+ ls2k_bmc_cells[0].pdata_size = sizeof(pd);
+ base = dev->resource[0].start + LS2K_DISPLAY_RES_START;
+
+ /* Remove conflicting efifb device */
+ ret = aperture_remove_conflicting_devices(base, SZ_4M, "simple-framebuffer");
+ if (ret) {
+ dev_err(&dev->dev, "Failed to removed firmware framebuffers: %d\n", ret);
+ goto disable_pci;
+ }
+
+ return devm_mfd_add_devices(&dev->dev, PLATFORM_DEVID_AUTO,
+ ls2k_bmc_cells, ARRAY_SIZE(ls2k_bmc_cells),
+ &dev->resource[0], 0, NULL);
+
+disable_pci:
+ pci_disable_device(dev);
+ return ret;
+}
+
+static void ls2k_bmc_remove(struct pci_dev *dev)
+{
+ pci_disable_device(dev);
+}
+
+static struct pci_device_id ls2k_bmc_devices[] = {
+ { PCI_DEVICE(PCI_VENDOR_ID_LOONGSON, 0x1a05) },
+ { }
+};
+MODULE_DEVICE_TABLE(pci, ls2k_bmc_devices);
+
+static struct pci_driver ls2k_bmc_driver = {
+ .name = "ls2k-bmc",
+ .id_table = ls2k_bmc_devices,
+ .probe = ls2k_bmc_probe,
+ .remove = ls2k_bmc_remove,
+};
+module_pci_driver(ls2k_bmc_driver);
+
+MODULE_DESCRIPTION("Loongson-2K Board Management Controller (BMC) Core driver");
+MODULE_AUTHOR("Loongson Technology Corporation Limited");
+MODULE_LICENSE("GPL");
--
2.47.1On Fri, 04 Jul 2025, Binbin Zhou wrote:
> The Loongson-2K Board Management Controller provides an PCIe interface
> to the host to access the feature implemented in the BMC.
>
> The BMC is assembled on a server similar to the server machine with
> Loongson-3 CPU. It supports multiple sub-devices like DRM and IPMI.
>
> Co-developed-by: Chong Qiao <qiaochong@loongson.cn>
> Signed-off-by: Chong Qiao <qiaochong@loongson.cn>
> Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
> Acked-by: Corey Minyard <corey@minyard.net>
> Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
> ---
> MAINTAINERS | 6 ++
> drivers/mfd/Kconfig | 13 +++
> drivers/mfd/Makefile | 2 +
> drivers/mfd/ls2k-bmc-core.c | 156 ++++++++++++++++++++++++++++++++++++
> 4 files changed, 177 insertions(+)
> create mode 100644 drivers/mfd/ls2k-bmc-core.c
>
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 0d053c45f7f9..4eb0f7b69d35 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -14199,6 +14199,12 @@ S: Maintained
> F: Documentation/devicetree/bindings/thermal/loongson,ls2k-thermal.yaml
> F: drivers/thermal/loongson2_thermal.c
>
> +LOONGSON-2K Board Management Controller (BMC) DRIVER
> +M: Binbin Zhou <zhoubinbin@loongson.cn>
> +M: Chong Qiao <qiaochong@loongson.cn>
> +S: Maintained
> +F: drivers/mfd/ls2k-bmc-core.c
> +
> LOONGSON EDAC DRIVER
> M: Zhao Qunqin <zhaoqunqin@loongson.cn>
> L: linux-edac@vger.kernel.org
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index c635790afa75..47cc8ea9d2ef 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -2400,6 +2400,19 @@ config MFD_INTEL_M10_BMC_PMCI
> additional drivers must be enabled in order to use the functionality
> of the device.
>
> +config MFD_LS2K_BMC_CORE
> + bool "Loongson-2K Board Management Controller Support"
> + depends on PCI && ACPI_GENERIC_GSI
> + select MFD_CORE
> + help
> + Say yes here to add support for the Loongson-2K BMC which is a Board
> + Management Controller connected to the PCIe bus. The device supports
> + multiple sub-devices like display and IPMI. This driver provides common
> + support for accessing the devices.
> +
> + The display is enabled by default in the driver, while the IPMI interface
> + is enabled independently through the IPMI_LS2K option in the IPMI section.
> +
> config MFD_QNAP_MCU
> tristate "QNAP microcontroller unit core driver"
> depends on SERIAL_DEV_BUS
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index ca351cb0ddcc..675b4ec6ef4c 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -284,6 +284,8 @@ obj-$(CONFIG_MFD_INTEL_M10_BMC_CORE) += intel-m10-bmc-core.o
> obj-$(CONFIG_MFD_INTEL_M10_BMC_SPI) += intel-m10-bmc-spi.o
> obj-$(CONFIG_MFD_INTEL_M10_BMC_PMCI) += intel-m10-bmc-pmci.o
>
> +obj-$(CONFIG_MFD_LS2K_BMC_CORE) += ls2k-bmc-core.o
> +
> obj-$(CONFIG_MFD_ATC260X) += atc260x-core.o
> obj-$(CONFIG_MFD_ATC260X_I2C) += atc260x-i2c.o
>
> diff --git a/drivers/mfd/ls2k-bmc-core.c b/drivers/mfd/ls2k-bmc-core.c
> new file mode 100644
> index 000000000000..50d560a4611c
> --- /dev/null
> +++ b/drivers/mfd/ls2k-bmc-core.c
> @@ -0,0 +1,156 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Loongson-2K Board Management Controller (BMC) Core Driver.
> + *
> + * Copyright (C) 2024-2025 Loongson Technology Corporation Limited.
> + *
> + * Authors:
> + * Chong Qiao <qiaochong@loongson.cn>
> + * Binbin Zhou <zhoubinbin@loongson.cn>
> + */
> +
> +#include <linux/aperture.h>
> +#include <linux/errno.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/mfd/core.h>
> +#include <linux/module.h>
> +#include <linux/pci.h>
> +#include <linux/pci_ids.h>
> +#include <linux/platform_data/simplefb.h>
> +#include <linux/platform_device.h>
> +
> +/* LS2K BMC resources */
> +#define LS2K_DISPLAY_RES_START (SZ_16M + SZ_2M)
> +#define LS2K_IPMI_RES_SIZE 0x1C
> +#define LS2K_IPMI0_RES_START (SZ_16M + 0xF00000)
> +#define LS2K_IPMI1_RES_START (LS2K_IPMI0_RES_START + LS2K_IPMI_RES_SIZE)
> +#define LS2K_IPMI2_RES_START (LS2K_IPMI1_RES_START + LS2K_IPMI_RES_SIZE)
> +#define LS2K_IPMI3_RES_START (LS2K_IPMI2_RES_START + LS2K_IPMI_RES_SIZE)
> +#define LS2K_IPMI4_RES_START (LS2K_IPMI3_RES_START + LS2K_IPMI_RES_SIZE)
> +
> +static struct resource ls2k_display_resources[] = {
> + DEFINE_RES_MEM_NAMED(LS2K_DISPLAY_RES_START, SZ_4M, "simpledrm-res"),
> +};
> +
> +static struct resource ls2k_ipmi0_resources[] = {
> + DEFINE_RES_MEM_NAMED(LS2K_IPMI0_RES_START, LS2K_IPMI_RES_SIZE, "ipmi0-res"),
> +};
> +
> +static struct resource ls2k_ipmi1_resources[] = {
> + DEFINE_RES_MEM_NAMED(LS2K_IPMI1_RES_START, LS2K_IPMI_RES_SIZE, "ipmi1-res"),
> +};
> +
> +static struct resource ls2k_ipmi2_resources[] = {
> + DEFINE_RES_MEM_NAMED(LS2K_IPMI2_RES_START, LS2K_IPMI_RES_SIZE, "ipmi2-res"),
> +};
> +
> +static struct resource ls2k_ipmi3_resources[] = {
> + DEFINE_RES_MEM_NAMED(LS2K_IPMI3_RES_START, LS2K_IPMI_RES_SIZE, "ipmi3-res"),
> +};
> +
> +static struct resource ls2k_ipmi4_resources[] = {
> + DEFINE_RES_MEM_NAMED(LS2K_IPMI4_RES_START, LS2K_IPMI_RES_SIZE, "ipmi4-res"),
> +};
> +
> +static struct mfd_cell ls2k_bmc_cells[] = {
> + MFD_CELL_RES("simple-framebuffer", ls2k_display_resources),
> + MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi0_resources),
> + MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi1_resources),
> + MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi2_resources),
> + MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi3_resources),
> + MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi4_resources),
> +};
> +
> +/*
> + * Currently the Loongson-2K BMC hardware does not have an I2C interface to adapt to the
> + * resolution. We set the resolution by presetting "video=1280x1024-16@2M" to the BMC memory.
> + */
> +static int ls2k_bmc_parse_mode(struct pci_dev *pdev, struct simplefb_platform_data *pd)
> +{
> + char *mode;
> + int depth, ret;
> +
> + /* The last 16M of PCI BAR0 is used to store the resolution string. */
> + mode = devm_ioremap(&pdev->dev, pci_resource_start(pdev, 0) + SZ_16M, SZ_16M);
> + if (!mode)
> + return -ENOMEM;
> +
> + /* The resolution field starts with the flag "video=". */
> + if (!strncmp(mode, "video=", 6))
> + mode = mode + 6;
> +
> + ret = kstrtoint(strsep(&mode, "x"), 10, &pd->width);
> + if (ret)
> + return ret;
> +
> + ret = kstrtoint(strsep(&mode, "-"), 10, &pd->height);
> + if (ret)
> + return ret;
> +
> + ret = kstrtoint(strsep(&mode, "@"), 10, &depth);
> + if (ret)
> + return ret;
> +
> + pd->stride = pd->width * depth / 8;
> + pd->format = depth == 32 ? "a8r8g8b8" : "r5g6b5";
> +
> + return 0;
> +}
> +
> +static int ls2k_bmc_probe(struct pci_dev *dev, const struct pci_device_id *id)
> +{
> + struct simplefb_platform_data pd;
> + resource_size_t base;
> + int ret;
> +
> + ret = pci_enable_device(dev);
> + if (ret)
> + return ret;
> +
> + ret = ls2k_bmc_parse_mode(dev, &pd);
> + if (ret)
> + goto disable_pci;
> +
> + ls2k_bmc_cells[0].platform_data = &pd;
> + ls2k_bmc_cells[0].pdata_size = sizeof(pd);
This is fragile.
Please identify the elements in ls2k_bmc_cells and use it to index here.
See: `static struct mfd_cell as3711_subdevs`
> + base = dev->resource[0].start + LS2K_DISPLAY_RES_START;
> +
> + /* Remove conflicting efifb device */
> + ret = aperture_remove_conflicting_devices(base, SZ_4M, "simple-framebuffer");
> + if (ret) {
> + dev_err(&dev->dev, "Failed to removed firmware framebuffers: %d\n", ret);
> + goto disable_pci;
> + }
> +
> + return devm_mfd_add_devices(&dev->dev, PLATFORM_DEVID_AUTO,
> + ls2k_bmc_cells, ARRAY_SIZE(ls2k_bmc_cells),
> + &dev->resource[0], 0, NULL);
> +
> +disable_pci:
> + pci_disable_device(dev);
> + return ret;
> +}
> +
> +static void ls2k_bmc_remove(struct pci_dev *dev)
> +{
> + pci_disable_device(dev);
> +}
> +
> +static struct pci_device_id ls2k_bmc_devices[] = {
> + { PCI_DEVICE(PCI_VENDOR_ID_LOONGSON, 0x1a05) },
> + { }
> +};
> +MODULE_DEVICE_TABLE(pci, ls2k_bmc_devices);
> +
> +static struct pci_driver ls2k_bmc_driver = {
> + .name = "ls2k-bmc",
> + .id_table = ls2k_bmc_devices,
> + .probe = ls2k_bmc_probe,
> + .remove = ls2k_bmc_remove,
> +};
> +module_pci_driver(ls2k_bmc_driver);
> +
> +MODULE_DESCRIPTION("Loongson-2K Board Management Controller (BMC) Core driver");
> +MODULE_AUTHOR("Loongson Technology Corporation Limited");
> +MODULE_LICENSE("GPL");
> --
> 2.47.1
>
--
Lee Jones [李琼斯]
Hi Lee:
Thanks for your review.
On Thu, Jul 10, 2025 at 5:56 PM Lee Jones <lee@kernel.org> wrote:
>
> On Fri, 04 Jul 2025, Binbin Zhou wrote:
>
> > The Loongson-2K Board Management Controller provides an PCIe interface
> > to the host to access the feature implemented in the BMC.
> >
> > The BMC is assembled on a server similar to the server machine with
> > Loongson-3 CPU. It supports multiple sub-devices like DRM and IPMI.
> >
> > Co-developed-by: Chong Qiao <qiaochong@loongson.cn>
> > Signed-off-by: Chong Qiao <qiaochong@loongson.cn>
> > Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
> > Acked-by: Corey Minyard <corey@minyard.net>
> > Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
> > ---
> > MAINTAINERS | 6 ++
> > drivers/mfd/Kconfig | 13 +++
> > drivers/mfd/Makefile | 2 +
> > drivers/mfd/ls2k-bmc-core.c | 156 ++++++++++++++++++++++++++++++++++++
> > 4 files changed, 177 insertions(+)
> > create mode 100644 drivers/mfd/ls2k-bmc-core.c
> >
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index 0d053c45f7f9..4eb0f7b69d35 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -14199,6 +14199,12 @@ S: Maintained
> > F: Documentation/devicetree/bindings/thermal/loongson,ls2k-thermal.yaml
> > F: drivers/thermal/loongson2_thermal.c
> >
> > +LOONGSON-2K Board Management Controller (BMC) DRIVER
> > +M: Binbin Zhou <zhoubinbin@loongson.cn>
> > +M: Chong Qiao <qiaochong@loongson.cn>
> > +S: Maintained
> > +F: drivers/mfd/ls2k-bmc-core.c
> > +
> > LOONGSON EDAC DRIVER
> > M: Zhao Qunqin <zhaoqunqin@loongson.cn>
> > L: linux-edac@vger.kernel.org
> > diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> > index c635790afa75..47cc8ea9d2ef 100644
> > --- a/drivers/mfd/Kconfig
> > +++ b/drivers/mfd/Kconfig
> > @@ -2400,6 +2400,19 @@ config MFD_INTEL_M10_BMC_PMCI
> > additional drivers must be enabled in order to use the functionality
> > of the device.
> >
> > +config MFD_LS2K_BMC_CORE
> > + bool "Loongson-2K Board Management Controller Support"
> > + depends on PCI && ACPI_GENERIC_GSI
> > + select MFD_CORE
> > + help
> > + Say yes here to add support for the Loongson-2K BMC which is a Board
> > + Management Controller connected to the PCIe bus. The device supports
> > + multiple sub-devices like display and IPMI. This driver provides common
> > + support for accessing the devices.
> > +
> > + The display is enabled by default in the driver, while the IPMI interface
> > + is enabled independently through the IPMI_LS2K option in the IPMI section.
> > +
> > config MFD_QNAP_MCU
> > tristate "QNAP microcontroller unit core driver"
> > depends on SERIAL_DEV_BUS
> > diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> > index ca351cb0ddcc..675b4ec6ef4c 100644
> > --- a/drivers/mfd/Makefile
> > +++ b/drivers/mfd/Makefile
> > @@ -284,6 +284,8 @@ obj-$(CONFIG_MFD_INTEL_M10_BMC_CORE) += intel-m10-bmc-core.o
> > obj-$(CONFIG_MFD_INTEL_M10_BMC_SPI) += intel-m10-bmc-spi.o
> > obj-$(CONFIG_MFD_INTEL_M10_BMC_PMCI) += intel-m10-bmc-pmci.o
> >
> > +obj-$(CONFIG_MFD_LS2K_BMC_CORE) += ls2k-bmc-core.o
> > +
> > obj-$(CONFIG_MFD_ATC260X) += atc260x-core.o
> > obj-$(CONFIG_MFD_ATC260X_I2C) += atc260x-i2c.o
> >
> > diff --git a/drivers/mfd/ls2k-bmc-core.c b/drivers/mfd/ls2k-bmc-core.c
> > new file mode 100644
> > index 000000000000..50d560a4611c
> > --- /dev/null
> > +++ b/drivers/mfd/ls2k-bmc-core.c
> > @@ -0,0 +1,156 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/*
> > + * Loongson-2K Board Management Controller (BMC) Core Driver.
> > + *
> > + * Copyright (C) 2024-2025 Loongson Technology Corporation Limited.
> > + *
> > + * Authors:
> > + * Chong Qiao <qiaochong@loongson.cn>
> > + * Binbin Zhou <zhoubinbin@loongson.cn>
> > + */
> > +
> > +#include <linux/aperture.h>
> > +#include <linux/errno.h>
> > +#include <linux/init.h>
> > +#include <linux/kernel.h>
> > +#include <linux/mfd/core.h>
> > +#include <linux/module.h>
> > +#include <linux/pci.h>
> > +#include <linux/pci_ids.h>
> > +#include <linux/platform_data/simplefb.h>
> > +#include <linux/platform_device.h>
> > +
> > +/* LS2K BMC resources */
> > +#define LS2K_DISPLAY_RES_START (SZ_16M + SZ_2M)
> > +#define LS2K_IPMI_RES_SIZE 0x1C
> > +#define LS2K_IPMI0_RES_START (SZ_16M + 0xF00000)
> > +#define LS2K_IPMI1_RES_START (LS2K_IPMI0_RES_START + LS2K_IPMI_RES_SIZE)
> > +#define LS2K_IPMI2_RES_START (LS2K_IPMI1_RES_START + LS2K_IPMI_RES_SIZE)
> > +#define LS2K_IPMI3_RES_START (LS2K_IPMI2_RES_START + LS2K_IPMI_RES_SIZE)
> > +#define LS2K_IPMI4_RES_START (LS2K_IPMI3_RES_START + LS2K_IPMI_RES_SIZE)
> > +
> > +static struct resource ls2k_display_resources[] = {
> > + DEFINE_RES_MEM_NAMED(LS2K_DISPLAY_RES_START, SZ_4M, "simpledrm-res"),
> > +};
> > +
> > +static struct resource ls2k_ipmi0_resources[] = {
> > + DEFINE_RES_MEM_NAMED(LS2K_IPMI0_RES_START, LS2K_IPMI_RES_SIZE, "ipmi0-res"),
> > +};
> > +
> > +static struct resource ls2k_ipmi1_resources[] = {
> > + DEFINE_RES_MEM_NAMED(LS2K_IPMI1_RES_START, LS2K_IPMI_RES_SIZE, "ipmi1-res"),
> > +};
> > +
> > +static struct resource ls2k_ipmi2_resources[] = {
> > + DEFINE_RES_MEM_NAMED(LS2K_IPMI2_RES_START, LS2K_IPMI_RES_SIZE, "ipmi2-res"),
> > +};
> > +
> > +static struct resource ls2k_ipmi3_resources[] = {
> > + DEFINE_RES_MEM_NAMED(LS2K_IPMI3_RES_START, LS2K_IPMI_RES_SIZE, "ipmi3-res"),
> > +};
> > +
> > +static struct resource ls2k_ipmi4_resources[] = {
> > + DEFINE_RES_MEM_NAMED(LS2K_IPMI4_RES_START, LS2K_IPMI_RES_SIZE, "ipmi4-res"),
> > +};
> > +
> > +static struct mfd_cell ls2k_bmc_cells[] = {
> > + MFD_CELL_RES("simple-framebuffer", ls2k_display_resources),
> > + MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi0_resources),
> > + MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi1_resources),
> > + MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi2_resources),
> > + MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi3_resources),
> > + MFD_CELL_RES("ls2k-ipmi-si", ls2k_ipmi4_resources),
> > +};
> > +
> > +/*
> > + * Currently the Loongson-2K BMC hardware does not have an I2C interface to adapt to the
> > + * resolution. We set the resolution by presetting "video=1280x1024-16@2M" to the BMC memory.
> > + */
> > +static int ls2k_bmc_parse_mode(struct pci_dev *pdev, struct simplefb_platform_data *pd)
> > +{
> > + char *mode;
> > + int depth, ret;
> > +
> > + /* The last 16M of PCI BAR0 is used to store the resolution string. */
> > + mode = devm_ioremap(&pdev->dev, pci_resource_start(pdev, 0) + SZ_16M, SZ_16M);
> > + if (!mode)
> > + return -ENOMEM;
> > +
> > + /* The resolution field starts with the flag "video=". */
> > + if (!strncmp(mode, "video=", 6))
> > + mode = mode + 6;
> > +
> > + ret = kstrtoint(strsep(&mode, "x"), 10, &pd->width);
> > + if (ret)
> > + return ret;
> > +
> > + ret = kstrtoint(strsep(&mode, "-"), 10, &pd->height);
> > + if (ret)
> > + return ret;
> > +
> > + ret = kstrtoint(strsep(&mode, "@"), 10, &depth);
> > + if (ret)
> > + return ret;
> > +
> > + pd->stride = pd->width * depth / 8;
> > + pd->format = depth == 32 ? "a8r8g8b8" : "r5g6b5";
> > +
> > + return 0;
> > +}
> > +
> > +static int ls2k_bmc_probe(struct pci_dev *dev, const struct pci_device_id *id)
> > +{
> > + struct simplefb_platform_data pd;
> > + resource_size_t base;
> > + int ret;
> > +
> > + ret = pci_enable_device(dev);
> > + if (ret)
> > + return ret;
> > +
> > + ret = ls2k_bmc_parse_mode(dev, &pd);
> > + if (ret)
> > + goto disable_pci;
> > +
> > + ls2k_bmc_cells[0].platform_data = &pd;
> > + ls2k_bmc_cells[0].pdata_size = sizeof(pd);
>
> This is fragile.
>
> Please identify the elements in ls2k_bmc_cells and use it to index here.
>
> See: `static struct mfd_cell as3711_subdevs`
How about this:
enum {
LS2K_BMC_DISPLAY,
LS2k_BMC_IPMI0,
LS2k_BMC_IPMI1,
LS2k_BMC_IPMI2,
LS2k_BMC_IPMI3,
LS2k_BMC_IPMI4,
};
static struct mfd_cell ls2k_bmc_cells[] = {
[LS2K_BMC_DISPLAY] = {
.name = "simple-framebuffer",
.num_resources = ARRAY_SIZE(ls2k_display_resources),
.resources = ls2k_display_resources
},
[LS2k_BMC_IPMI0] = {
.name = "ls2k-ipmi-si",
.num_resources = ARRAY_SIZE(ls2k_ipmi0_resources),
.resources = ls2k_ipmi0_resources
},
[LS2k_BMC_IPMI1] = {
.name = "ls2k-ipmi-si",
.num_resources = ARRAY_SIZE(ls2k_ipmi1_resources),
.resources = ls2k_ipmi1_resources
},
[LS2k_BMC_IPMI2] = {
.name = "ls2k-ipmi-si",
.num_resources = ARRAY_SIZE(ls2k_ipmi2_resources),
.resources = ls2k_ipmi2_resources
},
[LS2k_BMC_IPMI3] = {
.name = "ls2k-ipmi-si",
.num_resources = ARRAY_SIZE(ls2k_ipmi3_resources),
.resources = ls2k_ipmi3_resources
},
[LS2k_BMC_IPMI4] = {
.name = "ls2k-ipmi-si",
.num_resources = ARRAY_SIZE(ls2k_ipmi4_resources),
.resources = ls2k_ipmi4_resources
},
};
and
ls2k_bmc_cells[LS2K_BMC_DISPLAY].platform_data = &pd;
ls2k_bmc_cells[LS2K_BMC_DISPLAY].pdata_size = sizeof(pd);
>
> > + base = dev->resource[0].start + LS2K_DISPLAY_RES_START;
> > +
> > + /* Remove conflicting efifb device */
> > + ret = aperture_remove_conflicting_devices(base, SZ_4M, "simple-framebuffer");
> > + if (ret) {
> > + dev_err(&dev->dev, "Failed to removed firmware framebuffers: %d\n", ret);
> > + goto disable_pci;
> > + }
> > +
> > + return devm_mfd_add_devices(&dev->dev, PLATFORM_DEVID_AUTO,
> > + ls2k_bmc_cells, ARRAY_SIZE(ls2k_bmc_cells),
> > + &dev->resource[0], 0, NULL);
> > +
> > +disable_pci:
> > + pci_disable_device(dev);
> > + return ret;
> > +}
> > +
> > +static void ls2k_bmc_remove(struct pci_dev *dev)
> > +{
> > + pci_disable_device(dev);
> > +}
> > +
> > +static struct pci_device_id ls2k_bmc_devices[] = {
> > + { PCI_DEVICE(PCI_VENDOR_ID_LOONGSON, 0x1a05) },
> > + { }
> > +};
> > +MODULE_DEVICE_TABLE(pci, ls2k_bmc_devices);
> > +
> > +static struct pci_driver ls2k_bmc_driver = {
> > + .name = "ls2k-bmc",
> > + .id_table = ls2k_bmc_devices,
> > + .probe = ls2k_bmc_probe,
> > + .remove = ls2k_bmc_remove,
> > +};
> > +module_pci_driver(ls2k_bmc_driver);
> > +
> > +MODULE_DESCRIPTION("Loongson-2K Board Management Controller (BMC) Core driver");
> > +MODULE_AUTHOR("Loongson Technology Corporation Limited");
> > +MODULE_LICENSE("GPL");
> > --
> > 2.47.1
> >
>
> --
> Lee Jones [李琼斯]
--
Thanks.
Binbin
On Fri, 11 Jul 2025, Binbin Zhou wrote:
> Hi Lee:
>
> Thanks for your review.
>
> On Thu, Jul 10, 2025 at 5:56 PM Lee Jones <lee@kernel.org> wrote:
> >
> > On Fri, 04 Jul 2025, Binbin Zhou wrote:
> >
> > > The Loongson-2K Board Management Controller provides an PCIe interface
> > > to the host to access the feature implemented in the BMC.
> > >
> > > The BMC is assembled on a server similar to the server machine with
> > > Loongson-3 CPU. It supports multiple sub-devices like DRM and IPMI.
> > >
> > > Co-developed-by: Chong Qiao <qiaochong@loongson.cn>
> > > Signed-off-by: Chong Qiao <qiaochong@loongson.cn>
> > > Reviewed-by: Huacai Chen <chenhuacai@loongson.cn>
> > > Acked-by: Corey Minyard <corey@minyard.net>
> > > Signed-off-by: Binbin Zhou <zhoubinbin@loongson.cn>
> > > ---
> > > MAINTAINERS | 6 ++
> > > drivers/mfd/Kconfig | 13 +++
> > > drivers/mfd/Makefile | 2 +
> > > drivers/mfd/ls2k-bmc-core.c | 156 ++++++++++++++++++++++++++++++++++++
> > > 4 files changed, 177 insertions(+)
[...]
> > > +static int ls2k_bmc_probe(struct pci_dev *dev, const struct pci_device_id *id)
> > > +{
> > > + struct simplefb_platform_data pd;
> > > + resource_size_t base;
> > > + int ret;
> > > +
> > > + ret = pci_enable_device(dev);
> > > + if (ret)
> > > + return ret;
> > > +
> > > + ret = ls2k_bmc_parse_mode(dev, &pd);
> > > + if (ret)
> > > + goto disable_pci;
> > > +
> > > + ls2k_bmc_cells[0].platform_data = &pd;
> > > + ls2k_bmc_cells[0].pdata_size = sizeof(pd);
> >
> > This is fragile.
> >
> > Please identify the elements in ls2k_bmc_cells and use it to index here.
> >
> > See: `static struct mfd_cell as3711_subdevs`
>
> How about this:
>
> enum {
> LS2K_BMC_DISPLAY,
> LS2k_BMC_IPMI0,
> LS2k_BMC_IPMI1,
> LS2k_BMC_IPMI2,
> LS2k_BMC_IPMI3,
> LS2k_BMC_IPMI4,
> };
>
> static struct mfd_cell ls2k_bmc_cells[] = {
> [LS2K_BMC_DISPLAY] = {
> .name = "simple-framebuffer",
> .num_resources = ARRAY_SIZE(ls2k_display_resources),
> .resources = ls2k_display_resources
> },
> [LS2k_BMC_IPMI0] = {
> .name = "ls2k-ipmi-si",
> .num_resources = ARRAY_SIZE(ls2k_ipmi0_resources),
> .resources = ls2k_ipmi0_resources
> },
> [LS2k_BMC_IPMI1] = {
> .name = "ls2k-ipmi-si",
> .num_resources = ARRAY_SIZE(ls2k_ipmi1_resources),
> .resources = ls2k_ipmi1_resources
> },
> [LS2k_BMC_IPMI2] = {
> .name = "ls2k-ipmi-si",
> .num_resources = ARRAY_SIZE(ls2k_ipmi2_resources),
> .resources = ls2k_ipmi2_resources
> },
> [LS2k_BMC_IPMI3] = {
> .name = "ls2k-ipmi-si",
> .num_resources = ARRAY_SIZE(ls2k_ipmi3_resources),
> .resources = ls2k_ipmi3_resources
> },
> [LS2k_BMC_IPMI4] = {
> .name = "ls2k-ipmi-si",
> .num_resources = ARRAY_SIZE(ls2k_ipmi4_resources),
> .resources = ls2k_ipmi4_resources
> },
> };
>
> and
>
> ls2k_bmc_cells[LS2K_BMC_DISPLAY].platform_data = &pd;
> ls2k_bmc_cells[LS2K_BMC_DISPLAY].pdata_size = sizeof(pd);
Yes, that's it.
--
Lee Jones [李琼斯]
© 2016 - 2025 Red Hat, Inc.