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Message-ID: <20250522092208.GB1199143@google.com>
Date: Thu, 22 May 2025 10:22:08 +0100
From: Lee Jones <lee@...nel.org>
To: Binbin Zhou <zhoubinbin@...ngson.cn>
Cc: Binbin Zhou <zhoubb.aaron@...il.com>,
Huacai Chen <chenhuacai@...ngson.cn>,
Corey Minyard <minyard@....org>,
Huacai Chen <chenhuacai@...nel.org>,
Xuerui Wang <kernel@...0n.name>, loongarch@...ts.linux.dev,
linux-kernel@...r.kernel.org,
openipmi-developer@...ts.sourceforge.net,
Chong Qiao <qiaochong@...ngson.cn>
Subject: Re: [PATCH v2 1/3] mfd: ls2kbmc: Introduce Loongson-2K BMC MFD Core
driver
Just "core driver" in the subject line, rather than "MFD core driver".
> 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-3C6000 CPUs. It supports multiple sub-devices like DRM.
>
> Co-developed-by: Chong Qiao <qiaochong@...ngson.cn>
> Signed-off-by: Chong Qiao <qiaochong@...ngson.cn>
> Signed-off-by: Binbin Zhou <zhoubinbin@...ngson.cn>
> ---
> drivers/mfd/Kconfig | 13 ++++
> drivers/mfd/Makefile | 2 +
> drivers/mfd/ls2kbmc-mfd.c | 156 ++++++++++++++++++++++++++++++++++++++
> 3 files changed, 171 insertions(+)
> create mode 100644 drivers/mfd/ls2kbmc-mfd.c
>
> diff --git a/drivers/mfd/Kconfig b/drivers/mfd/Kconfig
> index 22b936310039..04e40085441d 100644
> --- a/drivers/mfd/Kconfig
> +++ b/drivers/mfd/Kconfig
> @@ -2422,5 +2422,18 @@ config MFD_UPBOARD_FPGA
> To compile this driver as a module, choose M here: the module will be
> called upboard-fpga.
>
> +config MFD_LS2K_BMC
> + tristate "Loongson-2K Board Management Controller Support"
> + depends on LOONGARCH
> + default y if LOONGARCH
> + 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 DRM.
> + This driver provides common support for accessing the devices;
> + additional drivers must be enabled in order to use the
> + functionality of the BMC device.
This paragraph has some odd line breaks. Please re-align.
> endmenu
> endif
> diff --git a/drivers/mfd/Makefile b/drivers/mfd/Makefile
> index 948cbdf42a18..18960ea13b64 100644
> --- a/drivers/mfd/Makefile
> +++ b/drivers/mfd/Makefile
> @@ -290,3 +290,5 @@ obj-$(CONFIG_MFD_RSMU_I2C) += rsmu_i2c.o rsmu_core.o
> obj-$(CONFIG_MFD_RSMU_SPI) += rsmu_spi.o rsmu_core.o
>
> obj-$(CONFIG_MFD_UPBOARD_FPGA) += upboard-fpga.o
> +
> +obj-$(CONFIG_MFD_LS2K_BMC) += ls2kbmc-mfd.o
> diff --git a/drivers/mfd/ls2kbmc-mfd.c b/drivers/mfd/ls2kbmc-mfd.c
> new file mode 100644
> index 000000000000..b309f6132c24
> --- /dev/null
> +++ b/drivers/mfd/ls2kbmc-mfd.c
> @@ -0,0 +1,156 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Loongson-2K Board Management Controller (BMC) MFD Core Driver.
Remove the MFD part. It's not a thing - we made it up.
> + * Copyright (C) 2024 Loongson Technology Corporation Limited.
No changes since 2024?
> + *
> + * Originally written by Chong Qiao <qiaochong@...ngson.cn>
> + * Rewritten for mainline by Binbin Zhou <zhoubinbin@...ngson.cn>
"Mainline"
Typically we just do:
Authors:
Author One <one@...p.com>
Author Two <two@...p.com>
> + */
> +
> +#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>
> +
> +#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)
Line them _all_ up please. One more tab should do it.
> +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-2K0500 BMC hardware does not have an i2c interface to
I2C
> + * adapt to the resolution.
Remove the line break here.
> + * We set the resolution by presetting "video=1280x1024-16@2M" to the bmc memory.
BMC
> + */
> +static int ls2k_bmc_get_video_mode(struct pci_dev *pdev, struct simplefb_platform_data *pd)
> +{
> + char *mode;
> + int depth, ret;
> +
> + /* The pci mem bar last 16M is used to store the string. */
PCI
BAR's (maybe?)
> + mode = devm_ioremap(&pdev->dev, pci_resource_start(pdev, 0) + SZ_16M, SZ_16M);
> + if (!mode)
> + return -ENOMEM;
> +
> + /* env at last 16M's beginning, first env is "video=" */
This doesn't make sense to me - please reword.
> + 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;
> +}
Surely there is a standard format / API for this already?
> +static int ls2k_bmc_probe(struct pci_dev *dev, const struct pci_device_id *id)
> +{
> + int ret = 0;
There is no need to pre-initialise this.
> + resource_size_t base;
> + struct simplefb_platform_data pd;
Reverse these please (reverse Christmas tree is preferred).
> +
> + ret = pci_enable_device(dev);
> + if (ret)
> + return ret;
> +
> + ret = ls2k_bmc_get_video_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, "Remove firmware framebuffers failed: %d\n", ret);
"Failed to removed firmware framebuffers"
> + 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,
> +};
> +
Remove this line.
> +module_pci_driver(ls2k_bmc_driver);
> +
> +MODULE_DESCRIPTION("Loongson-2K BMC driver");
> +MODULE_AUTHOR("Loongson Technology Corporation Limited");
> +MODULE_LICENSE("GPL");
> --
> 2.47.1
>
--
Lee Jones [李琼斯]
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