[PATCH v2 1/4] Add eSPI device driver (flash channel)
Krzysztof Kozlowski
krzysztof.kozlowski at linaro.org
Tue Mar 19 02:49:20 PDT 2024
On 19/03/2024 10:34, Manojkiran Eda wrote:
> This patch adds the driver support for the eSPI controller of
> Aspeed 5/6th generation SoCs. This controller is a slave device
> communicating with a master over Enhanced Serial Peripheral
> Interface (eSPI).
>
> eSPI supports 4 channels, namely peripheral, virtual wire,
> out-of-band, and flash, and operates at max frequency of 66MHz.
>
> But at the moment, this patch set only supports the mafs mode
> (master attached flash sharing mode) in the flash channel.
>
> Signed-off-by: Manojkiran Eda <manojkiran.eda at gmail.com>
> ---
> drivers/soc/aspeed/Kconfig | 38 ++
> drivers/soc/aspeed/Makefile | 2 +
> drivers/soc/aspeed/aspeed-espi-ctrl.c | 197 +++++++++
> drivers/soc/aspeed/aspeed-espi-ctrl.h | 169 +++++++
> drivers/soc/aspeed/aspeed-espi-flash-mafs.c | 467 ++++++++++++++++++++
> drivers/soc/aspeed/aspeed-espi-flash.h | 71 +++
> 6 files changed, 944 insertions(+)
> create mode 100644 drivers/soc/aspeed/aspeed-espi-ctrl.c
> create mode 100644 drivers/soc/aspeed/aspeed-espi-ctrl.h
> create mode 100644 drivers/soc/aspeed/aspeed-espi-flash-mafs.c
> create mode 100644 drivers/soc/aspeed/aspeed-espi-flash.h
>
> diff --git a/drivers/soc/aspeed/Kconfig b/drivers/soc/aspeed/Kconfig
> index f579ee0b5afa..c300ee8fe33a 100644
> --- a/drivers/soc/aspeed/Kconfig
> +++ b/drivers/soc/aspeed/Kconfig
> @@ -52,6 +52,44 @@ config ASPEED_SOCINFO
> help
> Say yes to support decoding of ASPEED BMC information.
>
> +menu "ASPEED eSPI Support"
> +
> +config ASPEED_ESPI
> + bool "ASPEED eSPI slave driver"
Why this is not tristate?
> + select REGMAP
> + select MFD_SYSCON
> + depends on ASPEED_ESPI_FLASH
> + default n
> + help
> + Enable driver support for the Aspeed eSPI engine. The eSPI engine
> + plays as a slave device in BMC to communicate with the Host over
> + the eSPI interface.
> +
> +menu "ASPEED eSPI Flash channel support"
You have way too many menus...
> +
> +config ASPEED_ESPI_FLASH
This is not used, drop.
> + bool "ASPEED eSPI flash channel support"
> + default n
> + depends on ASPEED_ESPI_FLASH_MAFS
> + select ASPEED_ESPI
> + help
> + Enable eSPI flash channel support.
> +
> +menu "ASPEED eSPI flash modes"
> +
> +config ASPEED_ESPI_FLASH_MAFS
> + bool "Master attached flash sharing (MAFS) support in eSPI"
Why this is not tristate?
> + default n
> + select ASPEED_ESPI_FLASH
> + help
> + Select this option if you have a Master attached flash connected to
> + the eSPI controller.
> +
> +endmenu # eSPI Flash Modes
> +endmenu # eSPI Flash Channel support
> +endmenu # eSPI Support
> +
> +
> endmenu
>
> endif
> diff --git a/drivers/soc/aspeed/Makefile b/drivers/soc/aspeed/Makefile
> index b35d74592964..cecbba700071 100644
> --- a/drivers/soc/aspeed/Makefile
> +++ b/drivers/soc/aspeed/Makefile
> @@ -4,3 +4,5 @@ obj-$(CONFIG_ASPEED_LPC_SNOOP) += aspeed-lpc-snoop.o
> obj-$(CONFIG_ASPEED_UART_ROUTING) += aspeed-uart-routing.o
> obj-$(CONFIG_ASPEED_P2A_CTRL) += aspeed-p2a-ctrl.o
> obj-$(CONFIG_ASPEED_SOCINFO) += aspeed-socinfo.o
> +obj-$(CONFIG_ASPEED_ESPI) += aspeed-espi-ctrl.o
> +obj-$(CONFIG_ASPEED_ESPI_FLASH_MAFS) += aspeed-espi-flash-mafs.o
Why did you put spi drivers in soc? SPI drivers usually go to spi, don't
they?
> diff --git a/drivers/soc/aspeed/aspeed-espi-ctrl.c b/drivers/soc/aspeed/aspeed-espi-ctrl.c
> new file mode 100644
> index 000000000000..7e2b86849fd0
> --- /dev/null
> +++ b/drivers/soc/aspeed/aspeed-espi-ctrl.c
> @@ -0,0 +1,197 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +/*
> + * Copyright 2024 Aspeed Technology Inc.
> + */
> +#include <linux/io.h>
> +#include <linux/irq.h>
> +#include <linux/clk.h>
> +#include <linux/module.h>
> +#include <linux/of_device.h>
> +#include <linux/interrupt.h>
> +#include <linux/platform_device.h>
> +#include <linux/miscdevice.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +#include <linux/uaccess.h>
> +#include <linux/vmalloc.h>
> +
> +#include "aspeed-espi-ctrl.h"
> +#include "aspeed-espi-flash.h"
> +
> +/**
No need for kerneldoc for private functions.
> + * aspeed_espi_ctrl_isr - function to handle various interrupts
> + * @irq: interrupt line
> + * @arg: pointer to access device registers
> + *
> + * Returns IRQ_HANDLED
> + */
> +static irqreturn_t aspeed_espi_ctrl_isr(int irq, void *arg)
> +{
> + uint32_t sts;
> + struct aspeed_espi_ctrl *espi_ctrl = (struct aspeed_espi_ctrl *)arg;
> +
> + regmap_read(espi_ctrl->map, ESPI_INT_STS, &sts);
> +
> + if (sts & ESPI_INT_STS_FLASH_BITS) {
> + aspeed_espi_flash_event(sts, espi_ctrl->flash);
> + regmap_write(espi_ctrl->map, ESPI_INT_STS,
> + sts & ESPI_INT_STS_FLASH_BITS);
> + }
> +
> + if (sts & ESPI_INT_STS_HW_RST_DEASSERT) {
> + aspeed_espi_flash_enable(espi_ctrl->flash);
> +
> + regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_T0, 0x0);
> + regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_T1, 0x0);
> + regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_EN, 0xffffffff);
> +
> + regmap_write(espi_ctrl->map, ESPI_SYSEVT1_INT_T0, 0x1);
> + regmap_write(espi_ctrl->map, ESPI_SYSEVT1_INT_EN, 0x1);
> +
> + regmap_update_bits(espi_ctrl->map, ESPI_INT_EN,
> + ESPI_INT_EN_HW_RST_DEASSERT,
> + ESPI_INT_EN_HW_RST_DEASSERT);
> +
> + regmap_update_bits(
> + espi_ctrl->map, ESPI_SYSEVT,
> + ESPI_SYSEVT_SLV_BOOT_STS | ESPI_SYSEVT_SLV_BOOT_DONE,
> + ESPI_SYSEVT_SLV_BOOT_STS | ESPI_SYSEVT_SLV_BOOT_DONE);
> +
> + regmap_write(espi_ctrl->map, ESPI_INT_STS,
> + ESPI_INT_STS_HW_RST_DEASSERT);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +/**
> + * aspeed_espi_ctrl_probe - function to probe the platform driver
> + * @pdev: platform device
> + *
> + * Returns 0 on success, -ENOMEM on error
Drop useless kerneldoc / entire function comment. That's just probe...
> + */
> +static int aspeed_espi_ctrl_probe(struct platform_device *pdev)
> +{
> + int rc = 0;
> + struct aspeed_espi_ctrl *espi_ctrl;
> + struct device *dev = &pdev->dev;
> +
> + espi_ctrl = devm_kzalloc(dev, sizeof(*espi_ctrl), GFP_KERNEL);
> + if (!espi_ctrl)
> + return -ENOMEM;
> +
> + espi_ctrl->model = of_device_get_match_data(dev);
> +
> + espi_ctrl->map = syscon_node_to_regmap(dev->parent->of_node);
> + if (IS_ERR(espi_ctrl->map)) {
> + dev_err(dev, "cannot get remap\n");
> + return PTR_ERR(espi_ctrl->map);
return dev_err_probe
> + }
> +
> + espi_ctrl->irq = platform_get_irq(pdev, 0);
> + if (espi_ctrl->irq < 0)
> + return espi_ctrl->irq;
> +
> + espi_ctrl->clk = devm_clk_get(dev, NULL);
> + if (IS_ERR(espi_ctrl->clk)) {
> + dev_err(dev, "cannot get clock\n");
> + return PTR_ERR(espi_ctrl->clk);
return dev_err_probe
> + }
> +
> + rc = clk_prepare_enable(espi_ctrl->clk);
> + if (rc) {
> + dev_err(dev, "cannot enable clock\n");
> + return rc;
> + }
> +
> + /*
> + * This takes care of deferred probe , incase the mtd core
> + * subsystem is not probed yet.
> + */
> + espi_ctrl->flash = aspeed_espi_flash_alloc(dev, espi_ctrl);
> + if (IS_ERR(espi_ctrl->flash)) {
> + dev_err(dev, "failed to allocate flash channel\n");
> + pr_info("flash alloc failed with return code %ld\n",
> + PTR_ERR(espi_ctrl->flash));
Please clean up the code. Drop.
> + return PTR_ERR(espi_ctrl->flash);
> + }
> +
> + regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_T0, 0x0);
> + regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_T1, 0x0);
> + regmap_write(espi_ctrl->map, ESPI_SYSEVT_INT_EN, 0xffffffff);
> +
> + regmap_write(espi_ctrl->map, ESPI_SYSEVT1_INT_T0, 0x1);
> + regmap_write(espi_ctrl->map, ESPI_SYSEVT1_INT_EN, 0x1);
> +
> + rc = devm_request_irq(dev, espi_ctrl->irq, aspeed_espi_ctrl_isr, 0,
> + DEVICE_NAME, espi_ctrl);
> + if (rc) {
> + dev_err(dev, "failed to request IRQ\n");
> + return rc;
> + }
> +
> + // clear the interrupt enable register
> + regmap_write(espi_ctrl->map, ESPI_INT_EN_CLR, 0x7fffffff);
> +
> + // Disable the interrupts in all channels except flash channel
> + regmap_update_bits(espi_ctrl->map, ESPI_INT_EN,
> + ESPI_INT_EN_FLASH_BITS | ESPI_INT_EN_HW_RST_DEASSERT,
> + ESPI_INT_EN_FLASH_BITS |
> + ESPI_INT_STS_HW_RST_DEASSERT);
Why do you first request interrupt and then disable them? What if it
fires earlier?
> +
> + dev_set_drvdata(dev, espi_ctrl);
> +
> + dev_info(dev, "module loaded\n");
No, drop such simple function success statements.
> +
> + return 0;
> +}
> +
> +/**
> + * aspeed_espi_ctrl_remove - Release the driver
> + * @pdev: the platform device
> + *
> + * Returns 0
> + */
Drop entire comment, useless.
...
> +
> +void *aspeed_espi_flash_alloc(struct device *dev,
> + struct aspeed_espi_ctrl *espi_ctrl)
> +{
> + int ret, index;
> + struct aspeed_espi_flash_dma *dma;
> + struct mtd_info *mtd;
> + struct aspeed_espi_flash *espi_flash;
> + struct resource res;
> + u32 reg;
> +
> + espi_flash =
> + devm_kzalloc(dev, sizeof(struct aspeed_espi_flash), GFP_KERNEL);
sizeof(*)
> + if (!espi_flash)
> + return ERR_PTR(-ENOMEM);
> +
> + espi_flash->ctrl = espi_ctrl;
> +
> + /* Bus lock */
> + mutex_init(&espi_flash->lock);
> +
> + init_waitqueue_head(&espi_flash->wq);
> +
> + spin_lock_init(&espi_flash->spinlock);
> +
> + dma = &espi_flash->dma;
> +
> + dma->tx_virt =
> + dma_alloc_coherent(dev, PAGE_SIZE, &dma->tx_addr, GFP_KERNEL);
Wrong wrapping.
> + if (!dma->tx_virt) {
> + dev_err(dev, "cannot allocate DMA TX buffer\n");
Do not print anything on allocation failures.
> + return ERR_PTR(-ENOMEM);
> + }
> +
> + dma->rx_virt =
> + dma_alloc_coherent(dev, PAGE_SIZE, &dma->rx_addr, GFP_KERNEL);
> + if (!dma->rx_virt) {
> + dev_err(dev, "cannot allocate DMA RX buffer\n");
Drop
> + return ERR_PTR(-ENOMEM);
> + }
> + index = of_property_match_string(dev->of_node, "reg-names",
> + "espi_flash");
> + ret = of_address_to_resource(dev->of_node, index, &res);
Why such unusual code? Why you cannot just map the io space?
> + if (ret < 0) {
> + dev_err(dev,
> + "Could not find espi_flash resource block size in devtree\n");
> + return ERR_PTR(-ENODEV);
> + }
> + reg = resource_size(&res);
> + mtd = &espi_flash->mtd;
> + mtd->dev.parent = dev;
> + mtd->size = reg;
> + mtd->flags = MTD_CAP_NORFLASH;
> + mtd->_erase = aspeed_espi_flash_erase;
> + mtd->_read = aspeed_espi_flash_read;
> + mtd->_write = aspeed_espi_flash_write;
> + mtd->type = MTD_NORFLASH;
> + mtd->name = "espi-flash-mafs";
> +
> + regmap_read(espi_ctrl->map, ESPI_CH3_CAP_N_CONF, ®);
> + reg = (reg & ESPI_CH3_CAP_N_CONF_ERASE_MASK) >>
> + ESPI_CH3_CAP_N_CONF_ERASE_SHIFT;
> + espi_flash->erase_mask = reg;
> + switch (reg) {
> + case ESPI_CH3_CAP_N_CONF_ERASE_SIZE_4KB:
> + case ESPI_CH3_CAP_N_CONF_ERASE_SIZE_4KB_64KB:
> + mtd->erasesize = 0x1000;
> + espi_flash->erase_mask = 1;
> + break;
> + case ESPI_CH3_CAP_N_CONF_ERASE_SIZE_64KB:
> + mtd->erasesize = 0x10000;
> + break;
> + case ESPI_CH3_CAP_N_CONF_ERASE_SIZE_128KB:
> + mtd->erasesize = 0x20000;
> + break;
> + case ESPI_CH3_CAP_N_CONF_ERASE_SIZE_256KB:
> + mtd->erasesize = 0x40000;
> + break;
> + default:
> + dev_notice(dev, "Unknown erase size %x\n", reg);
> + return ERR_PTR(-ENODEV);
> + }
> +
> + mtd->writesize = 1;
> + mtd->owner = THIS_MODULE;
> + mtd->priv = espi_flash;
> +
> + ret = mtd_device_register(mtd, NULL, 0);
> + if (ret) {
> + dev_notice(dev, "aspeed-espi-mtd: Failed to register mtd device\n");
> + return ERR_PTR(ret);
> + }
> +
> + aspeed_espi_flash_enable(espi_flash);
> + return espi_flash;
> +}
Missing export as GPL
> +
> +void aspeed_espi_flash_free(struct device *dev,
> + struct aspeed_espi_flash *espi_flash)
> +{
> + struct aspeed_espi_flash_dma *dma = &espi_flash->dma;
> +
> + dma_free_coherent(dev, PAGE_SIZE, dma->tx_virt, dma->tx_addr);
> + dma_free_coherent(dev, PAGE_SIZE, dma->rx_virt, dma->rx_addr);
> +
> + mtd_device_unregister(&espi_flash->mtd);
> +}
Missing export as GPL
Best regards,
Krzysztof
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