Subject: Re: [PATCH v2 09/11] fsi: Add ast2600 master driver

From: Alistair Popple <[email-masked]>
Date: Fri, 08 Nov 2019 20:29:00 +1100

Having a hardware master should make things quicker.

Acked-by: Alistair Popple <[email-masked]>

On Friday, 8 November 2019 4:19:43 PM AEDT Joel Stanley wrote:
> The ast2600 BMC has a pair of FSI masters in it, behind an AHB to OPB
> bridge.
> 
> The master driver supports reads and writes of full words, half word and
> byte accesses to remote CFAMs. It can perform very basic error recovery
> through resetting of the FSI port when an error is detected, and the
> issuing of breaks and terms.
> 
> Signed-off-by: Joel Stanley <[email-masked]>
> --
> v2:
>  - remove debugging
>  - squash in fixes
> ---
>  drivers/fsi/Kconfig             |   8 +
>  drivers/fsi/Makefile            |   1 +
>  drivers/fsi/fsi-master-aspeed.c | 522 ++++++++++++++++++++++++++++++++
>  3 files changed, 531 insertions(+)
>  create mode 100644 drivers/fsi/fsi-master-aspeed.c
> 
> diff --git a/drivers/fsi/Kconfig b/drivers/fsi/Kconfig
> index c612db7a914a..92ce6d85802c 100644
> --- a/drivers/fsi/Kconfig
> +++ b/drivers/fsi/Kconfig
> @@ -53,6 +53,14 @@ config FSI_MASTER_AST_CF
>  	lines driven by the internal ColdFire coprocessor. This requires
>  	the corresponding machine specific ColdFire firmware to be available.
>  
> +config FSI_MASTER_ASPEED
> +	tristate "FSI ASPEED master"
> +	help
> +	 This option enables a FSI master that is present behind an OPB bridge
> +	 in the AST2600.
> +
> +	 Enable it for your BMC kernel in an OpenPower or IBM Power system.
> +
>  config FSI_SCOM
>  	tristate "SCOM FSI client device driver"
>  	---help---
> diff --git a/drivers/fsi/Makefile b/drivers/fsi/Makefile
> index e4a2ff043c32..da218a1ad8e1 100644
> --- a/drivers/fsi/Makefile
> +++ b/drivers/fsi/Makefile
> @@ -2,6 +2,7 @@
>  
>  obj-$(CONFIG_FSI) += fsi-core.o
>  obj-$(CONFIG_FSI_MASTER_HUB) += fsi-master-hub.o
> +obj-$(CONFIG_FSI_MASTER_ASPEED) += fsi-master-aspeed.o
>  obj-$(CONFIG_FSI_MASTER_GPIO) += fsi-master-gpio.o
>  obj-$(CONFIG_FSI_MASTER_AST_CF) += fsi-master-ast-cf.o
>  obj-$(CONFIG_FSI_SCOM) += fsi-scom.o
> diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c
> new file mode 100644
> index 000000000000..d1b83f035483
> --- /dev/null
> +++ b/drivers/fsi/fsi-master-aspeed.c
> @@ -0,0 +1,522 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +// Copyright (C) IBM Corporation 2018
> +// FSI master driver for AST2600
> +
> +#include <linux/clk.h>
> +#include <linux/delay.h>
> +#include <linux/fsi.h>
> +#include <linux/io.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/module.h>
> +#include <linux/of.h>
> +#include <linux/platform_device.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/iopoll.h>
> +
> +#include "fsi-master.h"
> +
> +struct fsi_master_aspeed {
> +	struct fsi_master	master;
> +	struct device		*dev;
> +	void __iomem		*base;
> +	struct clk		*clk;
> +};
> +
> +#define to_fsi_master_aspeed(m) \
> +	container_of(m, struct fsi_master_aspeed, master)
> +
> +/* Control register (size 0x400) */
> +static const u32 ctrl_base = 0x80000000;
> +
> +static const u32 fsi_base = 0xa0000000;
> +
> +#define OPB_FSI_VER	0x00
> +#define OPB_TRIGGER	0x04
> +#define OPB_CTRL_BASE	0x08
> +#define OPB_FSI_BASE	0x0c
> +#define OPB_CLK_SYNC	0x3c
> +#define OPB_IRQ_CLEAR	0x40
> +#define OPB_IRQ_MASK	0x44
> +#define OPB_IRQ_STATUS	0x48
> +
> +#define OPB0_SELECT	0x10
> +#define OPB0_RW		0x14
> +#define OPB0_XFER_SIZE	0x18
> +#define OPB0_FSI_ADDR	0x1c
> +#define OPB0_FSI_DATA_W	0x20
> +#define OPB0_STATUS	0x80
> +#define OPB0_FSI_DATA_R	0x84
> +
> +#define OPB0_WRITE_ORDER1	0x4c
> +#define OPB0_WRITE_ORDER2	0x50
> +#define OPB1_WRITE_ORDER1	0x54
> +#define OPB1_WRITE_ORDER2	0x58
> +#define OPB0_READ_ORDER1	0x5c
> +#define OPB1_READ_ORDER2	0x60
> +
> +#define OPB_RETRY_COUNTER	0x64
> +
> +/* OPBn_STATUS */
> +#define STATUS_HALFWORD_ACK	BIT(0)
> +#define STATUS_FULLWORD_ACK	BIT(1)
> +#define STATUS_ERR_ACK		BIT(2)
> +#define STATUS_RETRY		BIT(3)
> +#define STATUS_TIMEOUT		BIT(4)
> +
> +/* OPB_IRQ_MASK */
> +#define OPB1_XFER_ACK_EN BIT(17)
> +#define OPB0_XFER_ACK_EN BIT(16)
> +
> +/* OPB_RW */
> +#define CMD_READ	BIT(0)
> +#define CMD_WRITE	0
> +
> +/* OPBx_XFER_SIZE */
> +#define XFER_FULLWORD	(BIT(1) | BIT(0))
> +#define XFER_HALFWORD	(BIT(0))
> +#define XFER_BYTE	(0)
> +
> +#define FSI_LINK_ENABLE_SETUP_TIME	10	/* in mS */
> +
> +#define DEFAULT_DIVISOR			14
> +#define OPB_POLL_TIMEOUT		10000
> +
> +static int __opb_write(struct fsi_master_aspeed *aspeed, u32 addr,
> +		       u32 val, u32 transfer_size)
> +{
> +	void __iomem *base = aspeed->base;
> +	u32 reg, status;
> +	int ret;
> +
> +	writel(CMD_WRITE, base + OPB0_RW);
> +	writel(transfer_size, base + OPB0_XFER_SIZE);
> +	writel(addr, base + OPB0_FSI_ADDR);
> +	writel(val, base + OPB0_FSI_DATA_W);
> +	writel(0x1, base + OPB_IRQ_CLEAR);
> +	writel(0x1, base + OPB_TRIGGER);
> +
> +	ret = readl_poll_timeout(base + OPB_IRQ_STATUS, reg,
> +				(reg & OPB0_XFER_ACK_EN) != 0,
> +				0, OPB_POLL_TIMEOUT);
> +
> +	status = readl(base + OPB0_STATUS);
> +
> +	/* Return error when poll timed out */
> +	if (ret)
> +		return ret;
> +
> +	/* Command failed, master will reset */
> +	if (status & STATUS_ERR_ACK)
> +		return -EIO;
> +
> +	return 0;
> +}
> +
> +static int opb_writeb(struct fsi_master_aspeed *aspeed, u32 addr, u8 val)
> +{
> +	return __opb_write(aspeed, addr, val, XFER_BYTE);
> +}
> +
> +static int opb_writew(struct fsi_master_aspeed *aspeed, u32 addr, __be16 val)
> +{
> +	return __opb_write(aspeed, addr, (__force u16)val, XFER_HALFWORD);
> +}
> +
> +static int opb_writel(struct fsi_master_aspeed *aspeed, u32 addr, __be32 val)
> +{
> +	return __opb_write(aspeed, addr, (__force u32)val, XFER_FULLWORD);
> +}
> +
> +static int __opb_read(struct fsi_master_aspeed *aspeed, uint32_t addr,
> +		      u32 transfer_size, void *out)
> +{
> +	void __iomem *base = aspeed->base;
> +	u32 result, reg;
> +	int status, ret;
> +
> +	writel(CMD_READ, base + OPB0_RW);
> +	writel(transfer_size, base + OPB0_XFER_SIZE);
> +	writel(addr, base + OPB0_FSI_ADDR);
> +	writel(0x1, base + OPB_IRQ_CLEAR);
> +	writel(0x1, base + OPB_TRIGGER);
> +
> +	ret = readl_poll_timeout(base + OPB_IRQ_STATUS, reg,
> +			   (reg & OPB0_XFER_ACK_EN) != 0,
> +			   0, OPB_POLL_TIMEOUT);
> +
> +	status = readl(base + OPB0_STATUS);
> +
> +	result = readl(base + OPB0_FSI_DATA_R);
> +
> +	/* Return error when poll timed out */
> +	if (ret)
> +		return ret;
> +
> +	/* Command failed, master will reset */
> +	if (status & STATUS_ERR_ACK)
> +		return -EIO;
> +
> +	if (out) {
> +		switch (transfer_size) {
> +		case XFER_BYTE:
> +			*(u8 *)out = result;
> +			break;
> +		case XFER_HALFWORD:
> +			*(u16 *)out = result;
> +			break;
> +		case XFER_FULLWORD:
> +			*(u32 *)out = result;
> +			break;
> +		default:
> +			return -EINVAL;
> +		}
> +
> +	}
> +
> +	return 0;
> +}
> +
> +static int opb_readl(struct fsi_master_aspeed *aspeed, uint32_t addr, __be32 *out)
> +{
> +	return __opb_read(aspeed, addr, XFER_FULLWORD, out);
> +}
> +
> +static int opb_readw(struct fsi_master_aspeed *aspeed, uint32_t addr, __be16 *out)
> +{
> +	return __opb_read(aspeed, addr, XFER_HALFWORD, (void *)out);
> +}
> +
> +static int opb_readb(struct fsi_master_aspeed *aspeed, uint32_t addr, u8 *out)
> +{
> +	return __opb_read(aspeed, addr, XFER_BYTE, (void *)out);
> +}
> +
> +static int check_errors(struct fsi_master_aspeed *aspeed, int err)
> +{
> +	int ret;
> +
> +	if (err == -EIO) {
> +		/* Check MAEB (0x70) ? */
> +
> +		/* Then clear errors in master */
> +		ret = opb_writel(aspeed, ctrl_base + FSI_MRESP0,
> +				cpu_to_be32(FSI_MRESP_RST_ALL_MASTER));
> +		if (ret) {
> +			/* TODO: log? return different code? */
> +			return ret;
> +		}
> +		/* TODO: confirm that 0x70 was okay */
> +	}
> +
> +	/* This will pass through timeout errors */
> +	return err;
> +}
> +
> +static int aspeed_master_read(struct fsi_master *master, int link,
> +			uint8_t id, uint32_t addr, void *val, size_t size)
> +{
> +	struct fsi_master_aspeed *aspeed = to_fsi_master_aspeed(master);
> +	int ret;
> +
> +	if (id != 0)
> +		return -EINVAL;
> +
> +	addr += link * FSI_HUB_LINK_SIZE;
> +
> +	switch (size) {
> +	case 1:
> +		ret = opb_readb(aspeed, fsi_base + addr, val);
> +		break;
> +	case 2:
> +		ret = opb_readw(aspeed, fsi_base + addr, val);
> +		break;
> +	case 4:
> +		ret = opb_readl(aspeed, fsi_base + addr, val);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ret = check_errors(aspeed, ret);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int aspeed_master_write(struct fsi_master *master, int link,
> +			uint8_t id, uint32_t addr, const void *val, size_t size)
> +{
> +	struct fsi_master_aspeed *aspeed = to_fsi_master_aspeed(master);
> +	int ret;
> +
> +	if (id != 0)
> +		return -EINVAL;
> +
> +	addr += link * FSI_HUB_LINK_SIZE;
> +
> +	switch (size) {
> +	case 1:
> +		ret = opb_writeb(aspeed, fsi_base + addr, *(u8 *)val);
> +		break;
> +	case 2:
> +		ret = opb_writew(aspeed, fsi_base + addr, *(__be16 *)val);
> +		break;
> +	case 4:
> +		ret = opb_writel(aspeed, fsi_base + addr, *(__be32 *)val);
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	ret = check_errors(aspeed, ret);
> +	if (ret)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int aspeed_master_link_enable(struct fsi_master *master, int link)
> +{
> +	struct fsi_master_aspeed *aspeed = to_fsi_master_aspeed(master);
> +	int idx, bit, ret;
> +	__be32 reg, result;
> +
> +	idx = link / 32;
> +	bit = link % 32;
> +
> +	reg = cpu_to_be32(0x80000000 >> bit);
> +
> +	ret = opb_writel(aspeed, ctrl_base + FSI_MSENP0 + (4 * idx), reg);
> +	if (ret)
> +		return ret;
> +
> +	mdelay(FSI_LINK_ENABLE_SETUP_TIME);
> +
> +	ret = opb_readl(aspeed, ctrl_base + FSI_MENP0 + (4 * idx), &result);
> +	if (ret)
> +		return ret;
> +
> +	if (result != reg) {
> +		dev_err(aspeed->dev, "%s failed: %08x\n", __func__, result);
> +		return -EIO;
> +	}
> +
> +	return 0;
> +}
> +
> +static int aspeed_master_term(struct fsi_master *master, int link, uint8_t id)
> +{
> +	uint32_t addr;
> +	__be32 cmd;
> +
> +	addr = 0x4;
> +	cmd = cpu_to_be32(0xecc00000);
> +
> +	return aspeed_master_write(master, link, id, addr, &cmd, 4);
> +}
> +
> +static int aspeed_master_break(struct fsi_master *master, int link)
> +{
> +	uint32_t addr;
> +	__be32 cmd;
> +
> +	addr = 0x0;
> +	cmd = cpu_to_be32(0xc0de0000);
> +
> +	return aspeed_master_write(master, link, 0, addr, &cmd, 4);
> +}
> +
> +static void aspeed_master_release(struct device *dev)
> +{
> +	struct fsi_master_aspeed *aspeed =
> +		to_fsi_master_aspeed(dev_to_fsi_master(dev));
> +
> +	kfree(aspeed);
> +}
> +
> +/* mmode encoders */
> +static inline u32 fsi_mmode_crs0(u32 x)
> +{
> +	return (x & FSI_MMODE_CRS0MASK) << FSI_MMODE_CRS0SHFT;
> +}
> +
> +static inline u32 fsi_mmode_crs1(u32 x)
> +{
> +	return (x & FSI_MMODE_CRS1MASK) << FSI_MMODE_CRS1SHFT;
> +}
> +
> +static int aspeed_master_init(struct fsi_master_aspeed *aspeed)
> +{
> +	__be32 reg;
> +
> +	reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK
> +			| FSI_MRESP_RST_MCR | FSI_MRESP_RST_PYE);
> +	opb_writel(aspeed, ctrl_base + FSI_MRESP0, reg);
> +
> +	/* Initialize the MFSI (hub master) engine */
> +	reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK
> +			| FSI_MRESP_RST_MCR | FSI_MRESP_RST_PYE);
> +	opb_writel(aspeed, ctrl_base + FSI_MRESP0, reg);
> +
> +	reg = cpu_to_be32(FSI_MECTRL_EOAE | FSI_MECTRL_P8_AUTO_TERM);
> +	opb_writel(aspeed, ctrl_base + FSI_MECTRL, reg);
> +
> +	reg = cpu_to_be32(FSI_MMODE_ECRC | FSI_MMODE_EPC | FSI_MMODE_RELA
> +			| fsi_mmode_crs0(DEFAULT_DIVISOR)
> +			| fsi_mmode_crs1(DEFAULT_DIVISOR)
> +			| FSI_MMODE_P8_TO_LSB);
> +	opb_writel(aspeed, ctrl_base + FSI_MMODE, reg);
> +
> +	reg = cpu_to_be32(0xffff0000);
> +	opb_writel(aspeed, ctrl_base + FSI_MDLYR, reg);
> +
> +	reg = cpu_to_be32(~0);
> +	opb_writel(aspeed, ctrl_base + FSI_MSENP0, reg);
> +
> +	/* Leave enabled long enough for master logic to set up */
> +	mdelay(FSI_LINK_ENABLE_SETUP_TIME);
> +
> +	opb_writel(aspeed, ctrl_base + FSI_MCENP0, reg);
> +
> +	opb_readl(aspeed, ctrl_base + FSI_MAEB, NULL);
> +
> +	reg = cpu_to_be32(FSI_MRESP_RST_ALL_MASTER | FSI_MRESP_RST_ALL_LINK);
> +	opb_writel(aspeed, ctrl_base + FSI_MRESP0, reg);
> +
> +	opb_readl(aspeed, ctrl_base + FSI_MLEVP0, NULL);
> +
> +	/* Reset the master bridge */
> +	reg = cpu_to_be32(FSI_MRESB_RST_GEN);
> +	opb_writel(aspeed, ctrl_base + FSI_MRESB0, reg);
> +
> +	reg = cpu_to_be32(FSI_MRESB_RST_ERR);
> +	opb_writel(aspeed, ctrl_base + FSI_MRESB0, reg);
> +
> +	return 0;
> +}
> +
> +static int fsi_master_aspeed_probe(struct platform_device *pdev)
> +{
> +	struct fsi_master_aspeed *aspeed;
> +	struct resource *res;
> +	int rc, links, reg;
> +	__be32 raw;
> +
> +	aspeed = devm_kzalloc(&pdev->dev, sizeof(*aspeed), GFP_KERNEL);
> +	if (!aspeed)
> +		return -ENOMEM;
> +
> +	aspeed->dev = &pdev->dev;
> +
> +	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> +	aspeed->base = devm_ioremap_resource(&pdev->dev, res);
> +	if (IS_ERR(aspeed->base))
> +		return PTR_ERR(aspeed->base);
> +
> +	aspeed->clk = devm_clk_get(aspeed->dev, NULL);
> +	if (IS_ERR(aspeed->clk)) {
> +		dev_err(aspeed->dev, "couldn't get clock\n");
> +		return PTR_ERR(aspeed->clk);
> +	}
> +	rc = clk_prepare_enable(aspeed->clk);
> +	if (rc) {
> +		dev_err(aspeed->dev, "couldn't enable clock\n");
> +		return rc;
> +	}
> +
> +	writel(0x1, aspeed->base + OPB_CLK_SYNC);
> +	writel(OPB1_XFER_ACK_EN | OPB0_XFER_ACK_EN,
> +			aspeed->base + OPB_IRQ_MASK);
> +
> +	/* TODO: determine an appropriate value */
> +	writel(0x10, aspeed->base + OPB_RETRY_COUNTER);
> +
> +	writel(ctrl_base, aspeed->base + OPB_CTRL_BASE);
> +	writel(fsi_base, aspeed->base + OPB_FSI_BASE);
> +
> +	/* Set read data order */
> +	writel(0x0011bb1b, aspeed->base + OPB0_READ_ORDER1);
> +
> +	/* Set write data order */
> +	writel(0x0011bb1b, aspeed->base + OPB0_WRITE_ORDER1);
> +	writel(0xffaa5500, aspeed->base + OPB0_WRITE_ORDER2);
> +
> +	/*
> +	 * Select OPB0 for all operations.
> +	 * Will need to be reworked when enabling DMA or anything that uses
> +	 * OPB1.
> +	 */
> +	writel(0x1, aspeed->base + OPB0_SELECT);
> +
> +	rc = opb_readl(aspeed, ctrl_base + FSI_MVER, &raw);
> +	if (rc) {
> +		dev_err(&pdev->dev, "failed to read hub version\n");
> +		return rc;
> +	}
> +
> +	reg = be32_to_cpu(raw);
> +	links = (reg >> 8) & 0xff;
> +	dev_info(&pdev->dev, "hub version %08x (%d links)\n", reg, links);
> +
> +	aspeed->master.dev.parent = &pdev->dev;
> +	aspeed->master.dev.release = aspeed_master_release;
> +	aspeed->master.dev.of_node = of_node_get(dev_of_node(&pdev->dev));
> +
> +	aspeed->master.n_links = links;
> +	aspeed->master.read = aspeed_master_read;
> +	aspeed->master.write = aspeed_master_write;
> +	aspeed->master.send_break = aspeed_master_break;
> +	aspeed->master.term = aspeed_master_term;
> +	aspeed->master.link_enable = aspeed_master_link_enable;
> +
> +	dev_set_drvdata(&pdev->dev, aspeed);
> +
> +	aspeed_master_init(aspeed);
> +
> +	rc = fsi_master_register(&aspeed->master);
> +	if (rc)
> +		goto err_release;
> +
> +	/* At this point, fsi_master_register performs the device_initialize(),
> +	 * and holds the sole reference on master.dev. This means the device
> +	 * will be freed (via ->release) during any subsequent call to
> +	 * fsi_master_unregister.  We add our own reference to it here, so we
> +	 * can perform cleanup (in _remove()) without it being freed before
> +	 * we're ready.
> +	 */
> +	get_device(&aspeed->master.dev);
> +	return 0;
> +
> +err_release:
> +	clk_disable_unprepare(aspeed->clk);
> +	return rc;
> +}
> +
> +static int fsi_master_aspeed_remove(struct platform_device *pdev)
> +{
> +	struct fsi_master_aspeed *aspeed = platform_get_drvdata(pdev);
> +
> +	fsi_master_unregister(&aspeed->master);
> +	clk_disable_unprepare(aspeed->clk);
> +
> +	return 0;
> +}
> +
> +static const struct of_device_id fsi_master_aspeed_match[] = {
> +	{ .compatible = "aspeed,ast2600-fsi-master" },
> +	{ },
> +};
> +
> +static struct platform_driver fsi_master_aspeed_driver = {
> +	.driver = {
> +		.name		= "fsi-master-aspeed",
> +		.of_match_table	= fsi_master_aspeed_match,
> +	},
> +	.probe	= fsi_master_aspeed_probe,
> +	.remove = fsi_master_aspeed_remove,
> +};
> +
> +module_platform_driver(fsi_master_aspeed_driver);
> +MODULE_LICENSE("GPL");
> 

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