Hi Sean,
-----Original Message----- From: Sean Anderson seanga2@gmail.com Sent: 09 October 2020 17:58 To: Pragnesh Patel pragnesh.patel@openfive.com; u-boot@lists.denx.de Cc: atish.patra@wdc.com; palmerdabbelt@google.com; bmeng.cn@gmail.com; Paul Walmsley ( Sifive) paul.walmsley@sifive.com; anup.patel@wdc.com; Sagar Kadam sagar.kadam@openfive.com; rick@andestech.com; Heiko Schocher hs@denx.de Subject: Re: [PATCH 1/2] i2c: ocores: add i2c driver for OpenCores I2C controller
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On 10/9/20 1:46 AM, Pragnesh Patel wrote:
Add support for the OpenCores I2C controller IP core (See http://www.opencores.org/projects.cgi/web/i2c/overview).
This driver implementation is inspired from the Linux OpenCores I2C driver available.
Thanks to Peter Korsgaard peter@korsgaard.com for writing Linux OpenCores I2C driver.
Signed-off-by: Pragnesh Patel pragnesh.patel@sifive.com
drivers/i2c/Kconfig | 7 + drivers/i2c/Makefile | 1 + drivers/i2c/ocores_i2c.c | 638 +++++++++++++++++++++++++++++++++++++++ 3 files changed, 646 insertions(+) create mode 100644 drivers/i2c/ocores_i2c.c
diff --git a/drivers/i2c/Kconfig b/drivers/i2c/Kconfig index 8ae54e1e93..adf37177c4 100644 --- a/drivers/i2c/Kconfig +++ b/drivers/i2c/Kconfig @@ -342,6 +342,13 @@ config SYS_I2C_NEXELL have several I2C ports and all are provided, controlled by the device tree.
+config SYS_I2C_OCORES
bool "ocores I2C driver"depends on DM_I2ChelpAdd support for ocores I2C controller. For details seehttp://www.opencores.org/projects.cgi/web/i2c/overviewThis link 404s for me. https://opencores.org/projects/i2c works.
Ooops, This is copied from Linux I2C driver. I will update in v2.
config SYS_I2C_OMAP24XX bool "TI OMAP2+ I2C driver" depends on ARCH_OMAP2PLUS || ARCH_K3 diff --git a/drivers/i2c/Makefile b/drivers/i2c/Makefile index bd248cbf52..37dc8ada6d 100644 --- a/drivers/i2c/Makefile +++ b/drivers/i2c/Makefile @@ -32,6 +32,7 @@ obj-$(CONFIG_SYS_I2C_MESON) += meson_i2c.o obj-$(CONFIG_SYS_I2C_MVTWSI) += mvtwsi.o obj-$(CONFIG_SYS_I2C_MXC) += mxc_i2c.o obj-$(CONFIG_SYS_I2C_NEXELL) += nx_i2c.o +obj-$(CONFIG_SYS_I2C_OCORES) += ocores_i2c.o obj-$(CONFIG_SYS_I2C_OCTEON) += octeon_i2c.o obj-$(CONFIG_SYS_I2C_OMAP24XX) += omap24xx_i2c.o obj-$(CONFIG_SYS_I2C_RCAR_I2C) += rcar_i2c.o diff --git a/drivers/i2c/ocores_i2c.c b/drivers/i2c/ocores_i2c.c new file mode 100644 index 0000000000..b42b55625f --- /dev/null +++ b/drivers/i2c/ocores_i2c.c @@ -0,0 +1,638 @@ +// SPDX-License-Identifier: GPL-2.0+ +/*
- ocores-i2c.c: I2C bus driver for OpenCores I2C controller
- (C) Copyright Peter Korsgaard peter@korsgaard.com
- Copyright (C) 2020 SiFive, Inc.
- Pragnesh Patel pragnesh.patel@sifive.com
- Support for the GRLIB port of the controller by
- Andreas Larsson andreas@gaisler.com */
+#include <common.h> +#include <asm/io.h> +#include <clk.h> +#include <dm.h> +#include <i2c.h> +#include <linux/io.h> +#include <linux/compat.h> +#include <linux/log2.h> +#include <linux/delay.h>
+/* registers */ +#define OCI2C_PRELOW 0 +#define OCI2C_PREHIGH 1 +#define OCI2C_CONTROL 2 +#define OCI2C_DATA 3 +#define OCI2C_CMD 4 /* write only */ +#define OCI2C_STATUS 4 /* read only, same address as OCI2C_CMD */
+#define OCI2C_CTRL_IEN 0x40 +#define OCI2C_CTRL_EN 0x80
+#define OCI2C_CMD_START 0x91 +#define OCI2C_CMD_STOP 0x41 +#define OCI2C_CMD_READ 0x21 +#define OCI2C_CMD_WRITE 0x11 +#define OCI2C_CMD_READ_ACK 0x21 +#define OCI2C_CMD_READ_NACK 0x29 +#define OCI2C_CMD_IACK 0x01
+#define OCI2C_STAT_IF 0x01 +#define OCI2C_STAT_TIP 0x02 +#define OCI2C_STAT_ARBLOST 0x20 +#define OCI2C_STAT_BUSY 0x40 +#define OCI2C_STAT_NACK 0x80
+#define STATE_DONE 0 +#define STATE_START 1 +#define STATE_WRITE 2 +#define STATE_READ 3 +#define STATE_ERROR 4
+#define TYPE_OCORES 0 +#define TYPE_GRLIB 1 +#define TYPE_SIFIVE_REV0 2
+#define OCORES_FLAG_BROKEN_IRQ BIT(1) /* Broken IRQ for FU540-C000 +SoC */
+struct ocores_i2c_bus {
void __iomem *base;u32 reg_shift;u32 reg_io_width;unsigned long flags;struct i2c_msg *msg;int pos;int nmsgs;int state; /* see STATE_ */struct clk clk;int ip_clk_khz;int bus_clk_khz;void (*setreg)(struct ocores_i2c_bus *i2c, int reg, u8 value);u8 (*getreg)(struct ocores_i2c_bus *i2c, int reg); };+DECLARE_GLOBAL_DATA_PTR;
+/* Boolean attribute values */ +enum {
FALSE = 0,TRUE,+};
+static void oc_setreg_8(struct ocores_i2c_bus *i2c, int reg, u8 +value) {
writeb(value, i2c->base + (reg << i2c->reg_shift)); }+static void oc_setreg_16(struct ocores_i2c_bus *i2c, int reg, u8 +value) {
writew(value, i2c->base + (reg << i2c->reg_shift)); }+static void oc_setreg_32(struct ocores_i2c_bus *i2c, int reg, u8 +value) {
writel(value, i2c->base + (reg << i2c->reg_shift)); }+static void oc_setreg_16be(struct ocores_i2c_bus *i2c, int reg, u8 +value) {
out_be16(i2c->base + (reg << i2c->reg_shift), value); }+static void oc_setreg_32be(struct ocores_i2c_bus *i2c, int reg, u8 +value) {
out_be32(i2c->base + (reg << i2c->reg_shift), value); }+static inline u8 oc_getreg_8(struct ocores_i2c_bus *i2c, int reg) {
return readb(i2c->base + (reg << i2c->reg_shift)); }+static inline u8 oc_getreg_16(struct ocores_i2c_bus *i2c, int reg) {
return readw(i2c->base + (reg << i2c->reg_shift)); }+static inline u8 oc_getreg_32(struct ocores_i2c_bus *i2c, int reg) {
return readl(i2c->base + (reg << i2c->reg_shift)); }+static inline u8 oc_getreg_16be(struct ocores_i2c_bus *i2c, int reg) +{
return in_be16(i2c->base + (reg << i2c->reg_shift)); }+static inline u8 oc_getreg_32be(struct ocores_i2c_bus *i2c, int reg) +{
return in_be32(i2c->base + (reg << i2c->reg_shift)); }+static inline void oc_setreg(struct ocores_i2c_bus *i2c, int reg, u8 +value) {
i2c->setreg(i2c, reg, value);+}
+static inline u8 oc_getreg(struct ocores_i2c_bus *i2c, int reg) {
return i2c->getreg(i2c, reg);+}
+static inline u8 i2c_8bit_addr_from_msg(const struct i2c_msg *msg) {
return (msg->addr << 1) | (msg->flags & I2C_M_RD ? 1 : 0); }+static void ocores_process(struct ocores_i2c_bus *i2c, u8 stat) {
struct i2c_msg *msg = i2c->msg;if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR) {/* stop has been sent */oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_IACK);return;}/* error? */if (stat & OCI2C_STAT_ARBLOST) {i2c->state = STATE_ERROR;oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);return;}if (i2c->state == STATE_START || i2c->state == STATE_WRITE) {i2c->state =(msg->flags & I2C_M_RD) ? STATE_READ :- STATE_WRITE;
if (stat & OCI2C_STAT_NACK) {i2c->state = STATE_ERROR;oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);return;}} else {msg->buf[i2c->pos++] = oc_getreg(i2c, OCI2C_DATA);}/* end of msg? */if (i2c->pos == msg->len) {i2c->nmsgs--;i2c->msg++;i2c->pos = 0;msg = i2c->msg;if (i2c->nmsgs) { /* end? *//* send start? */if (!(msg->flags & I2C_M_NOSTART)) {u8 addr = i2c_8bit_addr_from_msg(msg);i2c->state = STATE_START;oc_setreg(i2c, OCI2C_DATA, addr);oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);return;}i2c->state = (msg->flags & I2C_M_RD)? STATE_READ : STATE_WRITE;} else {i2c->state = STATE_DONE;oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_STOP);return;}}if (i2c->state == STATE_READ) {oc_setreg(i2c, OCI2C_CMD, i2c->pos == (msg->len - 1) ?OCI2C_CMD_READ_NACK : OCI2C_CMD_READ_ACK);} else {oc_setreg(i2c, OCI2C_DATA, msg->buf[i2c->pos++]);oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_WRITE);}+}
+static irqreturn_t ocores_isr(int irq, void *dev_id) {
struct ocores_i2c_bus *i2c = dev_id;u8 stat = oc_getreg(i2c, OCI2C_STATUS);if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) {if ((stat & OCI2C_STAT_IF) && !(stat & OCI2C_STAT_BUSY))return IRQ_NONE;} else if (!(stat & OCI2C_STAT_IF)) {return IRQ_NONE;}ocores_process(i2c, stat);return IRQ_HANDLED;+}
+/**
- Wait until something change in a given register
- @i2c: ocores I2C device instance
- @reg: register to query
- @mask: bitmask to apply on register value
- @val: expected result
- @msec: timeout in msec
- Timeout is necessary to avoid to stay here forever when the chip
- does not answer correctly.
- Return: 0 on success, -ETIMEDOUT on timeout */ static int
+ocores_wait(struct ocores_i2c_bus *i2c,
int reg, u8 mask, u8 val,const unsigned long msec) {u32 count = 0;while (1) {u8 status = oc_getreg(i2c, reg);if ((status & mask) == val)break;udelay(1);count += 1;if (count == (1000 * msec))return -ETIMEDOUT;}return 0;+}
+/**
- Wait until is possible to process some data
- @i2c: ocores I2C device instance
- Used when the device is in polling mode (interrupts disabled).
- Return: 0 on success, -ETIMEDOUT on timeout */ static int
+ocores_poll_wait(struct ocores_i2c_bus *i2c) {
u8 mask;int err;if (i2c->state == STATE_DONE || i2c->state == STATE_ERROR) {/* transfer is over */mask = OCI2C_STAT_BUSY;} else {/* on going transfer */mask = OCI2C_STAT_TIP;/** We wait for the data to be transferred (8bit),* then we start polling on the ACK/NACK bit*/udelay((8 * 1000) / i2c->bus_clk_khz);}/** once we are here we expect to get the expected result immediately* so if after 1ms we timeout then something is broken.*/err = ocores_wait(i2c, OCI2C_STATUS, mask, 0, 1);if (err)debug("%s: STATUS timeout, bit 0x%x did not clear in 1ms\n",__func__, mask);return err;+}
+/**
- It handles an IRQ-less transfer
- @i2c: ocores I2C device instance
- Even if IRQ are disabled, the I2C OpenCore IP behavior is exactly
+the same
- (only that IRQ are not produced). This means that we can re-use
+entirely
- ocores_isr(), we just add our polling code around it.
- It can run in atomic context
- */
+static void ocores_process_polling(struct ocores_i2c_bus *i2c) {
while (1) {irqreturn_t ret;int err;err = ocores_poll_wait(i2c);if (err) {i2c->state = STATE_ERROR;break; /* timeout */}ret = ocores_isr(-1, i2c);if (ret == IRQ_NONE) {break; /* all messages have been transferred */} else {if (i2c->flags & OCORES_FLAG_BROKEN_IRQ)if (i2c->state == STATE_DONE)break;}}+}
+static int ocores_xfer_core(struct ocores_i2c_bus *i2c,
struct i2c_msg *msgs, int num, bool polling)+{
u8 ctrl;ctrl = oc_getreg(i2c, OCI2C_CONTROL);if (polling)oc_setreg(i2c, OCI2C_CONTROL, ctrl & ~OCI2C_CTRL_IEN);i2c->msg = msgs;i2c->pos = 0;i2c->nmsgs = num;i2c->state = STATE_START;oc_setreg(i2c, OCI2C_DATA, i2c_8bit_addr_from_msg(i2c->msg));oc_setreg(i2c, OCI2C_CMD, OCI2C_CMD_START);if (polling)ocores_process_polling(i2c);return (i2c->state == STATE_DONE) ? num : -EIO; }+static int ocores_i2c_xfer(struct udevice *dev, struct i2c_msg *msg, +int nmsgs) {
struct ocores_i2c_bus *bus = dev_get_priv(dev);int ret;debug("i2c_xfer: %d messages\n", nmsgs);ret = ocores_xfer_core(bus, msg, nmsgs, 1);if (ret != nmsgs) {debug("i2c_write: error sending\n");return -EREMOTEIO;}return 0;+}
+static int ocores_i2c_enable_clk(struct udevice *dev) {
struct ocores_i2c_bus *bus = dev_get_priv(dev);ulong clk_rate;int ret;ret = clk_get_by_index(dev, 0, &bus->clk);if (ret)return -EINVAL;ret = clk_enable(&bus->clk);if (ret)return ret;clk_rate = clk_get_rate(&bus->clk);if (!clk_rate)return -EINVAL;bus->ip_clk_khz = clk_rate / 1000;clk_free(&bus->clk);return 0;+}
+static int ocores_init(struct udevice *dev, struct ocores_i2c_bus +*bus) {
int prescale;int diff;u8 ctrl = oc_getreg(bus, OCI2C_CONTROL);/* make sure the device is disabled */ctrl &= ~(OCI2C_CTRL_EN | OCI2C_CTRL_IEN);oc_setreg(bus, OCI2C_CONTROL, ctrl);prescale = (bus->ip_clk_khz / (5 * bus->bus_clk_khz)) - 1;prescale = clamp(prescale, 0, 0xffff);diff = bus->ip_clk_khz / (5 * (prescale + 1)) - bus->bus_clk_khz;if (abs(diff) > bus->bus_clk_khz / 10) {debug("Unsupported clock settings: core: %d KHz, bus: %d KHz\n",bus->ip_clk_khz, bus->bus_clk_khz);return -EINVAL;}oc_setreg(bus, OCI2C_PRELOW, prescale & 0xff);oc_setreg(bus, OCI2C_PREHIGH, prescale >> 8);/* Init the device */oc_setreg(bus, OCI2C_CMD, OCI2C_CMD_IACK);oc_setreg(bus, OCI2C_CONTROL, ctrl | OCI2C_CTRL_EN);return 0;+}
+/*
- Read and write functions for the GRLIB port of the controller.
+Registers are
- 32-bit big endian and the PRELOW and PREHIGH registers are merged
+into one
- register. The subsequent registers have their offsets decreased accordingly.
- */
+static u8 oc_getreg_grlib(struct ocores_i2c_bus *i2c, int reg) {
u32 rd;int rreg = reg;if (reg != OCI2C_PRELOW)rreg--;rd = in_be32(i2c->base + (rreg << i2c->reg_shift));if (reg == OCI2C_PREHIGH)return (u8)(rd >> 8);elsereturn (u8)rd;+}
+static void oc_setreg_grlib(struct ocores_i2c_bus *i2c, int reg, u8 +value) {
u32 curr, wr;int rreg = reg;if (reg != OCI2C_PRELOW)rreg--;if (reg == OCI2C_PRELOW || reg == OCI2C_PREHIGH) {curr = in_be32(i2c->base + (rreg << i2c->reg_shift));if (reg == OCI2C_PRELOW)wr = (curr & 0xff00) | value;elsewr = (((u32)value) << 8) | (curr & 0xff);} else {wr = value;}out_be32(i2c->base + (rreg << i2c->reg_shift), wr); }+static int ocores_i2c_set_bus_speed(struct udevice *dev, unsigned int +speed) {
int prescale;int diff;struct ocores_i2c_bus *bus = dev_get_priv(dev);/* speed in Khz */speed = speed / 1000;prescale = (bus->ip_clk_khz / (5 * speed)) - 1;prescale = clamp(prescale, 0, 0xffff);diff = bus->ip_clk_khz / (5 * (prescale + 1)) - speed;if (abs(diff) > speed / 10) {debug("Unsupported clock settings: core: %d KHz, bus: %d KHz\n",bus->ip_clk_khz, speed);return -EINVAL;}oc_setreg(bus, OCI2C_PRELOW, prescale & 0xff);oc_setreg(bus, OCI2C_PREHIGH, prescale >> 8);bus->bus_clk_khz = speed;return 0;+}
+int ocores_i2c_get_bus_speed(struct udevice *dev) {
struct ocores_i2c_bus *bus = dev_get_priv(dev);return (bus->bus_clk_khz * 1000); }+static const struct dm_i2c_ops ocores_i2c_ops = {
.xfer = ocores_i2c_xfer,.set_bus_speed = ocores_i2c_set_bus_speed,.get_bus_speed = ocores_i2c_get_bus_speed, };+static int ocores_i2c_probe(struct udevice *dev) {
struct ocores_i2c_bus *bus = dev_get_priv(dev);bool clock_frequency_present;u32 val;u32 clock_frequency_khz;int ret;bus->base = (void __iomem *)devfdt_get_addr(dev);if (dev_read_u32(dev, "reg-shift", &bus->reg_shift)) {/* no 'reg-shift', check for deprecated 'regstep' */ret = dev_read_u32(dev, "regstep", &val);if (ret) {dev_err(dev,"missing both reg-shift and regstep property: %d\n", ret);return -EINVAL;} else {bus->reg_shift = ilog2(val);dev_warn(dev,"regstep property deprecated, use reg-shift\n");}}if (dev_read_u32(dev, "clock-frequency", &val)) {bus->bus_clk_khz = 100;clock_frequency_present = FALSE;} else {bus->bus_clk_khz = val / 1000;clock_frequency_khz = val / 1000;clock_frequency_present = TRUE;}ret = ocores_i2c_enable_clk(dev);if (ret)return ret;if (bus->ip_clk_khz == 0) {if (dev_read_u32(dev, "opencores,ip-clock-frequency", &val)) {if (!clock_frequency_present) {dev_err(dev,"Missing required parameter 'opencores,ip-clock-frequency'\n");
clk_disable(&bus->clk);return -ENODEV;}bus->ip_clk_khz = clock_frequency_khz;dev_warn(dev,"Deprecated usage of the- 'clock-frequency' property, please update to
- 'opencores,ip-clock-frequency'\n");
Do we need to maintain backwards-compatibility here? I checked the original commit 3a33a85401ec ("i2c: ocores: fix clock-frequency binding usage"), and it seems that this property has been deprecated since 2015.
Yes, we need to support this backward compatibility here.
Linux I2C driver still used this "clock-frequency" property if "opencores,ip-clock-frequency" is not provided, So U-Boot I2C driver also need to support the same.
} else {bus->ip_clk_khz = val / 1000;if (clock_frequency_present)bus->bus_clk_khz = clock_frequency_khz;}}bus->reg_io_width = dev_read_u32_default(dev, "reg-io-width",- 1);
if (dev_get_driver_data(dev) == TYPE_GRLIB) {debug("GRLIB variant of i2c-ocores\n");bus->setreg = oc_setreg_grlib;bus->getreg = oc_getreg_grlib;}if (!bus->setreg || !bus->getreg) {bool be = (cpu_to_be32(0x12345678) == 0x12345678);switch (bus->reg_io_width) {case 1:bus->setreg = oc_setreg_8;bus->getreg = oc_getreg_8;break;case 2:bus->setreg = be ? oc_setreg_16be : oc_setreg_16;bus->getreg = be ? oc_getreg_16be : oc_getreg_16;break;case 4:bus->setreg = be ? oc_setreg_32be : oc_setreg_32;bus->getreg = be ? oc_getreg_32be : oc_getreg_32;break;default:debug("Unsupported I/O width (%d)\n",bus->reg_io_width);ret = -EINVAL;goto err_clk;}}/** Set OCORES_FLAG_BROKEN_IRQ to enable workaround for* FU540-C000 SoC in polling mode.* Since the SoC does have interrupt it's dt has the interrupt* defined but it should be bypassed in driver as this SoC has* a broken IRQ, hence update the master_xfer to use polling* transfers.*/if (dev_get_driver_data(dev) == TYPE_SIFIVE_REV0)bus->flags |= OCORES_FLAG_BROKEN_IRQ;ret = ocores_init(dev, bus);if (ret)goto err_clk;return 0;+err_clk:
clk_disable(&bus->clk);return ret;+}
+static const struct udevice_id ocores_i2c_ids[] = { { .compatible = +"opencores,i2c-ocores", .data = TYPE_OCORES }, { .compatible = +"aeroflexgaisler,i2cmst", .data = TYPE_GRLIB }, { .compatible = +"sifive,fu540-c000-i2c", .data = TYPE_SIFIVE_REV0 }, { .compatible = +"sifive,i2c0", .data = TYPE_SIFIVE_REV0 }, };
+U_BOOT_DRIVER(i2c_ocores) = {
.name = "i2c_ocores",.id = UCLASS_I2C,.of_match = ocores_i2c_ids,.probe = ocores_i2c_probe,.priv_auto_alloc_size = sizeof(struct ocores_i2c_bus),.ops = &ocores_i2c_ops,+};