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Date: Wed, 11 Apr 2018 19:03:57 -0700
From: Jae Hyun Yoo <jae.hyun.yoo@...ux.intel.com>
To: Joel Stanley <joel@....id.au>, Ryan Chen <ryan_chen@...eedtech.com>
Cc: Alan Cox <alan@...ux.intel.com>, Andrew Jeffery <andrew@...id.au>,
Andrew Lunn <andrew@...n.ch>,
Andy Shevchenko <andriy.shevchenko@...el.com>,
Arnd Bergmann <arnd@...db.de>,
Benjamin Herrenschmidt <benh@...nel.crashing.org>,
Fengguang Wu <fengguang.wu@...el.com>,
Greg KH <gregkh@...uxfoundation.org>,
Guenter Roeck <linux@...ck-us.net>,
Haiyue Wang <haiyue.wang@...ux.intel.com>,
James Feist <james.feist@...ux.intel.com>,
Jason M Biils <jason.m.bills@...ux.intel.com>,
Jean Delvare <jdelvare@...e.com>,
Julia Cartwright <juliac@....teric.us>,
Miguel Ojeda <miguel.ojeda.sandonis@...il.com>,
Milton Miller II <miltonm@...ibm.com>,
Pavel Machek <pavel@....cz>,
Randy Dunlap <rdunlap@...radead.org>,
Stef van Os <stef.van.os@...drive-technologies.com>,
Sumeet R Pawnikar <sumeet.r.pawnikar@...el.com>,
Vernon Mauery <vernon.mauery@...ux.intel.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-doc@...r.kernel.org, devicetree <devicetree@...r.kernel.org>,
linux-hwmon@...r.kernel.org,
Linux ARM <linux-arm-kernel@...ts.infradead.org>,
OpenBMC Maillist <openbmc@...ts.ozlabs.org>
Subject: Re: [PATCH v3 06/10] drivers/peci: Add a PECI adapter driver for
Aspeed AST24xx/AST25xx
Hello Joel,
Thanks for sharing your time. Please see my answers inline.
On 4/11/2018 4:51 AM, Joel Stanley wrote:
> Hello Jae,
>
> On 11 April 2018 at 04:02, Jae Hyun Yoo <jae.hyun.yoo@...ux.intel.com> wrote:
>> This commit adds PECI adapter driver implementation for Aspeed
>> AST24xx/AST25xx.
>
> The driver is looking good!
>
> It looks like you've done some kind of review that we weren't allowed
> to see, which is a double edged sword - I might be asking about things
> that you've already spoken about with someone else.
>
> I'm only just learning about PECI, but I do have some general comments below.
>
Yes, it took a hidden review process between v2 and v3. I know it's an
unusual process but it was requested. Hopefully, change logs in cover
letter could roughly provide the details. Thanks for your comments.
>> ---
>> drivers/peci/Kconfig | 28 +++
>> drivers/peci/Makefile | 3 +
>> drivers/peci/peci-aspeed.c | 504 +++++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 535 insertions(+)
>> create mode 100644 drivers/peci/peci-aspeed.c
>>
>> diff --git a/drivers/peci/Kconfig b/drivers/peci/Kconfig
>> index 1fbc13f9e6c2..0e33420365de 100644
>> --- a/drivers/peci/Kconfig
>> +++ b/drivers/peci/Kconfig
>> @@ -14,4 +14,32 @@ config PECI
>> processors and chipset components to external monitoring or control
>> devices.
>>
>> + If you want PECI support, you should say Y here and also to the
>> + specific driver for your bus adapter(s) below.
>> +
>> +if PECI
>> +
>> +#
>> +# PECI hardware bus configuration
>> +#
>> +
>> +menu "PECI Hardware Bus support"
>> +
>> +config PECI_ASPEED
>> + tristate "Aspeed AST24xx/AST25xx PECI support"
>
> I think just saying ASPEED PECI support is enough. That way if the
> next ASPEED SoC happens to have PECI we don't need to update all of
> the help text :)
>
Agreed. I'll change the description.
>> + select REGMAP_MMIO
>> + depends on OF
>> + depends on ARCH_ASPEED || COMPILE_TEST
>> + help
>> + Say Y here if you want support for the Platform Environment Control
>> + Interface (PECI) bus adapter driver on the Aspeed AST24XX and AST25XX
>> + SoCs.
>> +
>> + This support is also available as a module. If so, the module
>> + will be called peci-aspeed.
>> +
>> +endmenu
>> +
>> +endif # PECI
>> +
>> endmenu
>> diff --git a/drivers/peci/Makefile b/drivers/peci/Makefile
>> index 9e8615e0d3ff..886285e69765 100644
>> --- a/drivers/peci/Makefile
>> +++ b/drivers/peci/Makefile
>> @@ -4,3 +4,6 @@
>>
>> # Core functionality
>> obj-$(CONFIG_PECI) += peci-core.o
>> +
>> +# Hardware specific bus drivers
>> +obj-$(CONFIG_PECI_ASPEED) += peci-aspeed.o
>> diff --git a/drivers/peci/peci-aspeed.c b/drivers/peci/peci-aspeed.c
>> new file mode 100644
>> index 000000000000..be2a1f327eb1
>> --- /dev/null
>> +++ b/drivers/peci/peci-aspeed.c
>> @@ -0,0 +1,504 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +// Copyright (C) 2012-2017 ASPEED Technology Inc.
>> +// Copyright (c) 2018 Intel Corporation
>> +
>> +#include <linux/clk.h>
>> +#include <linux/delay.h>
>> +#include <linux/interrupt.h>
>> +#include <linux/jiffies.h>
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/peci.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/regmap.h>
>> +
>> +#define DUMP_DEBUG 0
>> +
>> +/* Aspeed PECI Registers */
>> +#define AST_PECI_CTRL 0x00
>
> Nit: we use ASPEED instead of AST in the upstream kernel to distingush
> from the aspeed sdk drivers. If you feel strongly about this then I
> won't insist you change.
>
Okay then, better change it now than later. Will change all defines.
>> +#define AST_PECI_TIMING 0x04
>> +#define AST_PECI_CMD 0x08
>> +#define AST_PECI_CMD_CTRL 0x0c
>> +#define AST_PECI_EXP_FCS 0x10
>> +#define AST_PECI_CAP_FCS 0x14
>> +#define AST_PECI_INT_CTRL 0x18
>> +#define AST_PECI_INT_STS 0x1c
>> +#define AST_PECI_W_DATA0 0x20
>> +#define AST_PECI_W_DATA1 0x24
>> +#define AST_PECI_W_DATA2 0x28
>> +#define AST_PECI_W_DATA3 0x2c
>> +#define AST_PECI_R_DATA0 0x30
>> +#define AST_PECI_R_DATA1 0x34
>> +#define AST_PECI_R_DATA2 0x38
>> +#define AST_PECI_R_DATA3 0x3c
>> +#define AST_PECI_W_DATA4 0x40
>> +#define AST_PECI_W_DATA5 0x44
>> +#define AST_PECI_W_DATA6 0x48
>> +#define AST_PECI_W_DATA7 0x4c
>> +#define AST_PECI_R_DATA4 0x50
>> +#define AST_PECI_R_DATA5 0x54
>> +#define AST_PECI_R_DATA6 0x58
>> +#define AST_PECI_R_DATA7 0x5c
>> +
>> +/* AST_PECI_CTRL - 0x00 : Control Register */
>> +#define PECI_CTRL_SAMPLING_MASK GENMASK(19, 16)
>> +#define PECI_CTRL_SAMPLING(x) (((x) << 16) & PECI_CTRL_SAMPLING_MASK)
>> +#define PECI_CTRL_SAMPLING_GET(x) (((x) & PECI_CTRL_SAMPLING_MASK) >> 16)
>> +#define PECI_CTRL_READ_MODE_MASK GENMASK(13, 12)
>> +#define PECI_CTRL_READ_MODE(x) (((x) << 12) & PECI_CTRL_READ_MODE_MASK)
>> +#define PECI_CTRL_READ_MODE_GET(x) (((x) & PECI_CTRL_READ_MODE_MASK) >> 12)
>> +#define PECI_CTRL_READ_MODE_COUNT BIT(12)
>> +#define PECI_CTRL_READ_MODE_DBG BIT(13)
>> +#define PECI_CTRL_CLK_SOURCE_MASK BIT(11)
>> +#define PECI_CTRL_CLK_SOURCE(x) (((x) << 11) & PECI_CTRL_CLK_SOURCE_MASK)
>> +#define PECI_CTRL_CLK_SOURCE_GET(x) (((x) & PECI_CTRL_CLK_SOURCE_MASK) >> 11)
>> +#define PECI_CTRL_CLK_DIV_MASK GENMASK(10, 8)
>> +#define PECI_CTRL_CLK_DIV(x) (((x) << 8) & PECI_CTRL_CLK_DIV_MASK)
>> +#define PECI_CTRL_CLK_DIV_GET(x) (((x) & PECI_CTRL_CLK_DIV_MASK) >> 8)
>> +#define PECI_CTRL_INVERT_OUT BIT(7)
>> +#define PECI_CTRL_INVERT_IN BIT(6)
>> +#define PECI_CTRL_BUS_CONTENT_EN BIT(5)
>> +#define PECI_CTRL_PECI_EN BIT(4)
>> +#define PECI_CTRL_PECI_CLK_EN BIT(0)
>
> I know these come from the ASPEED sdk driver. Do we need them all?
>
It doesn't use all but better keep for bug fix or improvement use, I think.
>> +
>> +/* AST_PECI_TIMING - 0x04 : Timing Negotiation Register */
>> +#define PECI_TIMING_MESSAGE_MASK GENMASK(15, 8)
>> +#define PECI_TIMING_MESSAGE(x) (((x) << 8) & PECI_TIMING_MESSAGE_MASK)
>> +#define PECI_TIMING_MESSAGE_GET(x) (((x) & PECI_TIMING_MESSAGE_MASK) >> 8)
>> +#define PECI_TIMING_ADDRESS_MASK GENMASK(7, 0)
>> +#define PECI_TIMING_ADDRESS(x) ((x) & PECI_TIMING_ADDRESS_MASK)
>> +#define PECI_TIMING_ADDRESS_GET(x) ((x) & PECI_TIMING_ADDRESS_MASK)
>> +
>> +/* AST_PECI_CMD - 0x08 : Command Register */
>> +#define PECI_CMD_PIN_MON BIT(31)
>> +#define PECI_CMD_STS_MASK GENMASK(27, 24)
>> +#define PECI_CMD_STS_GET(x) (((x) & PECI_CMD_STS_MASK) >> 24)
>> +#define PECI_CMD_FIRE BIT(0)
>> +
>> +/* AST_PECI_LEN - 0x0C : Read/Write Length Register */
>> +#define PECI_AW_FCS_EN BIT(31)
>> +#define PECI_READ_LEN_MASK GENMASK(23, 16)
>> +#define PECI_READ_LEN(x) (((x) << 16) & PECI_READ_LEN_MASK)
>> +#define PECI_WRITE_LEN_MASK GENMASK(15, 8)
>> +#define PECI_WRITE_LEN(x) (((x) << 8) & PECI_WRITE_LEN_MASK)
>> +#define PECI_TAGET_ADDR_MASK GENMASK(7, 0)
>> +#define PECI_TAGET_ADDR(x) ((x) & PECI_TAGET_ADDR_MASK)
>> +
>> +/* AST_PECI_EXP_FCS - 0x10 : Expected FCS Data Register */
>> +#define PECI_EXPECT_READ_FCS_MASK GENMASK(23, 16)
>> +#define PECI_EXPECT_READ_FCS_GET(x) (((x) & PECI_EXPECT_READ_FCS_MASK) >> 16)
>> +#define PECI_EXPECT_AW_FCS_AUTO_MASK GENMASK(15, 8)
>> +#define PECI_EXPECT_AW_FCS_AUTO_GET(x) (((x) & PECI_EXPECT_AW_FCS_AUTO_MASK) \
>> + >> 8)
>> +#define PECI_EXPECT_WRITE_FCS_MASK GENMASK(7, 0)
>> +#define PECI_EXPECT_WRITE_FCS_GET(x) ((x) & PECI_EXPECT_WRITE_FCS_MASK)
>> +
>> +/* AST_PECI_CAP_FCS - 0x14 : Captured FCS Data Register */
>> +#define PECI_CAPTURE_READ_FCS_MASK GENMASK(23, 16)
>> +#define PECI_CAPTURE_READ_FCS_GET(x) (((x) & PECI_CAPTURE_READ_FCS_MASK) >> 16)
>> +#define PECI_CAPTURE_WRITE_FCS_MASK GENMASK(7, 0)
>> +#define PECI_CAPTURE_WRITE_FCS_GET(x) ((x) & PECI_CAPTURE_WRITE_FCS_MASK)
>> +
>> +/* AST_PECI_INT_CTRL/STS - 0x18/0x1c : Interrupt Register */
>> +#define PECI_INT_TIMING_RESULT_MASK GENMASK(31, 30)
>> +#define PECI_INT_TIMEOUT BIT(4)
>> +#define PECI_INT_CONNECT BIT(3)
>> +#define PECI_INT_W_FCS_BAD BIT(2)
>> +#define PECI_INT_W_FCS_ABORT BIT(1)
>> +#define PECI_INT_CMD_DONE BIT(0)
>> +
>> +struct aspeed_peci {
>> + struct peci_adapter adaper;
>> + struct device *dev;
>> + struct regmap *regmap;
>> + int irq;
>> + struct completion xfer_complete;
>> + u32 status;
>> + u32 cmd_timeout_ms;
>> +};
>> +
>> +#define PECI_INT_MASK (PECI_INT_TIMEOUT | PECI_INT_CONNECT | \
>> + PECI_INT_W_FCS_BAD | PECI_INT_W_FCS_ABORT | \
>> + PECI_INT_CMD_DONE)
>> +
>> +#define PECI_IDLE_CHECK_TIMEOUT_MS 50
>> +#define PECI_IDLE_CHECK_INTERVAL_MS 10
>> +
>> +#define PECI_RD_SAMPLING_POINT_DEFAULT 8
>> +#define PECI_RD_SAMPLING_POINT_MAX 15
>> +#define PECI_CLK_DIV_DEFAULT 0
>> +#define PECI_CLK_DIV_MAX 7
>> +#define PECI_MSG_TIMING_NEGO_DEFAULT 1
>> +#define PECI_MSG_TIMING_NEGO_MAX 255
>> +#define PECI_ADDR_TIMING_NEGO_DEFAULT 1
>> +#define PECI_ADDR_TIMING_NEGO_MAX 255
>> +#define PECI_CMD_TIMEOUT_MS_DEFAULT 1000
>> +#define PECI_CMD_TIMEOUT_MS_MAX 60000
>> +
>> +static int aspeed_peci_xfer_native(struct aspeed_peci *priv,
>> + struct peci_xfer_msg *msg)
>> +{
>> + long err, timeout = msecs_to_jiffies(priv->cmd_timeout_ms);
>> + u32 peci_head, peci_state, rx_data, cmd_sts;
>> + ktime_t start, end;
>> + s64 elapsed_ms;
>> + int i, rc = 0;
>> + uint reg;
>> +
>> + start = ktime_get();
>> +
>> + /* Check command sts and bus idle state */
>> + while (!regmap_read(priv->regmap, AST_PECI_CMD, &cmd_sts) &&
>> + (cmd_sts & (PECI_CMD_STS_MASK | PECI_CMD_PIN_MON))) {
>> + end = ktime_get();
>> + elapsed_ms = ktime_to_ms(ktime_sub(end, start));
>> + if (elapsed_ms >= PECI_IDLE_CHECK_TIMEOUT_MS) {
>> + dev_dbg(priv->dev, "Timeout waiting for idle state!\n");
>> + return -ETIMEDOUT;
>> + }
>> +
>> + usleep_range(PECI_IDLE_CHECK_INTERVAL_MS * 1000,
>> + (PECI_IDLE_CHECK_INTERVAL_MS * 1000) + 1000);
>> + };
>
> Could the above use regmap_read_poll_timeout instead?
>
Yes, that would be better. I'll rewrite it.
>> +
>> + reinit_completion(&priv->xfer_complete);
>> +
>> + peci_head = PECI_TAGET_ADDR(msg->addr) |
>> + PECI_WRITE_LEN(msg->tx_len) |
>> + PECI_READ_LEN(msg->rx_len);
>> +
>> + rc = regmap_write(priv->regmap, AST_PECI_CMD_CTRL, peci_head);
>> + if (rc)
>> + return rc;
>> +
>> + for (i = 0; i < msg->tx_len; i += 4) {
>> + reg = i < 16 ? AST_PECI_W_DATA0 + i % 16 :
>> + AST_PECI_W_DATA4 + i % 16;
>> + rc = regmap_write(priv->regmap, reg,
>> + (msg->tx_buf[i + 3] << 24) |
>> + (msg->tx_buf[i + 2] << 16) |
>> + (msg->tx_buf[i + 1] << 8) |
>> + msg->tx_buf[i + 0]);
>
> That looks like an endian swap. Can we do something like this?
>
> regmap_write(map, reg, cpu_to_be32p((void *)msg->tx_buff))
>
Yes, it could be simplified like you pointed out. Will change it.
>> + if (rc)
>> + return rc;
>> + }
>> +
>> + dev_dbg(priv->dev, "HEAD : 0x%08x\n", peci_head);
>> +#if DUMP_DEBUG
>
> Having #defines is frowned upon. I think print_hex_dump_debug will do
> what you want here.
>
Got it. I'll replace it with print_hex_dump_debug() after removing the
define.
>> + print_hex_dump(KERN_DEBUG, "TX : ", DUMP_PREFIX_NONE, 16, 1,
>> + msg->tx_buf, msg->tx_len, true);
>> +#endif
>> +
>> + rc = regmap_write(priv->regmap, AST_PECI_CMD, PECI_CMD_FIRE);
>> + if (rc)
>> + return rc;
>> +
>> + err = wait_for_completion_interruptible_timeout(&priv->xfer_complete,
>> + timeout);
>> +
>> + dev_dbg(priv->dev, "INT_STS : 0x%08x\n", priv->status);
>> + if (!regmap_read(priv->regmap, AST_PECI_CMD, &peci_state))
>> + dev_dbg(priv->dev, "PECI_STATE : 0x%lx\n",
>> + PECI_CMD_STS_GET(peci_state));
>> + else
>> + dev_dbg(priv->dev, "PECI_STATE : read error\n");
>> +
>> + rc = regmap_write(priv->regmap, AST_PECI_CMD, 0);
>> + if (rc)
>> + return rc;
>> +
>> + if (err <= 0 || !(priv->status & PECI_INT_CMD_DONE)) {
>> + if (err < 0) { /* -ERESTARTSYS */
>> + return (int)err;
>> + } else if (err == 0) {
>> + dev_dbg(priv->dev, "Timeout waiting for a response!\n");
>> + return -ETIMEDOUT;
>> + }
>> +
>> + dev_dbg(priv->dev, "No valid response!\n");
>> + return -EIO;
>> + }
>> +
>> + for (i = 0; i < msg->rx_len; i++) {
>> + u8 byte_offset = i % 4;
>> +
>> + if (byte_offset == 0) {
>> + reg = i < 16 ? AST_PECI_R_DATA0 + i % 16 :
>> + AST_PECI_R_DATA4 + i % 16;
>
> I find this hard to read. Use a few more lines to make it clear what
> your code is doing.
>
> Actually, the entire for loop is cryptic. I understand what it's doing
> now. Can you rework it to make it more readable? You follow a similar
> pattern above in the write case.
>
Intention was that make it run just amount up to the rx_len but it's not
efficient. I'll rewrite it like you suggested.
>> + rc = regmap_read(priv->regmap, reg, &rx_data);
>> + if (rc)
>> + return rc;
>> + }
>> +
>> + msg->rx_buf[i] = (u8)(rx_data >> (byte_offset << 3))
>> + }
>> +
>> +#if DUMP_DEBUG
>> + print_hex_dump(KERN_DEBUG, "RX : ", DUMP_PREFIX_NONE, 16, 1,
>> + msg->rx_buf, msg->rx_len, true);
>> +#endif
>> + if (!regmap_read(priv->regmap, AST_PECI_CMD, &peci_state))
>> + dev_dbg(priv->dev, "PECI_STATE : 0x%lx\n",
>> + PECI_CMD_STS_GET(peci_state));
>> + else
>> + dev_dbg(priv->dev, "PECI_STATE : read error\n");
>
> Given the regmap_read is always going to be a memory read on the
> aspeed, I can't think of a situation where the read will fail.
>
> On that note, is there a reason you are using regmap and not just
> accessing the hardware directly? regmap imposes a number of pointer
> lookups and tests each time you do a read or write.
>
No specific reason. regmap makes some overhead as you mentioned but it
also provides some advantages on access simplification, endianness
handling and register dump at run time. I'd not insist using of regmap
if you prefer using of raw readl and writel. Do you?
>> + dev_dbg(priv->dev, "------------------------\n");
>> +
>> + return rc;
>> +}
>> +
>> +static irqreturn_t aspeed_peci_irq_handler(int irq, void *arg)
>> +{
>> + struct aspeed_peci *priv = arg;
>> + u32 status_ack = 0;
>> +
>> + if (regmap_read(priv->regmap, AST_PECI_INT_STS, &priv->status))
>> + return IRQ_NONE;
>
> Again, a memory mapped read won't fail. How about we check that the
> regmap is working once in your _probe() function, and assume it will
> continue working from there (or remove the regmap abstraction all
> together).
>
You are right. I'll keep this checking only in _probe() function and
remove all redundant error checking codes on memory mapped IO.
>> +
>> + /* Be noted that multiple interrupt bits can be set at the same time */
>> + if (priv->status & PECI_INT_TIMEOUT) {
>> + dev_dbg(priv->dev, "PECI_INT_TIMEOUT\n");
>> + status_ack |= PECI_INT_TIMEOUT;
>> + }
>> +
>> + if (priv->status & PECI_INT_CONNECT) {
>> + dev_dbg(priv->dev, "PECI_INT_CONNECT\n");
>> + status_ack |= PECI_INT_CONNECT;
>> + }
>> +
>> + if (priv->status & PECI_INT_W_FCS_BAD) {
>> + dev_dbg(priv->dev, "PECI_INT_W_FCS_BAD\n");
>> + status_ack |= PECI_INT_W_FCS_BAD;
>> + }
>> +
>> + if (priv->status & PECI_INT_W_FCS_ABORT) {
>> + dev_dbg(priv->dev, "PECI_INT_W_FCS_ABORT\n");
>> + status_ack |= PECI_INT_W_FCS_ABORT;
>> + }
>
> All of this code is for debugging only. Do you want to put it behind
> some kind of conditional?
>
This code makes changes on the status_ack variable to write back ack bit
on each interrupt.
>> +
>> + /**
>> + * All commands should be ended up with a PECI_INT_CMD_DONE bit set
>> + * even in an error case.
>> + */
>> + if (priv->status & PECI_INT_CMD_DONE) {
>> + dev_dbg(priv->dev, "PECI_INT_CMD_DONE\n");
>> + status_ack |= PECI_INT_CMD_DONE;
>> + complete(&priv->xfer_complete);
>> + }
>> +
>> + if (regmap_write(priv->regmap, AST_PECI_INT_STS, status_ack))
>> + return IRQ_NONE;
>> +
>> + return IRQ_HANDLED;
>> +}
>> +
>> +static int aspeed_peci_init_ctrl(struct aspeed_peci *priv)
>> +{
>> + u32 msg_timing_nego, addr_timing_nego, rd_sampling_point;
>> + u32 clk_freq, clk_divisor, clk_div_val = 0;
>> + struct clk *clkin;
>> + int ret;
>> +
>> + clkin = devm_clk_get(priv->dev, NULL);
>> + if (IS_ERR(clkin)) {
>> + dev_err(priv->dev, "Failed to get clk source.\n");
>> + return PTR_ERR(clkin);
>> + }
>> +
>> + ret = of_property_read_u32(priv->dev->of_node, "clock-frequency",
>> + &clk_freq);
>> + if (ret < 0) {
>> + dev_err(priv->dev,
>> + "Could not read clock-frequency property.\n");
>> + return ret;
>> + }
>> +
>> + clk_divisor = clk_get_rate(clkin) / clk_freq;
>> + devm_clk_put(priv->dev, clkin);
>> +
>> + while ((clk_divisor >> 1) && (clk_div_val < PECI_CLK_DIV_MAX))
>> + clk_div_val++;
>
> We have a framework for doing clocks in the kernel. Would it make
> sense to write a driver for this clock and add it to
> drivers/clk/clk-aspeed.c?
>
Unlike other HW module, PECI uses the 24MHz external clock as its clock
source. Should it use clk-aspeed.c in this case?
>> +
>> + ret = of_property_read_u32(priv->dev->of_node, "msg-timing-nego",
>> + &msg_timing_nego);
>> + if (ret || msg_timing_nego > PECI_MSG_TIMING_NEGO_MAX) {
>> + dev_warn(priv->dev,
>> + "Invalid msg-timing-nego : %u, Use default : %u\n",
>> + msg_timing_nego, PECI_MSG_TIMING_NEGO_DEFAULT);
>
> The property is optional so I suggest we don't print a message if it's
> not present. We certainly don't want to print a message saying
> "invalid".
>
> The same comment applies to the other optional properties below.
>
Agreed. I'll make it print out the message only when ret == 0 and
msg_timing_nego > PECI_MSG_TIMING_NEGO_MAX.
>> + msg_timing_nego = PECI_MSG_TIMING_NEGO_DEFAULT;
>> + }
>> +
>> + ret = of_property_read_u32(priv->dev->of_node, "addr-timing-nego",
>> + &addr_timing_nego);
>> + if (ret || addr_timing_nego > PECI_ADDR_TIMING_NEGO_MAX) {
>> + dev_warn(priv->dev,
>> + "Invalid addr-timing-nego : %u, Use default : %u\n",
>> + addr_timing_nego, PECI_ADDR_TIMING_NEGO_DEFAULT);
>> + addr_timing_nego = PECI_ADDR_TIMING_NEGO_DEFAULT;
>> + }
>> +
>> + ret = of_property_read_u32(priv->dev->of_node, "rd-sampling-point",
>> + &rd_sampling_point);
>> + if (ret || rd_sampling_point > PECI_RD_SAMPLING_POINT_MAX) {
>> + dev_warn(priv->dev,
>> + "Invalid rd-sampling-point : %u. Use default : %u\n",
>> + rd_sampling_point,
>> + PECI_RD_SAMPLING_POINT_DEFAULT);
>> + rd_sampling_point = PECI_RD_SAMPLING_POINT_DEFAULT;
>> + }
>> +
>> + ret = of_property_read_u32(priv->dev->of_node, "cmd-timeout-ms",
>> + &priv->cmd_timeout_ms);
>> + if (ret || priv->cmd_timeout_ms > PECI_CMD_TIMEOUT_MS_MAX ||
>> + priv->cmd_timeout_ms == 0) {
>> + dev_warn(priv->dev,
>> + "Invalid cmd-timeout-ms : %u. Use default : %u\n",
>> + priv->cmd_timeout_ms,
>> + PECI_CMD_TIMEOUT_MS_DEFAULT);
>> + priv->cmd_timeout_ms = PECI_CMD_TIMEOUT_MS_DEFAULT;
>> + }
>> +
>> + ret = regmap_write(priv->regmap, AST_PECI_CTRL,
>> + PECI_CTRL_CLK_DIV(PECI_CLK_DIV_DEFAULT) |
>> + PECI_CTRL_PECI_CLK_EN);
>> + if (ret)
>> + return ret;
>> +
>> + usleep_range(1000, 5000);
>
> Can we probe in parallel? If not, putting a sleep in the _probe will
> hold up the rest of drivers from being able to do anything, and hold
> up boot.
>
> If you decide that you do need to probe here, please add a comment.
> (This is the wait for the clock to be stable?)
>
I'll test it again and will remove it if it is not necessary.
>> +
>> + /**
>> + * Timing negotiation period setting.
>> + * The unit of the programmed value is 4 times of PECI clock period.
>> + */
>> + ret = regmap_write(priv->regmap, AST_PECI_TIMING,
>> + PECI_TIMING_MESSAGE(msg_timing_nego) |
>> + PECI_TIMING_ADDRESS(addr_timing_nego));
>> + if (ret)
>> + return ret;
>> +
>> + /* Clear interrupts */
>> + ret = regmap_write(priv->regmap, AST_PECI_INT_STS, PECI_INT_MASK);
>> + if (ret)
>> + return ret;
>> +
>> + /* Enable interrupts */
>> + ret = regmap_write(priv->regmap, AST_PECI_INT_CTRL, PECI_INT_MASK);
>> + if (ret)
>> + return ret;
>> +
>> + /* Read sampling point and clock speed setting */
>> + ret = regmap_write(priv->regmap, AST_PECI_CTRL,
>> + PECI_CTRL_SAMPLING(rd_sampling_point) |
>> + PECI_CTRL_CLK_DIV(clk_div_val) |
>> + PECI_CTRL_PECI_EN | PECI_CTRL_PECI_CLK_EN);
>> + if (ret)
>> + return ret;
>> +
>> + return 0;
>> +}
>> +
>> +static const struct regmap_config aspeed_peci_regmap_config = {
>> + .reg_bits = 32,
>> + .val_bits = 32,
>> + .reg_stride = 4,
>> + .max_register = AST_PECI_R_DATA7,
>> + .val_format_endian = REGMAP_ENDIAN_LITTLE,
>> + .fast_io = true,
>> +};
>> +
>> +static int aspeed_peci_xfer(struct peci_adapter *adaper,
>> + struct peci_xfer_msg *msg)
>> +{
>> + struct aspeed_peci *priv = peci_get_adapdata(adaper);
>> +
>> + return aspeed_peci_xfer_native(priv, msg);
>> +}
>> +
>> +static int aspeed_peci_probe(struct platform_device *pdev)
>> +{
>> + struct aspeed_peci *priv;
>> + struct resource *res;
>> + void __iomem *base;
>> + int ret = 0;
>> +
>> + priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
>> + if (!priv)
>> + return -ENOMEM;
>> +
>> + dev_set_drvdata(&pdev->dev, priv);
>> + priv->dev = &pdev->dev;
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + base = devm_ioremap_resource(&pdev->dev, res);
>> + if (IS_ERR(base))
>> + return PTR_ERR(base);
>> +
>> + priv->regmap = devm_regmap_init_mmio(&pdev->dev, base,
>> + &aspeed_peci_regmap_config);
>> + if (IS_ERR(priv->regmap))
>> + return PTR_ERR(priv->regmap);
>> +
>> + priv->irq = platform_get_irq(pdev, 0);
>> + if (!priv->irq)
>> + return -ENODEV;
>> +
>> + ret = devm_request_irq(&pdev->dev, priv->irq, aspeed_peci_irq_handler,
>> + IRQF_SHARED,
>
> This interrupt is only for the peci device. Why is it marked as shared?
>
You are right. I'll remove the flag.
>> + "peci-aspeed-irq",
>> + priv);
>> + if (ret < 0)
>> + return ret;
>> +
>> + init_completion(&priv->xfer_complete);
>> +
>> + priv->adaper.dev.parent = priv->dev;
>> + priv->adaper.dev.of_node = of_node_get(dev_of_node(priv->dev));
>> + strlcpy(priv->adaper.name, pdev->name, sizeof(priv->adaper.name));
>> + priv->adaper.xfer = aspeed_peci_xfer;
>> + peci_set_adapdata(&priv->adaper, priv);
>> +
>> + ret = aspeed_peci_init_ctrl(priv);
>> + if (ret < 0)
>> + return ret;
>> +
>> + ret = peci_add_adapter(&priv->adaper);
>> + if (ret < 0)
>> + return ret;
>> +
>> + dev_info(&pdev->dev, "peci bus %d registered, irq %d\n",
>> + priv->adaper.nr, priv->irq);
>> +
>> + return 0;
>> +}
>> +
>> +static int aspeed_peci_remove(struct platform_device *pdev)
>> +{
>> + struct aspeed_peci *priv = dev_get_drvdata(&pdev->dev);
>> +
>> + peci_del_adapter(&priv->adaper);
>> + of_node_put(priv->adaper.dev.of_node);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id aspeed_peci_of_table[] = {
>> + { .compatible = "aspeed,ast2400-peci", },
>> + { .compatible = "aspeed,ast2500-peci", },
>> + { }
>> +};
>> +MODULE_DEVICE_TABLE(of, aspeed_peci_of_table);
>> +
>> +static struct platform_driver aspeed_peci_driver = {
>> + .probe = aspeed_peci_probe,
>> + .remove = aspeed_peci_remove,
>> + .driver = {
>> + .name = "peci-aspeed",
>> + .of_match_table = of_match_ptr(aspeed_peci_of_table),
>> + },
>> +};
>> +module_platform_driver(aspeed_peci_driver);
>> +
>> +MODULE_AUTHOR("Ryan Chen <ryan_chen@...eedtech.com>");
>> +MODULE_AUTHOR("Jae Hyun Yoo <jae.hyun.yoo@...ux.intel.com>");
>> +MODULE_DESCRIPTION("Aspeed PECI driver");
>> +MODULE_LICENSE("GPL v2");
>> --
>> 2.16.2
>>
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