Re: [PATCH 07/14] peci: Add peci-aspeed controller driver

Zev Weiss
2021-07-29T18:48:54Z

On Thu, Jul 29, 2021 at 09:03:28AM CDT, Winiarska, Iwona wrote:
>On Tue, 2021-07-27 at 08:49 +0000, Zev Weiss wrote:
>> On Mon, Jul 12, 2021 at 05:04:40PM CDT, Iwona Winiarska wrote:
>> > From: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
>> >
>> > ASPEED AST24xx/AST25xx/AST26xx SoCs supports the PECI electrical
>> > interface (a.k.a PECI wire).
>> >
>> > Signed-off-by: Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
>> > Co-developed-by: Iwona Winiarska <iwona.winiarska@intel.com>
>> > Signed-off-by: Iwona Winiarska <iwona.winiarska@intel.com>
>> > Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
>> > ---
>> > MAINTAINERS                           |   9 +
>> > drivers/peci/Kconfig                  |   6 +
>> > drivers/peci/Makefile                 |   3 +
>> > drivers/peci/controller/Kconfig       |  12 +
>> > drivers/peci/controller/Makefile      |   3 +
>> > drivers/peci/controller/peci-aspeed.c | 501 ++++++++++++++++++++++++++
>> > 6 files changed, 534 insertions(+)
>> > create mode 100644 drivers/peci/controller/Kconfig
>> > create mode 100644 drivers/peci/controller/Makefile
>> > create mode 100644 drivers/peci/controller/peci-aspeed.c
>> >
>> > diff --git a/MAINTAINERS b/MAINTAINERS
>> > index 47411e2b6336..4ba874afa2fa 100644
>> > --- a/MAINTAINERS
>> > +++ b/MAINTAINERS
>> > @@ -2865,6 +2865,15 @@ S:       Maintained
>> > F:      Documentation/hwmon/asc7621.rst
>> > F:      drivers/hwmon/asc7621.c
>> >
>> > +ASPEED PECI CONTROLLER
>> > +M:     Iwona Winiarska <iwona.winiarska@intel.com>
>> > +M:     Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>
>> > +L:     linux-aspeed@lists.ozlabs.org (moderated for non-subscribers)
>> > +L:     openbmc@lists.ozlabs.org (moderated for non-subscribers)
>> > +S:     Supported
>> > +F:     Documentation/devicetree/bindings/peci/peci-aspeed.yaml
>> > +F:     drivers/peci/controller/peci-aspeed.c
>> > +
>> > ASPEED PINCTRL DRIVERS
>> > M:      Andrew Jeffery <andrew@aj.id.au>
>> > L:      linux-aspeed@lists.ozlabs.org (moderated for non-subscribers)
>> > diff --git a/drivers/peci/Kconfig b/drivers/peci/Kconfig
>> > index 601cc3c3c852..0d0ee8009713 100644
>> > --- a/drivers/peci/Kconfig
>> > +++ b/drivers/peci/Kconfig
>> > @@ -12,3 +12,9 @@ menuconfig PECI
>> >
>> >           This support is also available as a module. If so, the module
>> >           will be called peci.
>> > +
>> > +if PECI
>> > +
>> > +source "drivers/peci/controller/Kconfig"
>> > +
>> > +endif # PECI
>> > diff --git a/drivers/peci/Makefile b/drivers/peci/Makefile
>> > index 2bb2f51bcda7..621a993e306a 100644
>> > --- a/drivers/peci/Makefile
>> > +++ b/drivers/peci/Makefile
>> > @@ -3,3 +3,6 @@
>> > # Core functionality
>> > peci-y := core.o sysfs.o
>> > obj-$(CONFIG_PECI) += peci.o
>> > +
>> > +# Hardware specific bus drivers
>> > +obj-y += controller/
>> > diff --git a/drivers/peci/controller/Kconfig
>> > b/drivers/peci/controller/Kconfig
>> > new file mode 100644
>> > index 000000000000..8ddbe494677f
>> > --- /dev/null
>> > +++ b/drivers/peci/controller/Kconfig
>> > @@ -0,0 +1,12 @@
>> > +# SPDX-License-Identifier: GPL-2.0-only
>> > +
>> > +config PECI_ASPEED
>> > +       tristate "ASPEED PECI support"
>> > +       depends on ARCH_ASPEED || COMPILE_TEST
>> > +       depends on OF
>> > +       depends on HAS_IOMEM
>> > +       help
>> > +         Enable this driver if you want to support ASPEED PECI controller.
>> > +
>> > +         This driver can be also build as a module. If so, the module
>> > +         will be called peci-aspeed.
>> > diff --git a/drivers/peci/controller/Makefile
>> > b/drivers/peci/controller/Makefile
>> > new file mode 100644
>> > index 000000000000..022c28ef1bf0
>> > --- /dev/null
>> > +++ b/drivers/peci/controller/Makefile
>> > @@ -0,0 +1,3 @@
>> > +# SPDX-License-Identifier: GPL-2.0-only
>> > +
>> > +obj-$(CONFIG_PECI_ASPEED)      += peci-aspeed.o
>> > diff --git a/drivers/peci/controller/peci-aspeed.c
>> > b/drivers/peci/controller/peci-aspeed.c
>> > new file mode 100644
>> > index 000000000000..888b46383ea4
>> > --- /dev/null
>> > +++ b/drivers/peci/controller/peci-aspeed.c
>> > @@ -0,0 +1,501 @@
>> > +// SPDX-License-Identifier: GPL-2.0-only
>> > +// Copyright (C) 2012-2017 ASPEED Technology Inc.
>> > +// Copyright (c) 2018-2021 Intel Corporation
>> > +
>> > +#include <linux/bitfield.h>
>> > +#include <linux/clk.h>
>> > +#include <linux/delay.h>
>> > +#include <linux/interrupt.h>
>> > +#include <linux/io.h>
>> > +#include <linux/iopoll.h>
>> > +#include <linux/jiffies.h>
>> > +#include <linux/module.h>
>> > +#include <linux/of.h>
>> > +#include <linux/peci.h>
>> > +#include <linux/platform_device.h>
>> > +#include <linux/reset.h>
>> > +
>> > +#include <asm/unaligned.h>
>> > +
>> > +/* ASPEED PECI Registers */
>> > +/* Control Register */
>> > +#define ASPEED_PECI_CTRL                       0x00
>> > +#define   ASPEED_PECI_CTRL_SAMPLING_MASK       GENMASK(19, 16)
>> > +#define   ASPEED_PECI_CTRL_READ_MODE_MASK      GENMASK(13, 12)
>> > +#define   ASPEED_PECI_CTRL_READ_MODE_COUNT     BIT(12)
>> > +#define   ASPEED_PECI_CTRL_READ_MODE_DBG       BIT(13)
>>
>> Nitpick: might be nice to keep things in a consistent descending order
>> here (13 then 12).
>>
>
>Sure, I'll change it in v2.
>
>> > +#define   ASPEED_PECI_CTRL_CLK_SOURCE_MASK     BIT(11)
>>
>> _MASK suffix seems out of place on this one.
>
>Ack.
>
>>
>> > +#define   ASPEED_PECI_CTRL_CLK_DIV_MASK                GENMASK(10, 8)
>> > +#define   ASPEED_PECI_CTRL_INVERT_OUT          BIT(7)
>> > +#define   ASPEED_PECI_CTRL_INVERT_IN           BIT(6)
>> > +#define   ASPEED_PECI_CTRL_BUS_CONTENT_EN      BIT(5)
>>
>> It *is* already kind of a long macro name, but abbreviating "contention"
>> to "content" seems a bit confusing; I'd suggest keeping the extra three
>> characters (or maybe drop the _EN suffix if you want to avoid making it
>> even longer).
>>
>
>You're right - it'll be renamed properly in v2.
>
>> > +#define   ASPEED_PECI_CTRL_PECI_EN             BIT(4)
>> > +#define   ASPEED_PECI_CTRL_PECI_CLK_EN         BIT(0)
>> > +
>> > +/* Timing Negotiation Register */
>> > +#define ASPEED_PECI_TIMING_NEGOTIATION         0x04
>> > +#define   ASPEED_PECI_TIMING_MESSAGE_MASK      GENMASK(15, 8)
>> > +#define   ASPEED_PECI_TIMING_ADDRESS_MASK      GENMASK(7, 0)
>> > +
>> > +/* Command Register */
>> > +#define ASPEED_PECI_CMD                                0x08
>> > +#define   ASPEED_PECI_CMD_PIN_MON              BIT(31)
>> > +#define   ASPEED_PECI_CMD_STS_MASK             GENMASK(27, 24)
>> > +#define     ASPEED_PECI_CMD_STS_ADDR_T_NEGO    0x3
>> > +#define   ASPEED_PECI_CMD_IDLE_MASK            \
>> > +         (ASPEED_PECI_CMD_STS_MASK | ASPEED_PECI_CMD_PIN_MON)
>> > +#define   ASPEED_PECI_CMD_FIRE                 BIT(0)
>> > +
>> > +/* Read/Write Length Register */
>> > +#define ASPEED_PECI_RW_LENGTH                  0x0c
>> > +#define   ASPEED_PECI_AW_FCS_EN                        BIT(31)
>> > +#define   ASPEED_PECI_READ_LEN_MASK            GENMASK(23, 16)
>> > +#define   ASPEED_PECI_WRITE_LEN_MASK           GENMASK(15, 8)
>> > +#define   ASPEED_PECI_TAGET_ADDR_MASK          GENMASK(7, 0)
>>
>> s/TAGET/TARGET/
>>
>
>Ack.
>
>> > +
>> > +/* Expected FCS Data Register */
>> > +#define ASPEED_PECI_EXP_FCS                    0x10
>> > +#define   ASPEED_PECI_EXP_READ_FCS_MASK                GENMASK(23, 16)
>> > +#define   ASPEED_PECI_EXP_AW_FCS_AUTO_MASK     GENMASK(15, 8)
>> > +#define   ASPEED_PECI_EXP_WRITE_FCS_MASK       GENMASK(7, 0)
>> > +
>> > +/* Captured FCS Data Register */
>> > +#define ASPEED_PECI_CAP_FCS                    0x14
>> > +#define   ASPEED_PECI_CAP_READ_FCS_MASK                GENMASK(23, 16)
>> > +#define   ASPEED_PECI_CAP_WRITE_FCS_MASK       GENMASK(7, 0)
>> > +
>> > +/* Interrupt Register */
>> > +#define ASPEED_PECI_INT_CTRL                   0x18
>> > +#define   ASPEED_PECI_TIMING_NEGO_SEL_MASK     GENMASK(31, 30)
>> > +#define     ASPEED_PECI_1ST_BIT_OF_ADDR_NEGO   0
>> > +#define     ASPEED_PECI_2ND_BIT_OF_ADDR_NEGO   1
>> > +#define     ASPEED_PECI_MESSAGE_NEGO           2
>> > +#define   ASPEED_PECI_INT_MASK                 GENMASK(4, 0)
>> > +#define   ASPEED_PECI_INT_BUS_TIMEOUT          BIT(4)
>> > +#define   ASPEED_PECI_INT_BUS_CONNECT          BIT(3)
>>
>> s/CONNECT/CONTENTION/
>
>Ack.
>
>>
>> > +#define   ASPEED_PECI_INT_W_FCS_BAD            BIT(2)
>> > +#define   ASPEED_PECI_INT_W_FCS_ABORT          BIT(1)
>> > +#define   ASPEED_PECI_INT_CMD_DONE             BIT(0)
>> > +
>> > +/* Interrupt Status Register */
>> > +#define ASPEED_PECI_INT_STS                    0x1c
>> > +#define   ASPEED_PECI_INT_TIMING_RESULT_MASK   GENMASK(29, 16)
>> > +         /* bits[4..0]: Same bit fields in the 'Interrupt Register' */
>> > +
>> > +/* Rx/Tx Data Buffer Registers */
>> > +#define ASPEED_PECI_W_DATA0                    0x20
>> > +#define ASPEED_PECI_W_DATA1                    0x24
>> > +#define ASPEED_PECI_W_DATA2                    0x28
>> > +#define ASPEED_PECI_W_DATA3                    0x2c
>> > +#define ASPEED_PECI_R_DATA0                    0x30
>> > +#define ASPEED_PECI_R_DATA1                    0x34
>> > +#define ASPEED_PECI_R_DATA2                    0x38
>> > +#define ASPEED_PECI_R_DATA3                    0x3c
>> > +#define ASPEED_PECI_W_DATA4                    0x40
>> > +#define ASPEED_PECI_W_DATA5                    0x44
>> > +#define ASPEED_PECI_W_DATA6                    0x48
>> > +#define ASPEED_PECI_W_DATA7                    0x4c
>> > +#define ASPEED_PECI_R_DATA4                    0x50
>> > +#define ASPEED_PECI_R_DATA5                    0x54
>> > +#define ASPEED_PECI_R_DATA6                    0x58
>> > +#define ASPEED_PECI_R_DATA7                    0x5c
>> > +#define   ASPEED_PECI_DATA_BUF_SIZE_MAX                32
>> > +
>> > +/* Timing Negotiation */
>> > +#define ASPEED_PECI_RD_SAMPLING_POINT_DEFAULT  8
>> > +#define ASPEED_PECI_RD_SAMPLING_POINT_MAX      (BIT(4) - 1)
>> > +#define ASPEED_PECI_CLK_DIV_DEFAULT            0
>> > +#define ASPEED_PECI_CLK_DIV_MAX                        (BIT(3) - 1)
>> > +#define ASPEED_PECI_MSG_TIMING_DEFAULT         1
>> > +#define ASPEED_PECI_MSG_TIMING_MAX             (BIT(8) - 1)
>> > +#define ASPEED_PECI_ADDR_TIMING_DEFAULT                1
>> > +#define ASPEED_PECI_ADDR_TIMING_MAX            (BIT(8) - 1)
>> > +
>> > +/* Timeout */
>> > +#define ASPEED_PECI_IDLE_CHECK_TIMEOUT_US      (50 * USEC_PER_MSEC)
>> > +#define ASPEED_PECI_IDLE_CHECK_INTERVAL_US     (10 * USEC_PER_MSEC)
>> > +#define ASPEED_PECI_CMD_TIMEOUT_MS_DEFAULT     (1000)
>> > +#define ASPEED_PECI_CMD_TIMEOUT_MS_MAX         (1000)
>> > +
>> > +struct aspeed_peci {
>> > +       struct peci_controller controller;
>> > +       struct device *dev;
>> > +       void __iomem *base;
>> > +       struct clk *clk;
>> > +       struct reset_control *rst;
>> > +       int irq;
>> > +       spinlock_t lock; /* to sync completion status handling */
>> > +       struct completion xfer_complete;
>> > +       u32 status;
>> > +       u32 cmd_timeout_ms;
>> > +       u32 msg_timing;
>> > +       u32 addr_timing;
>> > +       u32 rd_sampling_point;
>> > +       u32 clk_div;
>> > +};
>> > +
>> > +static inline struct aspeed_peci *to_aspeed_peci(struct peci_controller *a)
>> > +{
>> > +       return container_of(a, struct aspeed_peci, controller);
>> > +}
>> > +
>> > +static void aspeed_peci_init_regs(struct aspeed_peci *priv)
>> > +{
>> > +       u32 val;
>> > +
>> > +       val = FIELD_PREP(ASPEED_PECI_CTRL_CLK_DIV_MASK,
>> > ASPEED_PECI_CLK_DIV_DEFAULT);
>> > +       val |= ASPEED_PECI_CTRL_PECI_CLK_EN;
>> > +       writel(val, priv->base + ASPEED_PECI_CTRL);
>> > +       /*
>> > +        * Timing negotiation period setting.
>> > +        * The unit of the programmed value is 4 times of PECI clock period.
>> > +        */
>> > +       val = FIELD_PREP(ASPEED_PECI_TIMING_MESSAGE_MASK, priv->msg_timing);
>> > +       val |= FIELD_PREP(ASPEED_PECI_TIMING_ADDRESS_MASK, priv-
>> > >addr_timing);
>> > +       writel(val, priv->base + ASPEED_PECI_TIMING_NEGOTIATION);
>> > +
>> > +       /* Clear interrupts */
>> > +       val = readl(priv->base + ASPEED_PECI_INT_STS) |
>> > ASPEED_PECI_INT_MASK;
>>
>> This should be & instead of |, I'm guessing?
>>
>
>I believe the idea is to unconditionally clear all known interrupt status bits,
>(irrelevant of what value is already set in regs), and the HW expects that this
>is done by writing 1 to corresponding bits.
>

Ah -- I had been thinking we needed to ensure that we were only writing
zeros to reserved or RO bits, but I suppose re-writing whatever bit
pattern they provide on a read is probably okay (I'm having trouble
finding any explicit statement either way in the datasheet I've got).

>> > +       writel(val, priv->base + ASPEED_PECI_INT_STS);
>> > +
>> > +       /* Set timing negotiation mode and enable interrupts */
>> > +       val = FIELD_PREP(ASPEED_PECI_TIMING_NEGO_SEL_MASK,
>> > ASPEED_PECI_1ST_BIT_OF_ADDR_NEGO);
>> > +       val |= ASPEED_PECI_INT_MASK;
>> > +       writel(val, priv->base + ASPEED_PECI_INT_CTRL);
>> > +
>> > +       val = FIELD_PREP(ASPEED_PECI_CTRL_SAMPLING_MASK, priv-
>> > >rd_sampling_point);
>> > +       val |= FIELD_PREP(ASPEED_PECI_CTRL_CLK_DIV_MASK, priv->clk_div);
>> > +       val |= ASPEED_PECI_CTRL_PECI_EN;
>> > +       val |= ASPEED_PECI_CTRL_PECI_CLK_EN;
>> > +       writel(val, priv->base + ASPEED_PECI_CTRL);
>> > +}
>> > +
>> > +static inline int aspeed_peci_check_idle(struct aspeed_peci *priv)
>> > +{
>> > +       u32 cmd_sts = readl(priv->base + ASPEED_PECI_CMD);
>> > +
>> > +       if (FIELD_GET(ASPEED_PECI_CMD_STS_MASK, cmd_sts) ==
>> > ASPEED_PECI_CMD_STS_ADDR_T_NEGO)
>> > +               aspeed_peci_init_regs(priv);
>> > +
>> > +       return readl_poll_timeout(priv->base + ASPEED_PECI_CMD,
>> > +                                 cmd_sts,
>> > +                                 !(cmd_sts & ASPEED_PECI_CMD_IDLE_MASK),
>> > +                                 ASPEED_PECI_IDLE_CHECK_INTERVAL_US,
>> > +                                 ASPEED_PECI_IDLE_CHECK_TIMEOUT_US);
>> > +}
>> > +
>> > +static int aspeed_peci_xfer(struct peci_controller *controller,
>> > +                           u8 addr, struct peci_request *req)
>> > +{
>> > +       struct aspeed_peci *priv = to_aspeed_peci(controller);
>> > +       unsigned long flags, timeout = msecs_to_jiffies(priv-
>> > >cmd_timeout_ms);
>> > +       u32 peci_head;
>> > +       int ret;
>> > +
>> > +       if (req->tx.len > ASPEED_PECI_DATA_BUF_SIZE_MAX ||
>> > +           req->rx.len > ASPEED_PECI_DATA_BUF_SIZE_MAX)
>> > +               return -EINVAL;
>> > +
>> > +       /* Check command sts and bus idle state */
>> > +       ret = aspeed_peci_check_idle(priv);
>> > +       if (ret)
>> > +               return ret; /* -ETIMEDOUT */
>> > +
>> > +       spin_lock_irqsave(&priv->lock, flags);
>> > +       reinit_completion(&priv->xfer_complete);
>> > +
>> > +       peci_head = FIELD_PREP(ASPEED_PECI_TAGET_ADDR_MASK, addr) |
>> > +                   FIELD_PREP(ASPEED_PECI_WRITE_LEN_MASK, req->tx.len) |
>> > +                   FIELD_PREP(ASPEED_PECI_READ_LEN_MASK, req->rx.len);
>> > +
>> > +       writel(peci_head, priv->base + ASPEED_PECI_RW_LENGTH);
>> > +
>> > +       memcpy_toio(priv->base + ASPEED_PECI_W_DATA0, req->tx.buf,
>> > +                   req->tx.len > 16 ? 16 : req->tx.len);
>>
>> min(req->tx.len, 16) for the third argument there might be a bit
>> clearer.
>
>Ack.
>
>>
>> > +       if (req->tx.len > 16)
>> > +               memcpy_toio(priv->base + ASPEED_PECI_W_DATA4, req->tx.buf +
>> > 16,
>> > +                           req->tx.len - 16);
>> > +
>> > +       dev_dbg(priv->dev, "HEAD : 0x%08x\n", peci_head);
>> > +       print_hex_dump_bytes("TX : ", DUMP_PREFIX_NONE, req->tx.buf, req-
>> > >tx.len);
>> > +
>> > +       priv->status = 0;
>> > +       writel(ASPEED_PECI_CMD_FIRE, priv->base + ASPEED_PECI_CMD);
>> > +       spin_unlock_irqrestore(&priv->lock, flags);
>> > +
>> > +       ret = wait_for_completion_interruptible_timeout(&priv-
>> > >xfer_complete, timeout);
>> > +       if (ret < 0)
>> > +               return ret;
>> > +
>> > +       if (ret == 0) {
>> > +               dev_dbg(priv->dev, "Timeout waiting for a response!\n");
>> > +               return -ETIMEDOUT;
>> > +       }
>> > +
>> > +       spin_lock_irqsave(&priv->lock, flags);
>> > +
>> > +       writel(0, priv->base + ASPEED_PECI_CMD);
>> > +
>> > +       if (priv->status != ASPEED_PECI_INT_CMD_DONE) {
>> > +               spin_unlock_irqrestore(&priv->lock, flags);
>> > +               dev_dbg(priv->dev, "No valid response!\n");
>> > +               return -EIO;
>> > +       }
>> > +
>> > +       spin_unlock_irqrestore(&priv->lock, flags);
>> > +
>> > +       memcpy_fromio(req->rx.buf, priv->base + ASPEED_PECI_R_DATA0,
>> > +                     req->rx.len > 16 ? 16 : req->rx.len);
>>
>> Likewise, min(req->rx.len, 16) here.
>
>Ack.
>
>>
>> > +       if (req->rx.len > 16)
>> > +               memcpy_fromio(req->rx.buf + 16, priv->base +
>> > ASPEED_PECI_R_DATA4,
>> > +                             req->rx.len - 16);
>> > +
>> > +       print_hex_dump_bytes("RX : ", DUMP_PREFIX_NONE, req->rx.buf, req-
>> > >rx.len);
>> > +
>> > +       return 0;
>> > +}
>> > +
>> > +static irqreturn_t aspeed_peci_irq_handler(int irq, void *arg)
>> > +{
>> > +       struct aspeed_peci *priv = arg;
>> > +       u32 status;
>> > +
>> > +       spin_lock(&priv->lock);
>> > +       status = readl(priv->base + ASPEED_PECI_INT_STS);
>> > +       writel(status, priv->base + ASPEED_PECI_INT_STS);
>> > +       priv->status |= (status & ASPEED_PECI_INT_MASK);
>> > +
>> > +       /*
>> > +        * In most cases, interrupt bits will be set one by one but also
>> > note
>> > +        * that multiple interrupt bits could be set at the same time.
>> > +        */
>> > +       if (status & ASPEED_PECI_INT_BUS_TIMEOUT)
>> > +               dev_dbg_ratelimited(priv->dev,
>> > "ASPEED_PECI_INT_BUS_TIMEOUT\n");
>> > +
>> > +       if (status & ASPEED_PECI_INT_BUS_CONNECT)
>> > +               dev_dbg_ratelimited(priv->dev,
>> > "ASPEED_PECI_INT_BUS_CONNECT\n");
>>
>> s/CONNECT/CONTENTION/ here too (in the message string).
>
>Ack.
>
>>
>> > +
>> > +       if (status & ASPEED_PECI_INT_W_FCS_BAD)
>> > +               dev_dbg_ratelimited(priv->dev,
>> > "ASPEED_PECI_INT_W_FCS_BAD\n");
>> > +
>> > +       if (status & ASPEED_PECI_INT_W_FCS_ABORT)
>> > +               dev_dbg_ratelimited(priv->dev,
>> > "ASPEED_PECI_INT_W_FCS_ABORT\n");
>>
>> Bus contention can of course arise legitimately, and I suppose an
>> offline host CPU might result in a timeout, so dbg seems fine for those
>> (though as Dan suggests, making some counters available seems like a
>> good idea, especially for contention).  Are the FCS error cases
>> significant enough to warrant something less likely to go unnoticed
>> though?  (e.g. dev_warn_ratelimited() or something?)
>
>It's similar story for FCS errors (can occur legitimately).
>We can hit ASPEED_PECI_INT_W_FCS_BAD in completely valid scenarios, e.g.
>unsuccessful detect during rescan.
>In case of ASPEED_PECI_INT_W_FCS_ABORT - caller can hit this by providing e.g.
>malformed command. Since we do return -EIO in this case, caller can print its
>own log. In other words, it's not always an error condition in peci-aspeed (or
>HW). Moreover, if we ever expose more direct PECI access to userspace (pecidev,
>or something similar) this warn would be user triggerable.
>
>I would prefer to keep this at debug level for now.
>

Okay, I guess that's alright -- counters of some sort (e.g. in sysfs)
would be a nice thing to supplement that with for diagnosing problems
though, I think.

>>
>> > +
>> > +       /*
>> > +        * All commands should be ended up with a ASPEED_PECI_INT_CMD_DONE
>> > bit
>> > +        * set even in an error case.
>> > +        */
>> > +       if (status & ASPEED_PECI_INT_CMD_DONE)
>> > +               complete(&priv->xfer_complete);
>> > +
>> > +       spin_unlock(&priv->lock);
>> > +
>> > +       return IRQ_HANDLED;
>> > +}
>> > +
>> > +static void __sanitize_clock_divider(struct aspeed_peci *priv)
>> > +{
>> > +       u32 clk_div;
>> > +       int ret;
>> > +
>> > +       ret = device_property_read_u32(priv->dev, "clock-divider",
>> > &clk_div);
>> > +       if (ret) {
>> > +               clk_div = ASPEED_PECI_CLK_DIV_DEFAULT;
>> > +       } else if (clk_div > ASPEED_PECI_CLK_DIV_MAX) {
>> > +               dev_warn(priv->dev, "Invalid clock-divider: %u, Using
>> > default: %u\n",
>> > +                        clk_div, ASPEED_PECI_CLK_DIV_DEFAULT);
>> > +
>> > +               clk_div = ASPEED_PECI_CLK_DIV_DEFAULT;
>> > +       }
>> > +
>> > +       priv->clk_div = clk_div;
>> > +}
>> > +
>>
>> The naming of these __sanitize_*() functions is a bit inconsistent with
>> the rest of the driver -- though given how similar they all look, could
>> they instead be refactored into a single helper function taking
>> property-name, default-value, and max-value parameters?
>
>You're right - we can have a single helper.
>
>Regarding naming, the idea was to have a simple "inner" helper function to be
>called by the more appropriately named aspeed_peci_device_property_sanitize().
>
>Do you think I should use "aspeed_peci_" prefix in this function name or just
>remove "__" and name it "sanitize_property()"?
>

I just think it's generally nice to have function names give some
indication as to what part of the kernel they belong to -- that way when
they show up in a stack bracktrace or a symbol list (e.g. for ftrace
usage and such) it's clearer what they are (and reduces the likelihood
of name collisions and ensuing confusion).

>>
>> > +static void __sanitize_msg_timing(struct aspeed_peci *priv)
>> > +{
>> > +       u32 msg_timing;
>> > +       int ret;
>> > +
>> > +       ret = device_property_read_u32(priv->dev, "msg-timing",
>> > &msg_timing);
>> > +       if (ret) {
>> > +               msg_timing = ASPEED_PECI_MSG_TIMING_DEFAULT;
>> > +       } else if (msg_timing > ASPEED_PECI_MSG_TIMING_MAX) {
>> > +               dev_warn(priv->dev, "Invalid msg-timing : %u, Use default :
>> > %u\n",
>> > +                        msg_timing, ASPEED_PECI_MSG_TIMING_DEFAULT);
>> > +
>> > +               msg_timing = ASPEED_PECI_MSG_TIMING_DEFAULT;
>> > +       }
>> > +
>> > +       priv->msg_timing = msg_timing;
>> > +}
>> > +
>> > +static void __sanitize_addr_timing(struct aspeed_peci *priv)
>> > +{
>> > +       u32 addr_timing;
>> > +       int ret;
>> > +
>> > +       ret = device_property_read_u32(priv->dev, "addr-timing",
>> > &addr_timing);
>> > +       if (ret) {
>> > +               addr_timing = ASPEED_PECI_ADDR_TIMING_DEFAULT;
>> > +       } else if (addr_timing > ASPEED_PECI_ADDR_TIMING_MAX) {
>> > +               dev_warn(priv->dev, "Invalid addr-timing : %u, Use default :
>> > %u\n",
>> > +                        addr_timing, ASPEED_PECI_ADDR_TIMING_DEFAULT);
>> > +
>> > +               addr_timing = ASPEED_PECI_ADDR_TIMING_DEFAULT;
>> > +       }
>> > +
>> > +       priv->addr_timing = addr_timing;
>> > +}
>> > +
>> > +static void __sanitize_rd_sampling_point(struct aspeed_peci *priv)
>> > +{
>> > +       u32 rd_sampling_point;
>> > +       int ret;
>> > +
>> > +       ret = device_property_read_u32(priv->dev, "rd-sampling-point",
>> > &rd_sampling_point);
>> > +       if (ret) {
>> > +               rd_sampling_point = ASPEED_PECI_RD_SAMPLING_POINT_DEFAULT;
>> > +       } else if (rd_sampling_point > ASPEED_PECI_RD_SAMPLING_POINT_MAX) {
>> > +               dev_warn(priv->dev, "Invalid rd-sampling-point: %u, Use
>> > default : %u\n",
>> > +                        rd_sampling_point,
>> > ASPEED_PECI_RD_SAMPLING_POINT_DEFAULT);
>> > +
>> > +               rd_sampling_point = ASPEED_PECI_RD_SAMPLING_POINT_DEFAULT;
>> > +       }
>> > +
>> > +       priv->rd_sampling_point = rd_sampling_point;
>> > +}
>> > +
>> > +static void __sanitize_cmd_timeout(struct aspeed_peci *priv)
>> > +{
>> > +       u32 timeout;
>> > +       int ret;
>> > +
>> > +       ret = device_property_read_u32(priv->dev, "cmd-timeout-ms",
>> > &timeout);
>> > +       if (ret) {
>> > +               timeout = ASPEED_PECI_CMD_TIMEOUT_MS_DEFAULT;
>> > +       } else if (timeout > ASPEED_PECI_CMD_TIMEOUT_MS_MAX || timeout == 0)
>> > {
>> > +               dev_warn(priv->dev, "Invalid cmd-timeout-ms: %u, Use
>> > default: %u\n",
>> > +                        timeout, ASPEED_PECI_CMD_TIMEOUT_MS_DEFAULT);
>> > +
>> > +               timeout = ASPEED_PECI_CMD_TIMEOUT_MS_DEFAULT;
>> > +       }
>> > +
>> > +       priv->cmd_timeout_ms = timeout;
>> > +}
>> > +
>> > +static void aspeed_peci_device_property_sanitize(struct aspeed_peci *priv)
>> > +{
>> > +       __sanitize_clock_divider(priv);
>> > +       __sanitize_msg_timing(priv);
>> > +       __sanitize_addr_timing(priv);
>> > +       __sanitize_rd_sampling_point(priv);
>> > +       __sanitize_cmd_timeout(priv);
>> > +}
>> > +
>> > +static void aspeed_peci_disable_clk(void *data)
>> > +{
>> > +       clk_disable_unprepare(data);
>> > +}
>> > +
>> > +static int aspeed_peci_init_ctrl(struct aspeed_peci *priv)
>> > +{
>> > +       int ret;
>> > +
>> > +       priv->clk = devm_clk_get(priv->dev, NULL);
>> > +       if (IS_ERR(priv->clk))
>> > +               return dev_err_probe(priv->dev, PTR_ERR(priv->clk), "Failed
>> > to get clk source\n");
>> > +
>> > +       ret = clk_prepare_enable(priv->clk);
>> > +       if (ret) {
>> > +               dev_err(priv->dev, "Failed to enable clock\n");
>> > +               return ret;
>> > +       }
>> > +
>> > +       ret = devm_add_action_or_reset(priv->dev, aspeed_peci_disable_clk,
>> > priv->clk);
>> > +       if (ret)
>> > +               return ret;
>> > +
>> > +       aspeed_peci_device_property_sanitize(priv);
>> > +
>> > +       aspeed_peci_init_regs(priv);
>> > +
>> > +       return 0;
>> > +}
>> > +
>> > +static int aspeed_peci_probe(struct platform_device *pdev)
>> > +{
>> > +       struct aspeed_peci *priv;
>> > +       int ret;
>> > +
>> > +       priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
>> > +       if (!priv)
>> > +               return -ENOMEM;
>> > +
>> > +       priv->dev = &pdev->dev;
>> > +       dev_set_drvdata(priv->dev, priv);
>> > +
>> > +       priv->base = devm_platform_ioremap_resource(pdev, 0);
>> > +       if (IS_ERR(priv->base))
>> > +               return PTR_ERR(priv->base);
>> > +
>> > +       priv->irq = platform_get_irq(pdev, 0);
>> > +       if (!priv->irq)
>> > +               return priv->irq;
>> > +
>> > +       ret = devm_request_irq(&pdev->dev, priv->irq,
>> > aspeed_peci_irq_handler,
>> > +                              0, "peci-aspeed-irq", priv);
>>
>> Might as well drop the "-irq" suffix here?  (Seems a bit redundant, and
>> a quick glance through /proc/interrupts on the systems I have at hand
>> doesn't show anything else following that convention.)
>
>I'll remove it.
>
>Thank you
>-Iwona
>
>>
>> > +       if (ret)
>> > +               return ret;
>> > +
>> > +       init_completion(&priv->xfer_complete);
>> > +       spin_lock_init(&priv->lock);
>> > +
>> > +       priv->controller.xfer = aspeed_peci_xfer;
>> > +
>> > +       priv->rst = devm_reset_control_get(&pdev->dev, NULL);
>> > +       if (IS_ERR(priv->rst)) {
>> > +               dev_err(&pdev->dev, "Missing or invalid reset controller
>> > entry\n");
>> > +               return PTR_ERR(priv->rst);
>> > +       }
>> > +       reset_control_deassert(priv->rst);
>> > +
>> > +       ret = aspeed_peci_init_ctrl(priv);
>> > +       if (ret)
>> > +               return ret;
>> > +
>> > +       return peci_controller_add(&priv->controller, priv->dev);
>> > +}
>> > +
>> > +static int aspeed_peci_remove(struct platform_device *pdev)
>> > +{
>> > +       struct aspeed_peci *priv = dev_get_drvdata(&pdev->dev);
>> > +
>> > +       peci_controller_remove(&priv->controller);
>> > +       reset_control_assert(priv->rst);
>> > +
>> > +       return 0;
>> > +}
>> > +
>> > +static const struct of_device_id aspeed_peci_of_table[] = {
>> > +       { .compatible = "aspeed,ast2400-peci", },
>> > +       { .compatible = "aspeed,ast2500-peci", },
>> > +       { .compatible = "aspeed,ast2600-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 = aspeed_peci_of_table,
>> > +       },
>> > +};
>> > +module_platform_driver(aspeed_peci_driver);
>> > +
>> > +MODULE_AUTHOR("Ryan Chen <ryan_chen@aspeedtech.com>");
>> > +MODULE_AUTHOR("Jae Hyun Yoo <jae.hyun.yoo@linux.intel.com>");
>> > +MODULE_DESCRIPTION("ASPEED PECI driver");
>> > +MODULE_LICENSE("GPL");
>> > +MODULE_IMPORT_NS(PECI);
>> > --
>> > 2.31.1
>