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Date: Mon, 10 Apr 2017 05:51:02 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@...ux.intel.com>, andy@...radead.org,
qipeng.zha@...el.com, dvhart@...radead.org
Cc: wim@...ana.be, sathyaosid@...il.com, david.e.box@...ux.intel.com,
rajneesh.bhardwaj@...el.com, platform-driver-x86@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-watchdog@...r.kernel.org
Subject: Re: [PATCH v7 3/6] watchdog: iTCO_wdt: cleanup set/unset
no_reboot_bit functions
On 04/09/2017 03:00 PM, Kuppuswamy Sathyanarayanan wrote:
> iTCO_wdt no_reboot_bit set/unset functions has lot of common code between
> them. So merging these two functions into a single update function would
> remove these unnecessary code duplications. This patch fixes this issue
> by creating a no_reboot_bit update function to handle both set/unset
> functions.
>
> Also checking for iTCO version every time you make no_reboot_bit set/unset
> call is inefficient and makes the code look complex. This can be improved
> by performing this check once during device probe and selecting the
> appropriate no_reboot_bit update function. This patch fixes this issue
> by splitting the update function into multiple helper functions.
>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@...ux.intel.com>
Reviewed-by: Guenter Roeck <linux@...ck-us.net>
> ---
> drivers/watchdog/iTCO_wdt.c | 83 +++++++++++++++++++++++++++------------------
> 1 file changed, 50 insertions(+), 33 deletions(-)
>
> Changes since v6:
> * make iTCO_wdt_no_reboot_bit_setup() static
> * remove inline specifier for update_no_reboot_bit helper functions.
>
> Changes since v5:
> * Changed update function argument name from "status" to "set".
> * Fixed commit history.
> * Changed update function name to use "bit" instead of "flag"
> * Addressed Andy's comment on creating multiple helper functions.
>
> diff --git a/drivers/watchdog/iTCO_wdt.c b/drivers/watchdog/iTCO_wdt.c
> index 3d0abc0..a629933 100644
> --- a/drivers/watchdog/iTCO_wdt.c
> +++ b/drivers/watchdog/iTCO_wdt.c
> @@ -106,6 +106,8 @@ struct iTCO_wdt_private {
> struct pci_dev *pci_dev;
> /* whether or not the watchdog has been suspended */
> bool suspended;
> + /* no reboot update function pointer */
> + int (*update_no_reboot_bit)(void *p, bool set);
> };
>
> /* module parameters */
> @@ -170,48 +172,61 @@ static inline u32 no_reboot_bit(struct iTCO_wdt_private *p)
> return enable_bit;
> }
>
> -static void iTCO_wdt_set_NO_REBOOT_bit(struct iTCO_wdt_private *p)
> +static int update_no_reboot_bit_def(void *priv, bool set)
> {
> - u32 val32;
> -
> - /* Set the NO_REBOOT bit: this disables reboots */
> - if (p->iTCO_version >= 2) {
> - val32 = readl(p->gcs_pmc);
> - val32 |= no_reboot_bit(p);
> - writel(val32, p->gcs_pmc);
> - } else if (p->iTCO_version == 1) {
> - pci_read_config_dword(p->pci_dev, 0xd4, &val32);
> - val32 |= no_reboot_bit(p);
> - pci_write_config_dword(p->pci_dev, 0xd4, val32);
> - }
> + return 0;
> }
>
> -static int iTCO_wdt_unset_NO_REBOOT_bit(struct iTCO_wdt_private *p)
> +static int update_no_reboot_bit_pci(void *priv, bool set)
> {
> - u32 enable_bit = no_reboot_bit(p);
> - u32 val32 = 0;
> + struct iTCO_wdt_private *p = priv;
> + u32 val32 = 0, newval32 = 0;
>
> - /* Unset the NO_REBOOT bit: this enables reboots */
> - if (p->iTCO_version >= 2) {
> - val32 = readl(p->gcs_pmc);
> - val32 &= ~enable_bit;
> - writel(val32, p->gcs_pmc);
> + pci_read_config_dword(p->pci_dev, 0xd4, &val32);
> + if (set)
> + val32 |= no_reboot_bit(p);
> + else
> + val32 &= ~no_reboot_bit(p);
> + pci_write_config_dword(p->pci_dev, 0xd4, val32);
> + pci_read_config_dword(p->pci_dev, 0xd4, &newval32);
>
> - val32 = readl(p->gcs_pmc);
> - } else if (p->iTCO_version == 1) {
> - pci_read_config_dword(p->pci_dev, 0xd4, &val32);
> - val32 &= ~enable_bit;
> - pci_write_config_dword(p->pci_dev, 0xd4, val32);
> + /* make sure the update is successful */
> + if (val32 != newval32)
> + return -EIO;
>
> - pci_read_config_dword(p->pci_dev, 0xd4, &val32);
> - }
> + return 0;
> +}
> +
> +static int update_no_reboot_bit_mem(void *priv, bool set)
> +{
> + struct iTCO_wdt_private *p = priv;
> + u32 val32 = 0, newval32 = 0;
> +
> + val32 = readl(p->gcs_pmc);
> + if (set)
> + val32 |= no_reboot_bit(p);
> + else
> + val32 &= ~no_reboot_bit(p);
> + writel(val32, p->gcs_pmc);
> + newval32 = readl(p->gcs_pmc);
>
> - if (val32 & enable_bit)
> + /* make sure the update is successful */
> + if (val32 != newval32)
> return -EIO;
>
> return 0;
> }
>
> +static void iTCO_wdt_no_reboot_bit_setup(struct iTCO_wdt_private *p)
> +{
> + if (p->iTCO_version >= 2)
> + p->update_no_reboot_bit = update_no_reboot_bit_mem;
> + else if (p->iTCO_version == 1)
> + p->update_no_reboot_bit = update_no_reboot_bit_pci;
> + else
> + p->update_no_reboot_bit = update_no_reboot_bit_def;
> +}
> +
> static int iTCO_wdt_start(struct watchdog_device *wd_dev)
> {
> struct iTCO_wdt_private *p = watchdog_get_drvdata(wd_dev);
> @@ -222,7 +237,7 @@ static int iTCO_wdt_start(struct watchdog_device *wd_dev)
> iTCO_vendor_pre_start(p->smi_res, wd_dev->timeout);
>
> /* disable chipset's NO_REBOOT bit */
> - if (iTCO_wdt_unset_NO_REBOOT_bit(p)) {
> + if (p->update_no_reboot_bit(p, false)) {
> spin_unlock(&p->io_lock);
> pr_err("failed to reset NO_REBOOT flag, reboot disabled by hardware/BIOS\n");
> return -EIO;
> @@ -263,7 +278,7 @@ static int iTCO_wdt_stop(struct watchdog_device *wd_dev)
> val = inw(TCO1_CNT(p));
>
> /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
> - iTCO_wdt_set_NO_REBOOT_bit(p);
> + p->update_no_reboot_bit(p, true);
>
> spin_unlock(&p->io_lock);
>
> @@ -428,6 +443,8 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
> p->iTCO_version = pdata->version;
> p->pci_dev = to_pci_dev(dev->parent);
>
> + iTCO_wdt_no_reboot_bit_setup(p);
> +
> /*
> * Get the Memory-Mapped GCS or PMC register, we need it for the
> * NO_REBOOT flag (TCO v2 and v3).
> @@ -442,14 +459,14 @@ static int iTCO_wdt_probe(struct platform_device *pdev)
> }
>
> /* Check chipset's NO_REBOOT bit */
> - if (iTCO_wdt_unset_NO_REBOOT_bit(p) &&
> + if (p->update_no_reboot_bit(p, false) &&
> iTCO_vendor_check_noreboot_on()) {
> pr_info("unable to reset NO_REBOOT flag, device disabled by hardware/BIOS\n");
> return -ENODEV; /* Cannot reset NO_REBOOT bit */
> }
>
> /* Set the NO_REBOOT bit to prevent later reboots, just for sure */
> - iTCO_wdt_set_NO_REBOOT_bit(p);
> + p->update_no_reboot_bit(p, true);
>
> /* The TCO logic uses the TCO_EN bit in the SMI_EN register */
> if (!devm_request_region(dev, p->smi_res->start,
>
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