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Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <1546425895.3457.1.camel@pengutronix.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Philipp, On 1/2/19 2:44 AM, Philipp Zabel wrote: > Hi Florian, > > On Thu, 2018-12-20 at 17:34 -0800, Florian Fainelli wrote: >> Add support for resetting blocks through the Linux reset controller >> subsystem when reset lines are provided through a SW_INIT-style reset >> controller on Broadcom STB SoCs. >> >> Signed-off-by: Florian Fainelli > > Thank you, this looks mostly good to me. I just have a few small > nitpicks and I'm curious about the mdelays, see below. Thanks, answers inline. [snip] >> +struct brcmstb_reset { >> + void __iomem *base; > >> + unsigned int n_words; >> + struct device *dev; > > These two variables are not used anywhere. Indeed, the first one should actually be added as a check to make sure we have a correct resource size being passed, I will add that back in. > >> + struct reset_controller_dev rcdev; >> +}; >> + >> +#define SW_INIT_SET 0x00 >> +#define SW_INIT_CLEAR 0x04 >> +#define SW_INIT_STATUS 0x08 >> + >> +#define SW_INIT_BIT(id) BIT((id) & 0x1f) >> +#define SW_INIT_BANK(id) (id >> 5) > > Checkpatch suggests to use ((id) >> 5) here. > >> + >> +#define SW_INIT_BANK_SIZE 0x18 >> + >> +static inline >> +struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev) >> +{ >> + return container_of(rcdev, struct brcmstb_reset, rcdev); >> +} >> + >> +static int brcmstb_reset_assert(struct reset_controller_dev *rcdev, >> + unsigned long id) >> +{ >> + unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; >> + struct brcmstb_reset *priv = to_brcmstb(rcdev); >> + >> + writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_SET); >> + msleep(10); > > What is the purpose of the msleep(10)? Is it guaranteed that the writel > takes effect before the msleep, or could it be lingering in some store > buffer for (a part of) the duration? Also, checkpatch warns about this > being < 20 ms. You could increase the delay or use usleep_range. Good point, let me check what the real delay requirements are with the design team, since I suspect they were just overly conservative in their recommendations previously > >> + return 0; >> +} >> + >> +static int brcmstb_reset_deassert(struct reset_controller_dev *rcdev, >> + unsigned long id) >> +{ >> + unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; >> + struct brcmstb_reset *priv = to_brcmstb(rcdev); >> + >> + writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_CLEAR); >> + msleep(10); > > Same as above, what has to be delayed for 10 ms after deasserting the > reset? Is this the same for all reset lines handled by this controller? AFAICT, all lines behave the same way, as per our SoCs reset architecture. > >> + >> + return 0; >> +} >> + >> +static int brcmstb_reset_status(struct reset_controller_dev *rcdev, >> + unsigned long id) >> +{ >> + unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE; >> + struct brcmstb_reset *priv = to_brcmstb(rcdev); >> + >> + return readl_relaxed(priv->base + off + SW_INIT_STATUS); > > Should this be > > + return readl_relaxed(priv->base + off + SW_INIT_STATUS) & > + SW_INIT_BANK(id); > > i.e. do the SW_INIT_STATUS registers contain 32 status bits, one for > each reset line? Yes they do. The same bits are used for SET/CLEAR/STATUS so this should be something along the lines of: return readl_relaxed(priv->base + off + SW_INIT_STATUS) & BIT(id)); thanks for spotting that! > >> +} >> + >> +static const struct reset_control_ops brcmstb_reset_ops = { >> + .assert = brcmstb_reset_assert, >> + .deassert = brcmstb_reset_deassert, >> + .status = brcmstb_reset_status, >> +}; >> + >> +static int brcmstb_reset_probe(struct platform_device *pdev) >> +{ >> + struct device *kdev = &pdev->dev; >> + struct brcmstb_reset *priv; >> + struct resource *res; >> + >> + priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL); >> + if (!priv) >> + return -ENOMEM; >> + >> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> + priv->base = devm_ioremap_resource(kdev, res); >> + if (IS_ERR(priv->base)) >> + return PTR_ERR(priv->base); >> + >> + dev_set_drvdata(kdev, priv); >> + >> + priv->rcdev.owner = THIS_MODULE; >> + priv->rcdev.nr_resets = (resource_size(res) / SW_INIT_BANK_SIZE) * 32; >> + priv->rcdev.ops = &brcmstb_reset_ops; >> + priv->rcdev.of_node = kdev->of_node; >> + /* Use defaults: 1 cell and simple xlate function */ >> + priv->dev = kdev; > > priv->dev could be removed. Indeed, I had sprinkled dev_*() messages during debug, which required it, but this is no longer required indeed. -- Florian