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Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.6.2 Subject: Re: [PATCH 05/21] ata: libahci_platform: Convert to using devm bulk clocks API Content-Language: en-US To: Serge Semin , Hans de Goede , Jens Axboe Cc: Serge Semin , Alexey Malahov , Pavel Parkhomenko , Rob Herring , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org References: <20220324001628.13028-1-Sergey.Semin@baikalelectronics.ru> <20220324001628.13028-6-Sergey.Semin@baikalelectronics.ru> From: Damien Le Moal Organization: Western Digital Research In-Reply-To: <20220324001628.13028-6-Sergey.Semin@baikalelectronics.ru> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/24/22 09:16, Serge Semin wrote: > In order to simplify the clock-related code there is a way to convert the > current fixed clocks array into using the common bulk clocks kernel API > with dynamic set of the clock handlers and device-managed clock-resource > tracking. It's a bit tricky due to the complication coming from the > requirement to support the platforms (da850, spear13xx) with the > non-OF-based clock source, but still doable. > > Before this modification there are two methods have been used to get the > clocks connected to an AHCI device: clk_get() - to get the very first > clock in the list and of_clk_get() - to get the rest of them. Basically > the platforms with non-OF-based clocks definition could specify only a > single reference clock source. The platforms with OF-hw clocks have been > luckier and could setup up to AHCI_MAX_CLKS clocks. Such semantic can be > retained with using devm_clk_bulk_get_all() to retrieve the clocks defined > via the DT firmware and devm_clk_get_optional() otherwise. In both cases > using the device-managed version of the methods will cause the automatic > resources deallocation on the AHCI device removal event. The only > complicated part in the suggested approach is the explicit allocation and > initialization of the clk_bulk_data structure instance for the non-OF > reference clocks. It's required in order to use the Bulk Clocks API for > the both denoted cases of the clocks definition. > > Note aside with the clock-related code reduction and natural > simplification, there are several bonuses the suggested modification > provides. First of all the limitation of having no greater than > AHCI_MAX_CLKS clocks is now removed, since the devm_clk_bulk_get_all() > method will allocate as many reference clocks data descriptors as there > are clocks specified for the device. Secondly the clock names are > auto-detected. So the glue drivers can make sure that the required clocks > are specified just by checking the clock IDs in the clk_bulk_data array. > Thirdly using the handy Bulk Clocks kernel API improves the > clocks-handling code readability. And the last but not least this > modification implements a true optional clocks support to the > ahci_platform_get_resources() method. Indeed the previous clocks getting > procedure just stopped getting the clocks on any errors (aside from > non-critical -EPROBE_DEFER) in a way so the callee wasn't even informed > about abnormal loop termination. The new implementation lacks of such > problem. The ahci_platform_get_resources() will return an error code if > the corresponding clocks getting method ends execution abnormally. > > Signed-off-by: Serge Semin > --- > drivers/ata/ahci.h | 4 +- > drivers/ata/libahci_platform.c | 82 +++++++++++++++------------------- > 2 files changed, 37 insertions(+), 49 deletions(-) > > diff --git a/drivers/ata/ahci.h b/drivers/ata/ahci.h > index eeac5482f1d1..1564c691094a 100644 > --- a/drivers/ata/ahci.h > +++ b/drivers/ata/ahci.h > @@ -38,7 +38,6 @@ > > enum { > AHCI_MAX_PORTS = 32, > - AHCI_MAX_CLKS = 5, > AHCI_MAX_SG = 168, /* hardware max is 64K */ > AHCI_DMA_BOUNDARY = 0xffffffff, > AHCI_MAX_CMDS = 32, > @@ -341,7 +340,8 @@ struct ahci_host_priv { > u32 em_msg_type; /* EM message type */ > u32 remapped_nvme; /* NVMe remapped device count */ > bool got_runtime_pm; /* Did we do pm_runtime_get? */ > - struct clk *clks[AHCI_MAX_CLKS]; /* Optional */ > + unsigned int n_clks; > + struct clk_bulk_data *clks; /* Optional */ > struct reset_control *rsts; /* Optional */ > struct regulator **target_pwrs; /* Optional */ > struct regulator *ahci_regulator;/* Optional */ > diff --git a/drivers/ata/libahci_platform.c b/drivers/ata/libahci_platform.c > index 8eabbb5f208c..d805ddc3a024 100644 > --- a/drivers/ata/libahci_platform.c > +++ b/drivers/ata/libahci_platform.c > @@ -8,6 +8,7 @@ > * Anton Vorontsov > */ > > +#include > #include > #include > #include > @@ -97,28 +98,14 @@ EXPORT_SYMBOL_GPL(ahci_platform_disable_phys); > * ahci_platform_enable_clks - Enable platform clocks > * @hpriv: host private area to store config values > * > - * This function enables all the clks found in hpriv->clks, starting at > - * index 0. If any clk fails to enable it disables all the clks already > - * enabled in reverse order, and then returns an error. > + * This function enables all the clks found for the AHCI device. > * > * RETURNS: > * 0 on success otherwise a negative error code > */ > int ahci_platform_enable_clks(struct ahci_host_priv *hpriv) > { > - int c, rc; > - > - for (c = 0; c < AHCI_MAX_CLKS && hpriv->clks[c]; c++) { > - rc = clk_prepare_enable(hpriv->clks[c]); > - if (rc) > - goto disable_unprepare_clk; > - } > - return 0; > - > -disable_unprepare_clk: > - while (--c >= 0) > - clk_disable_unprepare(hpriv->clks[c]); > - return rc; > + return clk_bulk_prepare_enable(hpriv->n_clks, hpriv->clks); > } > EXPORT_SYMBOL_GPL(ahci_platform_enable_clks); > > @@ -126,16 +113,13 @@ EXPORT_SYMBOL_GPL(ahci_platform_enable_clks); > * ahci_platform_disable_clks - Disable platform clocks > * @hpriv: host private area to store config values > * > - * This function disables all the clks found in hpriv->clks, in reverse > - * order of ahci_platform_enable_clks (starting at the end of the array). > + * This function disables all the clocks enabled before > + * (bulk-clocks-disable function is supposed to do that in reverse > + * from the enabling procedure order). > */ > void ahci_platform_disable_clks(struct ahci_host_priv *hpriv) > { > - int c; > - > - for (c = AHCI_MAX_CLKS - 1; c >= 0; c--) > - if (hpriv->clks[c]) > - clk_disable_unprepare(hpriv->clks[c]); > + clk_bulk_disable_unprepare(hpriv->n_clks, hpriv->clks); > } > EXPORT_SYMBOL_GPL(ahci_platform_disable_clks); > > @@ -292,8 +276,6 @@ static void ahci_platform_put_resources(struct device *dev, void *res) > pm_runtime_disable(dev); > } > > - for (c = 0; c < AHCI_MAX_CLKS && hpriv->clks[c]; c++) > - clk_put(hpriv->clks[c]); > /* > * The regulators are tied to child node device and not to the > * SATA device itself. So we can't use devm for automatically > @@ -374,8 +356,8 @@ static int ahci_platform_get_regulator(struct ahci_host_priv *hpriv, u32 port, > * 1) mmio registers (IORESOURCE_MEM 0, mandatory) > * 2) regulator for controlling the targets power (optional) > * regulator for controlling the AHCI controller (optional) > - * 3) 0 - AHCI_MAX_CLKS clocks, as specified in the devs devicetree node, > - * or for non devicetree enabled platforms a single clock > + * 3) all clocks specified in the devicetree node, or a single > + * clock for non-OF platforms (optional) > * 4) resets, if flags has AHCI_PLATFORM_GET_RESETS (optional) > * 5) phys (optional) > * > @@ -385,11 +367,10 @@ static int ahci_platform_get_regulator(struct ahci_host_priv *hpriv, u32 port, > struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev, > unsigned int flags) > { > + int enabled_ports = 0, rc = 0, child_nodes; > struct device *dev = &pdev->dev; > struct ahci_host_priv *hpriv; > - struct clk *clk; > struct device_node *child; > - int i, enabled_ports = 0, rc = 0, child_nodes; > u32 mask_port_map = 0; > > if (!devres_open_group(dev, NULL, GFP_KERNEL)) > @@ -413,25 +394,32 @@ struct ahci_host_priv *ahci_platform_get_resources(struct platform_device *pdev, > } > } > > - for (i = 0; i < AHCI_MAX_CLKS; i++) { > - /* > - * For now we must use clk_get(dev, NULL) for the first clock, > - * because some platforms (da850, spear13xx) are not yet > - * converted to use devicetree for clocks. For new platforms > - * this is equivalent to of_clk_get(dev->of_node, 0). > - */ > - if (i == 0) > - clk = clk_get(dev, NULL); > - else > - clk = of_clk_get(dev->of_node, i); > - > - if (IS_ERR(clk)) { > - rc = PTR_ERR(clk); > - if (rc == -EPROBE_DEFER) > - goto err_out; > - break; > + /* > + * Bulk clock get procedure can fail to find any clock due to running > + * an a non-OF platform or due to the clocks being defined in bypass > + * from the DT firmware (like da850, spear13xx). In that case we > + * fallback to getting a single clock source right from the dev clocks > + * list. > + */ > + rc = devm_clk_bulk_get_all(dev, &hpriv->clks); I would move the error check first here to make things more readable: rc = devm_clk_bulk_get_all(dev, &hpriv->clks); if (rc < 0) goto err_out; if (rc) { /* Got clocks in bulk */ hpriv->n_clks = rc; } else { /* * No clock bulk found: fallback to manually getting * the optional clock. */ hpriv->clks = devm_kzalloc(dev, sizeof(*hpriv->clks), GFP_KERNEL); ... } And it may be cleaner to move this entire code hunk into a helper, something like ahci_platform_get_clks() ? > + if (rc > 0) { > + hpriv->n_clks = rc; > + } else if (!rc) { > + hpriv->clks = devm_kzalloc(dev, sizeof(*hpriv->clks), GFP_KERNEL); > + if (!hpriv->clks) { > + rc = -ENOMEM; > + goto err_out; > } > - hpriv->clks[i] = clk; > + hpriv->clks->clk = devm_clk_get_optional(dev, NULL); > + if (IS_ERR(hpriv->clks->clk)) { > + rc = PTR_ERR(hpriv->clks->clk); > + goto err_out; > + } else if (hpriv->clks->clk) { > + hpriv->clks->id = __clk_get_name(hpriv->clks->clk); > + hpriv->n_clks = 1; > + } > + } else { > + goto err_out; > } > > hpriv->ahci_regulator = devm_regulator_get(dev, "ahci"); -- Damien Le Moal Western Digital Research