On Fri, Mar 19, 2021 at 01:27:41AM CDT, Andrew Jeffery wrote:
>Make the KCS device drivers responsible for allocating their own memory.
>
>Until now the private data for the device driver was allocated internal
>to the private data for the chardev interface. This coupling required
>the slightly awkward API of passing through the struct size for the
>driver private data to the chardev constructor, and then retrieving a
>pointer to the driver private data from the allocated chardev memory.
>
>In addition to being awkward, the arrangement prevents the
>implementation of alternative userspace interfaces as the device driver
>private data is not independent.
>
>Peel a layer off the onion and turn the data-structures inside out by
>exploiting container_of() and embedding `struct kcs_device` in the
>driver private data.
>
>Signed-off-by: Andrew Jeffery <and...@aj.id.au>
>---
> drivers/char/ipmi/kcs_bmc.c           | 15 +++++--
> drivers/char/ipmi/kcs_bmc.h           | 12 ++----
> drivers/char/ipmi/kcs_bmc_aspeed.c    | 60 ++++++++++++++++-----------
> drivers/char/ipmi/kcs_bmc_cdev_ipmi.c | 60 ++++++++++++++++++---------
> drivers/char/ipmi/kcs_bmc_npcm7xx.c   | 37 ++++++++++-------
> 5 files changed, 113 insertions(+), 71 deletions(-)
>
>diff --git a/drivers/char/ipmi/kcs_bmc.c b/drivers/char/ipmi/kcs_bmc.c
>index ef5c48ffe74a..709b6bdec165 100644
>--- a/drivers/char/ipmi/kcs_bmc.c
>+++ b/drivers/char/ipmi/kcs_bmc.c
>@@ -44,12 +44,19 @@ int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc)
> }
> EXPORT_SYMBOL(kcs_bmc_handle_event);
>
>-struct kcs_bmc *kcs_bmc_ipmi_alloc(struct device *dev, int sizeof_priv, u32 
>channel);
>-struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv, u32 
>channel)
>+int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc *kcs_bmc);

Another declaration perhaps intended for kcs_bmc.h?

>+int kcs_bmc_add_device(struct kcs_bmc *kcs_bmc)
> {
>-      return kcs_bmc_ipmi_alloc(dev, sizeof_priv, channel);
>+      return kcs_bmc_ipmi_attach_cdev(kcs_bmc);
> }
>-EXPORT_SYMBOL(kcs_bmc_alloc);
>+EXPORT_SYMBOL(kcs_bmc_add_device);
>+
>+int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc *kcs_bmc);

Here too.

>+int kcs_bmc_remove_device(struct kcs_bmc *kcs_bmc)
>+{
>+      return kcs_bmc_ipmi_detach_cdev(kcs_bmc);
>+}
>+EXPORT_SYMBOL(kcs_bmc_remove_device);
>
> MODULE_LICENSE("GPL v2");
> MODULE_AUTHOR("Haiyue Wang <haiyue.w...@linux.intel.com>");
>diff --git a/drivers/char/ipmi/kcs_bmc.h b/drivers/char/ipmi/kcs_bmc.h
>index febea0c8deb4..bf0ae327997f 100644
>--- a/drivers/char/ipmi/kcs_bmc.h
>+++ b/drivers/char/ipmi/kcs_bmc.h
>@@ -67,6 +67,8 @@ struct kcs_ioreg {
> };
>
> struct kcs_bmc {
>+      struct device *dev;
>+
>       spinlock_t lock;
>
>       u32 channel;
>@@ -94,17 +96,11 @@ struct kcs_bmc {
>       u8 *kbuffer;
>
>       struct miscdevice miscdev;
>-
>-      unsigned long priv[];
> };
>
>-static inline void *kcs_bmc_priv(struct kcs_bmc *kcs_bmc)
>-{
>-      return kcs_bmc->priv;
>-}
>-
> int kcs_bmc_handle_event(struct kcs_bmc *kcs_bmc);
>-struct kcs_bmc *kcs_bmc_alloc(struct device *dev, int sizeof_priv, u32 
>channel);
>+int kcs_bmc_add_device(struct kcs_bmc *kcs_bmc);
>+int kcs_bmc_remove_device(struct kcs_bmc *kcs_bmc);
>
> u8 kcs_bmc_read_data(struct kcs_bmc *kcs_bmc);
> void kcs_bmc_write_data(struct kcs_bmc *kcs_bmc, u8 data);
>diff --git a/drivers/char/ipmi/kcs_bmc_aspeed.c 
>b/drivers/char/ipmi/kcs_bmc_aspeed.c
>index 630cf095560e..0416ac78ce68 100644
>--- a/drivers/char/ipmi/kcs_bmc_aspeed.c
>+++ b/drivers/char/ipmi/kcs_bmc_aspeed.c
>@@ -61,6 +61,8 @@
> #define LPC_STR4             0x11C
>
> struct aspeed_kcs_bmc {
>+      struct kcs_bmc kcs_bmc;
>+
>       struct regmap *map;
> };
>
>@@ -69,9 +71,14 @@ struct aspeed_kcs_of_ops {
>       int (*get_io_address)(struct platform_device *pdev);
> };
>
>+static inline struct aspeed_kcs_bmc *to_aspeed_kcs_bmc(struct kcs_bmc 
>*kcs_bmc)
>+{
>+      return container_of(kcs_bmc, struct aspeed_kcs_bmc, kcs_bmc);
>+}
>+
> static u8 aspeed_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
> {
>-      struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
>+      struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
>       u32 val = 0;
>       int rc;
>
>@@ -83,7 +90,7 @@ static u8 aspeed_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
>
> static void aspeed_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
> {
>-      struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
>+      struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
>       int rc;
>
>       rc = regmap_write(priv->map, reg, data);
>@@ -92,7 +99,7 @@ static void aspeed_kcs_outb(struct kcs_bmc *kcs_bmc, u32 
>reg, u8 data)
>
> static void aspeed_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 
> val)
> {
>-      struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
>+      struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
>       int rc;
>
>       rc = regmap_update_bits(priv->map, reg, mask, val);
>@@ -114,7 +121,7 @@ static void aspeed_kcs_updateb(struct kcs_bmc *kcs_bmc, 
>u32 reg, u8 mask, u8 val
>  */
> static void aspeed_kcs_set_address(struct kcs_bmc *kcs_bmc, u16 addr)
> {
>-      struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
>+      struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
>
>       switch (kcs_bmc->channel) {
>       case 1:
>@@ -148,7 +155,7 @@ static void aspeed_kcs_set_address(struct kcs_bmc 
>*kcs_bmc, u16 addr)
>
> static void aspeed_kcs_enable_channel(struct kcs_bmc *kcs_bmc, bool enable)
> {
>-      struct aspeed_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
>+      struct aspeed_kcs_bmc *priv = to_aspeed_kcs_bmc(kcs_bmc);
>
>       switch (kcs_bmc->channel) {
>       case 1:
>@@ -323,16 +330,16 @@ static int aspeed_kcs_of_v2_get_io_address(struct 
>platform_device *pdev)
> static int aspeed_kcs_probe(struct platform_device *pdev)
> {
>       const struct aspeed_kcs_of_ops *ops;
>-      struct device *dev = &pdev->dev;
>+      struct aspeed_kcs_bmc *priv;
>       struct kcs_bmc *kcs_bmc;
>       struct device_node *np;
>       int rc, channel, addr;
>
>-      np = dev->of_node->parent;
>+      np = pdev->dev.of_node->parent;
>       if (!of_device_is_compatible(np, "aspeed,ast2400-lpc-v2") &&
>           !of_device_is_compatible(np, "aspeed,ast2500-lpc-v2") &&
>           !of_device_is_compatible(np, "aspeed,ast2600-lpc-v2")) {
>-              dev_err(dev, "unsupported LPC device binding\n");
>+              dev_err(&pdev->dev, "unsupported LPC device binding\n");
>               return -ENODEV;
>       }
>       ops = of_device_get_match_data(&pdev->dev);
>@@ -343,18 +350,27 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
>       if (channel < 0)
>               return channel;
>
>-      kcs_bmc = kcs_bmc_alloc(&pdev->dev, sizeof(struct aspeed_kcs_bmc), 
>channel);
>-      if (!kcs_bmc)
>+      addr = ops->get_io_address(pdev);
>+      if (addr < 0)
>+              return addr;
>+
>+      priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
>+      if (!priv)
>               return -ENOMEM;
>
>+      kcs_bmc = &priv->kcs_bmc;
>+      kcs_bmc->dev = &pdev->dev;
>+      kcs_bmc->channel = channel;
>       kcs_bmc->ioreg = ast_kcs_bmc_ioregs[channel - 1];
>       kcs_bmc->io_inputb = aspeed_kcs_inb;
>       kcs_bmc->io_outputb = aspeed_kcs_outb;
>       kcs_bmc->io_updateb = aspeed_kcs_updateb;
>
>-      addr = ops->get_io_address(pdev);
>-      if (addr < 0)
>-              return addr;
>+      priv->map = syscon_node_to_regmap(pdev->dev.parent->of_node);
>+      if (IS_ERR(priv->map)) {
>+              dev_err(&pdev->dev, "Couldn't get regmap\n");
>+              return -ENODEV;
>+      }

The reanimated priv->map initialization I suspect wasn't meant to
have been removed in the first place...

>
>       aspeed_kcs_set_address(kcs_bmc, addr);
>
>@@ -362,29 +378,25 @@ static int aspeed_kcs_probe(struct platform_device *pdev)
>       if (rc)
>               return rc;
>
>-      dev_set_drvdata(dev, kcs_bmc);
>+      platform_set_drvdata(pdev, priv);
>
>       aspeed_kcs_enable_channel(kcs_bmc, true);
>
>-      rc = misc_register(&kcs_bmc->miscdev);
>-      if (rc) {
>-              dev_err(dev, "Unable to register device\n");
>+      rc = kcs_bmc_add_device(&priv->kcs_bmc);
>+      if (rc < 0)
>               return rc;
>-      }
>
>-      dev_dbg(&pdev->dev,
>-              "Probed KCS device %d (IDR=0x%x, ODR=0x%x, STR=0x%x)\n",
>-              kcs_bmc->channel, kcs_bmc->ioreg.idr, kcs_bmc->ioreg.odr,
>-              kcs_bmc->ioreg.str);
>+      dev_info(&pdev->dev, "Initialised channel %d at 0x%x\n", 
>kcs_bmc->channel, addr);

Is the dbg->info change here intentional?  (I have no particular
objection if so, but it's often a change I make myself during
testing/debugging and then forget to revert...)

>
>       return 0;
> }
>
> static int aspeed_kcs_remove(struct platform_device *pdev)
> {
>-      struct kcs_bmc *kcs_bmc = dev_get_drvdata(&pdev->dev);
>+      struct aspeed_kcs_bmc *priv = platform_get_drvdata(pdev);
>+      struct kcs_bmc *kcs_bmc = &priv->kcs_bmc;
>
>-      misc_deregister(&kcs_bmc->miscdev);
>+      kcs_bmc_remove_device(kcs_bmc);

Should we propagate the return value outward here?

>
>       return 0;
> }
>diff --git a/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c 
>b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
>index 82c77994e481..0ca71c135a1a 100644
>--- a/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
>+++ b/drivers/char/ipmi/kcs_bmc_cdev_ipmi.c
>@@ -382,7 +382,7 @@ static int kcs_bmc_ipmi_release(struct inode *inode, 
>struct file *filp)
>       return 0;
> }
>
>-static const struct file_operations kcs_bmc_fops = {
>+static const struct file_operations kcs_bmc_ipmi_fops = {
>       .owner          = THIS_MODULE,
>       .open           = kcs_bmc_ipmi_open,
>       .read           = kcs_bmc_ipmi_read,
>@@ -392,36 +392,58 @@ static const struct file_operations kcs_bmc_fops = {
>       .unlocked_ioctl = kcs_bmc_ipmi_ioctl,
> };
>
>-struct kcs_bmc *kcs_bmc_ipmi_alloc(struct device *dev, int sizeof_priv, u32 
>channel);
>-struct kcs_bmc *kcs_bmc_ipmi_alloc(struct device *dev, int sizeof_priv, u32 
>channel)
>+int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc *kcs_bmc);

Errant declaration again?

>+int kcs_bmc_ipmi_attach_cdev(struct kcs_bmc *kcs_bmc)
> {
>-      struct kcs_bmc *kcs_bmc;
>-
>-      kcs_bmc = devm_kzalloc(dev, sizeof(*kcs_bmc) + sizeof_priv, GFP_KERNEL);
>-      if (!kcs_bmc)
>-              return NULL;
>+      int rc;
>
>       spin_lock_init(&kcs_bmc->lock);
>-      kcs_bmc->channel = channel;
>-
>       mutex_init(&kcs_bmc->mutex);
>       init_waitqueue_head(&kcs_bmc->queue);
>
>-      kcs_bmc->data_in = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
>-      kcs_bmc->data_out = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
>-      kcs_bmc->kbuffer = devm_kmalloc(dev, KCS_MSG_BUFSIZ, GFP_KERNEL);
>+      kcs_bmc->data_in = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, 
>GFP_KERNEL);
>+      kcs_bmc->data_out = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, 
>GFP_KERNEL);
>+      kcs_bmc->kbuffer = devm_kmalloc(kcs_bmc->dev, KCS_MSG_BUFSIZ, 
>GFP_KERNEL);
>
>       kcs_bmc->miscdev.minor = MISC_DYNAMIC_MINOR;
>-      kcs_bmc->miscdev.name = devm_kasprintf(dev, GFP_KERNEL, "%s%u",
>-                                             DEVICE_NAME, channel);
>+      kcs_bmc->miscdev.name = devm_kasprintf(kcs_bmc->dev, GFP_KERNEL, "%s%u",
>+                                             DEVICE_NAME, kcs_bmc->channel);
>       if (!kcs_bmc->data_in || !kcs_bmc->data_out || !kcs_bmc->kbuffer ||
>           !kcs_bmc->miscdev.name)
>-              return NULL;
>-      kcs_bmc->miscdev.fops = &kcs_bmc_fops;
>+              return -ENOMEM;
>
>-      return kcs_bmc;
>+      kcs_bmc->miscdev.fops = &kcs_bmc_ipmi_fops;
>+
>+      rc = misc_register(&kcs_bmc->miscdev);
>+      if (rc) {
>+              dev_err(kcs_bmc->dev, "Unable to register device: %d\n", rc);
>+              return rc;
>+      }
>+
>+      dev_info(kcs_bmc->dev, "Initialised IPMI client for channel %d", 
>kcs_bmc->channel);
>+
>+      return 0;
>+}
>+EXPORT_SYMBOL(kcs_bmc_ipmi_attach_cdev);
>+
>+int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc *kcs_bmc);

Same here.

>+int kcs_bmc_ipmi_detach_cdev(struct kcs_bmc *kcs_bmc)
>+{
>+      misc_deregister(&kcs_bmc->miscdev);
>+
>+      spin_lock_irq(&kcs_bmc->lock);
>+      kcs_bmc->running = 0;
>+      kcs_bmc_ipmi_force_abort(kcs_bmc);
>+      spin_unlock_irq(&kcs_bmc->lock);
>+
>+      devm_kfree(kcs_bmc->dev, kcs_bmc->kbuffer);
>+      devm_kfree(kcs_bmc->dev, kcs_bmc->data_out);
>+      devm_kfree(kcs_bmc->dev, kcs_bmc->data_in);
>+      devm_kfree(kcs_bmc->dev, kcs_bmc);
>+
>+      return 0;
> }
>-EXPORT_SYMBOL(kcs_bmc_ipmi_alloc);
>+EXPORT_SYMBOL(kcs_bmc_ipmi_detach_cdev);
>
> MODULE_LICENSE("GPL v2");
> MODULE_AUTHOR("Haiyue Wang <haiyue.w...@linux.intel.com>");
>diff --git a/drivers/char/ipmi/kcs_bmc_npcm7xx.c 
>b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
>index 1f44aadec9e8..5d017498dc69 100644
>--- a/drivers/char/ipmi/kcs_bmc_npcm7xx.c
>+++ b/drivers/char/ipmi/kcs_bmc_npcm7xx.c
>@@ -65,6 +65,8 @@ struct npcm7xx_kcs_reg {
> };
>
> struct npcm7xx_kcs_bmc {
>+      struct kcs_bmc kcs_bmc;
>+
>       struct regmap *map;
>
>       const struct npcm7xx_kcs_reg *reg;
>@@ -76,9 +78,14 @@ static const struct npcm7xx_kcs_reg 
>npcm7xx_kcs_reg_tbl[KCS_CHANNEL_MAX] = {
>       { .sts = KCS3ST, .dob = KCS3DO, .dib = KCS3DI, .ctl = KCS3CTL, .ie = 
> KCS3IE },
> };
>
>+static inline struct npcm7xx_kcs_bmc *to_npcm7xx_kcs_bmc(struct kcs_bmc 
>*kcs_bmc)
>+{
>+      return container_of(kcs_bmc, struct npcm7xx_kcs_bmc, kcs_bmc);
>+}
>+
> static u8 npcm7xx_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
> {
>-      struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
>+      struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
>       u32 val = 0;
>       int rc;
>
>@@ -90,7 +97,7 @@ static u8 npcm7xx_kcs_inb(struct kcs_bmc *kcs_bmc, u32 reg)
>
> static void npcm7xx_kcs_outb(struct kcs_bmc *kcs_bmc, u32 reg, u8 data)
> {
>-      struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
>+      struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
>       int rc;
>
>       rc = regmap_write(priv->map, reg, data);
>@@ -99,7 +106,7 @@ static void npcm7xx_kcs_outb(struct kcs_bmc *kcs_bmc, u32 
>reg, u8 data)
>
> static void npcm7xx_kcs_updateb(struct kcs_bmc *kcs_bmc, u32 reg, u8 mask, u8 
> data)
> {
>-      struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
>+      struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
>       int rc;
>
>       rc = regmap_update_bits(priv->map, reg, mask, data);
>@@ -108,7 +115,7 @@ static void npcm7xx_kcs_updateb(struct kcs_bmc *kcs_bmc, 
>u32 reg, u8 mask, u8 da
>
> static void npcm7xx_kcs_enable_channel(struct kcs_bmc *kcs_bmc, bool enable)
> {
>-      struct npcm7xx_kcs_bmc *priv = kcs_bmc_priv(kcs_bmc);
>+      struct npcm7xx_kcs_bmc *priv = to_npcm7xx_kcs_bmc(kcs_bmc);
>
>       regmap_update_bits(priv->map, priv->reg->ctl, KCS_CTL_IBFIE,
>                          enable ? KCS_CTL_IBFIE : 0);
>@@ -155,11 +162,10 @@ static int npcm7xx_kcs_probe(struct platform_device 
>*pdev)
>               return -ENODEV;
>       }
>
>-      kcs_bmc = kcs_bmc_alloc(dev, sizeof(*priv), chan);
>-      if (!kcs_bmc)
>+      priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
>+      if (!priv)
>               return -ENOMEM;
>
>-      priv = kcs_bmc_priv(kcs_bmc);
>       priv->map = syscon_node_to_regmap(dev->parent->of_node);
>       if (IS_ERR(priv->map)) {
>               dev_err(dev, "Couldn't get regmap\n");
>@@ -167,6 +173,9 @@ static int npcm7xx_kcs_probe(struct platform_device *pdev)
>       }
>       priv->reg = &npcm7xx_kcs_reg_tbl[chan - 1];
>
>+      kcs_bmc = &priv->kcs_bmc;
>+      kcs_bmc->dev = &pdev->dev;
>+      kcs_bmc->channel = chan;
>       kcs_bmc->ioreg.idr = priv->reg->dib;
>       kcs_bmc->ioreg.odr = priv->reg->dob;
>       kcs_bmc->ioreg.str = priv->reg->sts;
>@@ -174,31 +183,27 @@ static int npcm7xx_kcs_probe(struct platform_device 
>*pdev)
>       kcs_bmc->io_outputb = npcm7xx_kcs_outb;
>       kcs_bmc->io_updateb = npcm7xx_kcs_updateb;
>
>-      dev_set_drvdata(dev, kcs_bmc);
>+      platform_set_drvdata(pdev, priv);
>
>       npcm7xx_kcs_enable_channel(kcs_bmc, true);
>       rc = npcm7xx_kcs_config_irq(kcs_bmc, pdev);
>       if (rc)
>               return rc;
>
>-      rc = misc_register(&kcs_bmc->miscdev);
>-      if (rc) {
>-              dev_err(dev, "Unable to register device\n");
>-              return rc;
>-      }
>
>       pr_info("channel=%u idr=0x%x odr=0x%x str=0x%x\n",
>               chan,
>               kcs_bmc->ioreg.idr, kcs_bmc->ioreg.odr, kcs_bmc->ioreg.str);
>
>-      return 0;
>+      return kcs_bmc_add_device(kcs_bmc);
> }
>
> static int npcm7xx_kcs_remove(struct platform_device *pdev)
> {
>-      struct kcs_bmc *kcs_bmc = dev_get_drvdata(&pdev->dev);
>+      struct npcm7xx_kcs_bmc *priv = platform_get_drvdata(pdev);
>+      struct kcs_bmc *kcs_bmc = &priv->kcs_bmc;
>
>-      misc_deregister(&kcs_bmc->miscdev);
>+      kcs_bmc_remove_device(kcs_bmc);

As with the corresponding aspeed code, should we propagate the return
value here?

>
>       return 0;
> }
>-- 
>2.27.0
>

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