[5/6] can: c_can: prepare to up the message objects number
diff mbox series

Message ID 20210224225246.11346-6-dariobin@libero.it
State New, archived
Headers show
Series
  • can: c_can: add support to 64 messages objects
Related show

Commit Message

Dario Binacchi Feb. 24, 2021, 10:52 p.m. UTC
As pointed by commit c0a9f4d396c9 ("can: c_can: Reduce register access")
the "driver casts the 16 message objects in stone, which is completely
braindead as contemporary hardware has up to 128 message objects".

The patch prepares the module to extend the number of message objects
beyond the 32 currently managed. This was achieved by transforming the
constants used to manage RX/TX messages into variables without changing
the driver policy.

Signed-off-by: Dario Binacchi <dariobin@libero.it>
---

 drivers/net/can/c_can/c_can.c          | 56 +++++++++++++++++---------
 drivers/net/can/c_can/c_can.h          | 23 +++++------
 drivers/net/can/c_can/c_can_platform.c |  2 +-
 3 files changed, 48 insertions(+), 33 deletions(-)

Comments

kernel test robot Feb. 25, 2021, 7:14 a.m. UTC | #1
Hi Dario,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on mkl-can-next/testing]
[also build test ERROR on linux/master net-next/master net/master linus/master next-20210225]
[cannot apply to sparc-next/master v5.11]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch]

url:    https://github.com/0day-ci/linux/commits/Dario-Binacchi/can-c_can-add-support-to-64-messages-objects/20210225-070042
base:   https://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next.git testing
config: x86_64-randconfig-a006-20210225 (attached as .config)
compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project a921aaf789912d981cbb2036bdc91ad7289e1523)
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # install x86_64 cross compiling tool for clang build
        # apt-get install binutils-x86-64-linux-gnu
        # https://github.com/0day-ci/linux/commit/9bbfc6bc12c1d9a2445413bf6e710302f012c1ae
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Dario-Binacchi/can-c_can-add-support-to-64-messages-objects/20210225-070042
        git checkout 9bbfc6bc12c1d9a2445413bf6e710302f012c1ae
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

>> drivers/net/can/c_can/c_can_pci.c:152:24: error: too few arguments to function call, single argument 'msg_obj_num' was not specified
           dev = alloc_c_can_dev();
                 ~~~~~~~~~~~~~~~ ^
   drivers/net/can/c_can/c_can.h:212:20: note: 'alloc_c_can_dev' declared here
   struct net_device *alloc_c_can_dev(int msg_obj_num);
                      ^
   1 error generated.


vim +/msg_obj_num +152 drivers/net/can/c_can/c_can_pci.c

abcd7f750a7e97 Alexander Stein     2014-04-07  113  
3c8ac0f2ad53a9 Bill Pemberton      2012-12-03  114  static int c_can_pci_probe(struct pci_dev *pdev,
5b92da0443c258 Federico Vaga       2012-06-14  115  			   const struct pci_device_id *ent)
5b92da0443c258 Federico Vaga       2012-06-14  116  {
5b92da0443c258 Federico Vaga       2012-06-14  117  	struct c_can_pci_data *c_can_pci_data = (void *)ent->driver_data;
5b92da0443c258 Federico Vaga       2012-06-14  118  	struct c_can_priv *priv;
5b92da0443c258 Federico Vaga       2012-06-14  119  	struct net_device *dev;
5b92da0443c258 Federico Vaga       2012-06-14  120  	void __iomem *addr;
5b92da0443c258 Federico Vaga       2012-06-14  121  	int ret;
5b92da0443c258 Federico Vaga       2012-06-14  122  
5b92da0443c258 Federico Vaga       2012-06-14  123  	ret = pci_enable_device(pdev);
5b92da0443c258 Federico Vaga       2012-06-14  124  	if (ret) {
5b92da0443c258 Federico Vaga       2012-06-14  125  		dev_err(&pdev->dev, "pci_enable_device FAILED\n");
5b92da0443c258 Federico Vaga       2012-06-14  126  		goto out;
5b92da0443c258 Federico Vaga       2012-06-14  127  	}
5b92da0443c258 Federico Vaga       2012-06-14  128  
5b92da0443c258 Federico Vaga       2012-06-14  129  	ret = pci_request_regions(pdev, KBUILD_MODNAME);
5b92da0443c258 Federico Vaga       2012-06-14  130  	if (ret) {
5b92da0443c258 Federico Vaga       2012-06-14  131  		dev_err(&pdev->dev, "pci_request_regions FAILED\n");
5b92da0443c258 Federico Vaga       2012-06-14  132  		goto out_disable_device;
5b92da0443c258 Federico Vaga       2012-06-14  133  	}
5b92da0443c258 Federico Vaga       2012-06-14  134  
78c181bc8a75d3 Wolfgang Grandegger 2014-04-03  135  	ret = pci_enable_msi(pdev);
78c181bc8a75d3 Wolfgang Grandegger 2014-04-03  136  	if (!ret) {
78c181bc8a75d3 Wolfgang Grandegger 2014-04-03  137  		dev_info(&pdev->dev, "MSI enabled\n");
5b92da0443c258 Federico Vaga       2012-06-14  138  		pci_set_master(pdev);
78c181bc8a75d3 Wolfgang Grandegger 2014-04-03  139  	}
5b92da0443c258 Federico Vaga       2012-06-14  140  
abcd7f750a7e97 Alexander Stein     2014-04-07  141  	addr = pci_iomap(pdev, c_can_pci_data->bar,
abcd7f750a7e97 Alexander Stein     2014-04-07  142  			 pci_resource_len(pdev, c_can_pci_data->bar));
5b92da0443c258 Federico Vaga       2012-06-14  143  	if (!addr) {
5b92da0443c258 Federico Vaga       2012-06-14  144  		dev_err(&pdev->dev,
5b92da0443c258 Federico Vaga       2012-06-14  145  			"device has no PCI memory resources, "
5b92da0443c258 Federico Vaga       2012-06-14  146  			"failing adapter\n");
5b92da0443c258 Federico Vaga       2012-06-14  147  		ret = -ENOMEM;
5b92da0443c258 Federico Vaga       2012-06-14  148  		goto out_release_regions;
5b92da0443c258 Federico Vaga       2012-06-14  149  	}
5b92da0443c258 Federico Vaga       2012-06-14  150  
5b92da0443c258 Federico Vaga       2012-06-14  151  	/* allocate the c_can device */
5b92da0443c258 Federico Vaga       2012-06-14 @152  	dev = alloc_c_can_dev();
5b92da0443c258 Federico Vaga       2012-06-14  153  	if (!dev) {
5b92da0443c258 Federico Vaga       2012-06-14  154  		ret = -ENOMEM;
5b92da0443c258 Federico Vaga       2012-06-14  155  		goto out_iounmap;
5b92da0443c258 Federico Vaga       2012-06-14  156  	}
5b92da0443c258 Federico Vaga       2012-06-14  157  
5b92da0443c258 Federico Vaga       2012-06-14  158  	priv = netdev_priv(dev);
5b92da0443c258 Federico Vaga       2012-06-14  159  	pci_set_drvdata(pdev, dev);
5b92da0443c258 Federico Vaga       2012-06-14  160  	SET_NETDEV_DEV(dev, &pdev->dev);
5b92da0443c258 Federico Vaga       2012-06-14  161  
5b92da0443c258 Federico Vaga       2012-06-14  162  	dev->irq = pdev->irq;
5b92da0443c258 Federico Vaga       2012-06-14  163  	priv->base = addr;
c97c52be78b846 Einar Jón           2016-08-12  164  	priv->device = &pdev->dev;
5b92da0443c258 Federico Vaga       2012-06-14  165  
5b92da0443c258 Federico Vaga       2012-06-14  166  	if (!c_can_pci_data->freq) {
1aa2d1daf067c8 Marc Kleine-Budde   2012-06-20  167  		dev_err(&pdev->dev, "no clock frequency defined\n");
5b92da0443c258 Federico Vaga       2012-06-14  168  		ret = -ENODEV;
5b92da0443c258 Federico Vaga       2012-06-14  169  		goto out_free_c_can;
5b92da0443c258 Federico Vaga       2012-06-14  170  	} else {
5b92da0443c258 Federico Vaga       2012-06-14  171  		priv->can.clock.freq = c_can_pci_data->freq;
5b92da0443c258 Federico Vaga       2012-06-14  172  	}
5b92da0443c258 Federico Vaga       2012-06-14  173  
5b92da0443c258 Federico Vaga       2012-06-14  174  	/* Configure CAN type */
5b92da0443c258 Federico Vaga       2012-06-14  175  	switch (c_can_pci_data->type) {
f27b1db95d047d AnilKumar Ch        2012-08-02  176  	case BOSCH_C_CAN:
5b92da0443c258 Federico Vaga       2012-06-14  177  		priv->regs = reg_map_c_can;
5b92da0443c258 Federico Vaga       2012-06-14  178  		break;
f27b1db95d047d AnilKumar Ch        2012-08-02  179  	case BOSCH_D_CAN:
5b92da0443c258 Federico Vaga       2012-06-14  180  		priv->regs = reg_map_d_can;
5b92da0443c258 Federico Vaga       2012-06-14  181  		break;
5b92da0443c258 Federico Vaga       2012-06-14  182  	default:
5b92da0443c258 Federico Vaga       2012-06-14  183  		ret = -EINVAL;
1aa2d1daf067c8 Marc Kleine-Budde   2012-06-20  184  		goto out_free_c_can;
5b92da0443c258 Federico Vaga       2012-06-14  185  	}
5b92da0443c258 Federico Vaga       2012-06-14  186  
129eef2184218f Thomas Gleixner     2014-04-11  187  	priv->type = c_can_pci_data->type;
129eef2184218f Thomas Gleixner     2014-04-11  188  
5b92da0443c258 Federico Vaga       2012-06-14  189  	/* Configure access to registers */
5b92da0443c258 Federico Vaga       2012-06-14  190  	switch (c_can_pci_data->reg_align) {
5b92da0443c258 Federico Vaga       2012-06-14  191  	case C_CAN_REG_ALIGN_32:
5b92da0443c258 Federico Vaga       2012-06-14  192  		priv->read_reg = c_can_pci_read_reg_aligned_to_32bit;
5b92da0443c258 Federico Vaga       2012-06-14  193  		priv->write_reg = c_can_pci_write_reg_aligned_to_32bit;
5b92da0443c258 Federico Vaga       2012-06-14  194  		break;
5b92da0443c258 Federico Vaga       2012-06-14  195  	case C_CAN_REG_ALIGN_16:
5b92da0443c258 Federico Vaga       2012-06-14  196  		priv->read_reg = c_can_pci_read_reg_aligned_to_16bit;
5b92da0443c258 Federico Vaga       2012-06-14  197  		priv->write_reg = c_can_pci_write_reg_aligned_to_16bit;
5b92da0443c258 Federico Vaga       2012-06-14  198  		break;
abcd7f750a7e97 Alexander Stein     2014-04-07  199  	case C_CAN_REG_32:
abcd7f750a7e97 Alexander Stein     2014-04-07  200  		priv->read_reg = c_can_pci_read_reg_32bit;
abcd7f750a7e97 Alexander Stein     2014-04-07  201  		priv->write_reg = c_can_pci_write_reg_32bit;
abcd7f750a7e97 Alexander Stein     2014-04-07  202  		break;
5b92da0443c258 Federico Vaga       2012-06-14  203  	default:
5b92da0443c258 Federico Vaga       2012-06-14  204  		ret = -EINVAL;
1aa2d1daf067c8 Marc Kleine-Budde   2012-06-20  205  		goto out_free_c_can;
5b92da0443c258 Federico Vaga       2012-06-14  206  	}
ccbc5357db3098 Pavel Machek        2014-05-06  207  	priv->read_reg32 = c_can_pci_read_reg32;
ccbc5357db3098 Pavel Machek        2014-05-06  208  	priv->write_reg32 = c_can_pci_write_reg32;
5b92da0443c258 Federico Vaga       2012-06-14  209  
abcd7f750a7e97 Alexander Stein     2014-04-07  210  	priv->raminit = c_can_pci_data->init;
abcd7f750a7e97 Alexander Stein     2014-04-07  211  
5b92da0443c258 Federico Vaga       2012-06-14  212  	ret = register_c_can_dev(dev);
5b92da0443c258 Federico Vaga       2012-06-14  213  	if (ret) {
5b92da0443c258 Federico Vaga       2012-06-14  214  		dev_err(&pdev->dev, "registering %s failed (err=%d)\n",
5b92da0443c258 Federico Vaga       2012-06-14  215  			KBUILD_MODNAME, ret);
1aa2d1daf067c8 Marc Kleine-Budde   2012-06-20  216  		goto out_free_c_can;
5b92da0443c258 Federico Vaga       2012-06-14  217  	}
5b92da0443c258 Federico Vaga       2012-06-14  218  
5b92da0443c258 Federico Vaga       2012-06-14  219  	dev_dbg(&pdev->dev, "%s device registered (regs=%p, irq=%d)\n",
5b92da0443c258 Federico Vaga       2012-06-14  220  		 KBUILD_MODNAME, priv->regs, dev->irq);
5b92da0443c258 Federico Vaga       2012-06-14  221  
5b92da0443c258 Federico Vaga       2012-06-14  222  	return 0;
5b92da0443c258 Federico Vaga       2012-06-14  223  
5b92da0443c258 Federico Vaga       2012-06-14  224  out_free_c_can:
5b92da0443c258 Federico Vaga       2012-06-14  225  	free_c_can_dev(dev);
5b92da0443c258 Federico Vaga       2012-06-14  226  out_iounmap:
5b92da0443c258 Federico Vaga       2012-06-14  227  	pci_iounmap(pdev, addr);
5b92da0443c258 Federico Vaga       2012-06-14  228  out_release_regions:
5b92da0443c258 Federico Vaga       2012-06-14  229  	pci_disable_msi(pdev);
5b92da0443c258 Federico Vaga       2012-06-14  230  	pci_clear_master(pdev);
5b92da0443c258 Federico Vaga       2012-06-14  231  	pci_release_regions(pdev);
5b92da0443c258 Federico Vaga       2012-06-14  232  out_disable_device:
5b92da0443c258 Federico Vaga       2012-06-14  233  	pci_disable_device(pdev);
5b92da0443c258 Federico Vaga       2012-06-14  234  out:
5b92da0443c258 Federico Vaga       2012-06-14  235  	return ret;
5b92da0443c258 Federico Vaga       2012-06-14  236  }
5b92da0443c258 Federico Vaga       2012-06-14  237  

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Marc Kleine-Budde Feb. 25, 2021, 7:23 a.m. UTC | #2
Hey Dario,

just a quick note...

On 24.02.2021 23:52:45, Dario Binacchi wrote:
> -struct net_device *alloc_c_can_dev(void)
> +struct net_device *alloc_c_can_dev(int msg_obj_num)
>  {
>  	struct net_device *dev;
>  	struct c_can_priv *priv;
> +	int msg_obj_tx_num = msg_obj_num / 2;
>  
> -	dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM);
> +	dev = alloc_candev(sizeof(struct c_can_priv), msg_obj_tx_num);
>  	if (!dev)
>  		return NULL;
>  
>  	priv = netdev_priv(dev);
> -	netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
> +	priv->msg_obj_num = msg_obj_num;
> +	priv->msg_obj_rx_num = msg_obj_num - msg_obj_tx_num;
> +	priv->msg_obj_rx_first = 1;
> +	priv->msg_obj_rx_last =
> +		priv->msg_obj_rx_first + priv->msg_obj_rx_num - 1;
> +	priv->msg_obj_rx_mask = ((u64)1 << priv->msg_obj_rx_num) - 1;
> +
> +	priv->msg_obj_tx_num = msg_obj_tx_num;
> +	priv->msg_obj_tx_first = priv->msg_obj_rx_last + 1;
> +	priv->msg_obj_tx_last =
> +		priv->msg_obj_tx_first + priv->msg_obj_tx_num - 1;
> +
> +	priv->dlc = kcalloc(msg_obj_tx_num, sizeof(*priv->dlc), GFP_KERNEL);

You can pass a larger size to alloc_candev() so that it includes the mem
you allocate here.

> +	if (!priv->dlc) {
> +		free_candev(dev);
> +		return NULL;
> +	}
> +
> +	netif_napi_add(dev, &priv->napi, c_can_poll, priv->msg_obj_rx_num);

Marc
Marc Kleine-Budde Feb. 25, 2021, 9:25 a.m. UTC | #3
On 25.02.2021 15:14:43, kernel test robot wrote:
> Hi Dario,
> 
> Thank you for the patch! Yet something to improve:
> 
> [auto build test ERROR on mkl-can-next/testing]
> [also build test ERROR on linux/master net-next/master net/master linus/master next-20210225]
> [cannot apply to sparc-next/master v5.11]
> [If your patch is applied to the wrong git tree, kindly drop us a note.
> And when submitting patch, we suggest to use '--base' as documented in
> https://git-scm.com/docs/git-format-patch]
> 
> url:    https://github.com/0day-ci/linux/commits/Dario-Binacchi/can-c_can-add-support-to-64-messages-objects/20210225-070042
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can-next.git testing
> config: x86_64-randconfig-a006-20210225 (attached as .config)
> compiler: clang version 13.0.0 (https://github.com/llvm/llvm-project a921aaf789912d981cbb2036bdc91ad7289e1523)
> reproduce (this is a W=1 build):
>         wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
>         chmod +x ~/bin/make.cross
>         # install x86_64 cross compiling tool for clang build
>         # apt-get install binutils-x86-64-linux-gnu
>         # https://github.com/0day-ci/linux/commit/9bbfc6bc12c1d9a2445413bf6e710302f012c1ae
>         git remote add linux-review https://github.com/0day-ci/linux
>         git fetch --no-tags linux-review Dario-Binacchi/can-c_can-add-support-to-64-messages-objects/20210225-070042
>         git checkout 9bbfc6bc12c1d9a2445413bf6e710302f012c1ae
>         # save the attached .config to linux build tree
>         COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 
> 
> If you fix the issue, kindly add following tag as appropriate
> Reported-by: kernel test robot <lkp@intel.com>
> 
> All errors (new ones prefixed by >>):
> 
> >> drivers/net/can/c_can/c_can_pci.c:152:24: error: too few arguments to function call, single argument 'msg_obj_num' was not specified
>            dev = alloc_c_can_dev();
>                  ~~~~~~~~~~~~~~~ ^
>    drivers/net/can/c_can/c_can.h:212:20: note: 'alloc_c_can_dev' declared here
>    struct net_device *alloc_c_can_dev(int msg_obj_num);
>                       ^
>    1 error generated.

For now you can use 16, which means no change. I've added Alexander
and Federico to Cc, they added the intel pch and st micro support, maybe
they can help and add the correct size.

regards,
Marc

Patch
diff mbox series

diff --git a/drivers/net/can/c_can/c_can.c b/drivers/net/can/c_can/c_can.c
index 7081cfaf62e2..772b26685fea 100644
--- a/drivers/net/can/c_can/c_can.c
+++ b/drivers/net/can/c_can/c_can.c
@@ -173,9 +173,6 @@ 
 /* Wait for ~1 sec for INIT bit */
 #define INIT_WAIT_MS		1000
 
-/* napi related */
-#define C_CAN_NAPI_WEIGHT	C_CAN_MSG_OBJ_RX_NUM
-
 /* c_can lec values */
 enum c_can_lec_type {
 	LEC_NO_ERROR = 0,
@@ -325,7 +322,7 @@  static void c_can_setup_tx_object(struct net_device *dev, int iface,
 	 * first, i.e. clear the MSGVAL flag in the arbiter.
 	 */
 	if (rtr != (bool)test_bit(idx, &priv->tx_dir)) {
-		u32 obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
+		u32 obj = idx + priv->msg_obj_tx_first;
 
 		c_can_inval_msg_object(dev, iface, obj);
 		change_bit(idx, &priv->tx_dir);
@@ -463,10 +460,10 @@  static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
 	 * prioritized. The lowest buffer number wins.
 	 */
 	idx = fls(atomic_read(&priv->tx_active));
-	obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
+	obj = idx + priv->msg_obj_tx_first;
 
 	/* If this is the last buffer, stop the xmit queue */
-	if (idx == C_CAN_MSG_OBJ_TX_NUM - 1)
+	if (idx == priv->msg_obj_tx_num - 1)
 		netif_stop_queue(dev);
 	/*
 	 * Store the message in the interface so we can call
@@ -549,17 +546,18 @@  static int c_can_set_bittiming(struct net_device *dev)
  */
 static void c_can_configure_msg_objects(struct net_device *dev)
 {
+	struct c_can_priv *priv = netdev_priv(dev);
 	int i;
 
 	/* first invalidate all message objects */
-	for (i = C_CAN_MSG_OBJ_RX_FIRST; i <= C_CAN_NO_OF_OBJECTS; i++)
+	for (i = priv->msg_obj_rx_first; i <= priv->msg_obj_num; i++)
 		c_can_inval_msg_object(dev, IF_RX, i);
 
 	/* setup receive message objects */
-	for (i = C_CAN_MSG_OBJ_RX_FIRST; i < C_CAN_MSG_OBJ_RX_LAST; i++)
+	for (i = priv->msg_obj_rx_first; i < priv->msg_obj_rx_last; i++)
 		c_can_setup_receive_object(dev, IF_RX, i, 0, 0, IF_MCONT_RCV);
 
-	c_can_setup_receive_object(dev, IF_RX, C_CAN_MSG_OBJ_RX_LAST, 0, 0,
+	c_can_setup_receive_object(dev, IF_RX, priv->msg_obj_rx_last, 0, 0,
 				   IF_MCONT_RCV_EOB);
 }
 
@@ -730,7 +728,7 @@  static void c_can_do_tx(struct net_device *dev)
 	while ((idx = ffs(pend))) {
 		idx--;
 		pend &= ~(1 << idx);
-		obj = idx + C_CAN_MSG_OBJ_TX_FIRST;
+		obj = idx + priv->msg_obj_tx_first;
 		c_can_inval_tx_object(dev, IF_TX, obj);
 		can_get_echo_skb(dev, idx, NULL);
 		bytes += priv->dlc[idx];
@@ -740,7 +738,7 @@  static void c_can_do_tx(struct net_device *dev)
 	/* Clear the bits in the tx_active mask */
 	atomic_sub(clr, &priv->tx_active);
 
-	if (clr & (1 << (C_CAN_MSG_OBJ_TX_NUM - 1)))
+	if (clr & (1 << (priv->msg_obj_tx_num - 1)))
 		netif_wake_queue(dev);
 
 	if (pkts) {
@@ -755,11 +753,11 @@  static void c_can_do_tx(struct net_device *dev)
  * raced with the hardware or failed to readout all upper
  * objects in the last run due to quota limit.
  */
-static u32 c_can_adjust_pending(u32 pend)
+static u32 c_can_adjust_pending(u32 pend, u32 rx_mask)
 {
 	u32 weight, lasts;
 
-	if (pend == RECEIVE_OBJECT_BITS)
+	if (pend == rx_mask)
 		return pend;
 
 	/*
@@ -862,8 +860,7 @@  static int c_can_do_rx_poll(struct net_device *dev, int quota)
 	 * It is faster to read only one 16bit register. This is only possible
 	 * for a maximum number of 16 objects.
 	 */
-	BUILD_BUG_ON_MSG(C_CAN_MSG_OBJ_RX_LAST > 16,
-			"Implementation does not support more message objects than 16");
+	WARN_ON(priv->msg_obj_rx_last > 16);
 
 	while (quota > 0) {
 		if (!pend) {
@@ -874,7 +871,8 @@  static int c_can_do_rx_poll(struct net_device *dev, int quota)
 			 * If the pending field has a gap, handle the
 			 * bits above the gap first.
 			 */
-			toread = c_can_adjust_pending(pend);
+			toread = c_can_adjust_pending(pend,
+						      priv->msg_obj_rx_mask);
 		} else {
 			toread = pend;
 		}
@@ -1205,17 +1203,36 @@  static int c_can_close(struct net_device *dev)
 	return 0;
 }
 
-struct net_device *alloc_c_can_dev(void)
+struct net_device *alloc_c_can_dev(int msg_obj_num)
 {
 	struct net_device *dev;
 	struct c_can_priv *priv;
+	int msg_obj_tx_num = msg_obj_num / 2;
 
-	dev = alloc_candev(sizeof(struct c_can_priv), C_CAN_MSG_OBJ_TX_NUM);
+	dev = alloc_candev(sizeof(struct c_can_priv), msg_obj_tx_num);
 	if (!dev)
 		return NULL;
 
 	priv = netdev_priv(dev);
-	netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
+	priv->msg_obj_num = msg_obj_num;
+	priv->msg_obj_rx_num = msg_obj_num - msg_obj_tx_num;
+	priv->msg_obj_rx_first = 1;
+	priv->msg_obj_rx_last =
+		priv->msg_obj_rx_first + priv->msg_obj_rx_num - 1;
+	priv->msg_obj_rx_mask = ((u64)1 << priv->msg_obj_rx_num) - 1;
+
+	priv->msg_obj_tx_num = msg_obj_tx_num;
+	priv->msg_obj_tx_first = priv->msg_obj_rx_last + 1;
+	priv->msg_obj_tx_last =
+		priv->msg_obj_tx_first + priv->msg_obj_tx_num - 1;
+
+	priv->dlc = kcalloc(msg_obj_tx_num, sizeof(*priv->dlc), GFP_KERNEL);
+	if (!priv->dlc) {
+		free_candev(dev);
+		return NULL;
+	}
+
+	netif_napi_add(dev, &priv->napi, c_can_poll, priv->msg_obj_rx_num);
 
 	priv->dev = dev;
 	priv->can.bittiming_const = &c_can_bittiming_const;
@@ -1320,6 +1337,7 @@  void free_c_can_dev(struct net_device *dev)
 	struct c_can_priv *priv = netdev_priv(dev);
 
 	netif_napi_del(&priv->napi);
+	kfree(priv->dlc);
 	free_candev(dev);
 }
 EXPORT_SYMBOL_GPL(free_c_can_dev);
diff --git a/drivers/net/can/c_can/c_can.h b/drivers/net/can/c_can/c_can.h
index 90d3d2e7a086..1dbe777320f5 100644
--- a/drivers/net/can/c_can/c_can.h
+++ b/drivers/net/can/c_can/c_can.h
@@ -22,18 +22,7 @@ 
 #ifndef C_CAN_H
 #define C_CAN_H
 
-/* message object split */
 #define C_CAN_NO_OF_OBJECTS	32
-#define C_CAN_MSG_OBJ_RX_NUM	16
-#define C_CAN_MSG_OBJ_TX_NUM	16
-
-#define C_CAN_MSG_OBJ_RX_FIRST	1
-#define C_CAN_MSG_OBJ_RX_LAST	(C_CAN_MSG_OBJ_RX_FIRST + \
-				C_CAN_MSG_OBJ_RX_NUM - 1)
-
-#define C_CAN_MSG_OBJ_TX_FIRST	(C_CAN_MSG_OBJ_RX_LAST + 1)
-
-#define RECEIVE_OBJECT_BITS	0x0000ffff
 
 enum reg {
 	C_CAN_CTRL_REG = 0,
@@ -193,6 +182,14 @@  struct c_can_priv {
 	struct napi_struct napi;
 	struct net_device *dev;
 	struct device *device;
+	int msg_obj_num;
+	int msg_obj_rx_num;
+	int msg_obj_tx_num;
+	int msg_obj_rx_first;
+	int msg_obj_rx_last;
+	int msg_obj_tx_first;
+	int msg_obj_tx_last;
+	u32 msg_obj_rx_mask;
 	atomic_t tx_active;
 	atomic_t sie_pending;
 	unsigned long tx_dir;
@@ -209,10 +206,10 @@  struct c_can_priv {
 	void (*raminit) (const struct c_can_priv *priv, bool enable);
 	u32 comm_rcv_high;
 	u32 rxmasked;
-	u32 dlc[C_CAN_MSG_OBJ_TX_NUM];
+	u32 *dlc;
 };
 
-struct net_device *alloc_c_can_dev(void);
+struct net_device *alloc_c_can_dev(int msg_obj_num);
 void free_c_can_dev(struct net_device *dev);
 int register_c_can_dev(struct net_device *dev);
 void unregister_c_can_dev(struct net_device *dev);
diff --git a/drivers/net/can/c_can/c_can_platform.c b/drivers/net/can/c_can/c_can_platform.c
index 05f425ceb53a..a5b9b1a93702 100644
--- a/drivers/net/can/c_can/c_can_platform.c
+++ b/drivers/net/can/c_can/c_can_platform.c
@@ -293,7 +293,7 @@  static int c_can_plat_probe(struct platform_device *pdev)
 	}
 
 	/* allocate the c_can device */
-	dev = alloc_c_can_dev();
+	dev = alloc_c_can_dev(C_CAN_NO_OF_OBJECTS);
 	if (!dev) {
 		ret = -ENOMEM;
 		goto exit;