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SubjectRe: [PATCH 08/12] fsl/fman: Add Frame Manager support
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Date
You should note that I started with scanning this patch for basic, say,
build system issues. Which I did find. But then I kept spotting all kind
of oddities. After a while I stopped looking closely. So, to note
something, I haven't yet looked into the 24 symbols this series exports.
There might be a reason for all 24 of them, but I just thought it a bit
suspect.

But, anyhow, my guess is this series needs a close look or two before
the people understanding ethernet drivers (I'm not one of them) will
consider reviewing it for more substantial issues.

On Wed, 2015-06-10 at 18:21 +0300, Madalin Bucur wrote:
> --- a/drivers/net/ethernet/freescale/fman/Kconfig
> +++ b/drivers/net/ethernet/freescale/fman/Kconfig

> +if FSL_FMAN
> +
> +config FSL_FM_MAX_FRAME_SIZE
> + int "Maximum L2 frame size"
> + depends on FSL_FMAN

This dependency is already provided through "if FSL_MAN" above.

> + range 64 9600
> + default "1522"
> + help
> + Configure this in relation to the maximum possible MTU of your
> + network configuration. In particular, one would need to
> + increase this value in order to use jumbo frames.
> + FSL_FM_MAX_FRAME_SIZE must accommodate the Ethernet FCS
> + (4 bytes) and one ETH+VLAN header (18 bytes), to a total of
> + 22 bytes in excess of the desired L3 MTU.
> +
> + Note that having too large a FSL_FM_MAX_FRAME_SIZE (much larger
> + than the actual MTU) may lead to buffer exhaustion, especially
> + in the case of badly fragmented datagrams on the Rx path.
> + Conversely, having a FSL_FM_MAX_FRAME_SIZE smaller than the
> + actual MTU will lead to frames being dropped.
> +
> +config FSL_FM_RX_EXTRA_HEADROOM
> + int "Add extra headroom at beginning of data buffers"
> + depends on FSL_FMAN

Ditto.

> + range 16 384
> + default "64"
> + help
> + Configure this to tell the Frame Manager to reserve some extra
> + space at the beginning of a data buffer on the receive path,
> + before Internal Context fields are copied. This is in addition
> + to the private data area already reserved for driver internal
> + use. The provided value must be a multiple of 16.
> +
> + This option does not affect in any way the layout of
> + transmitted buffers.
> +
> +endif # FSL_FMAN

> --- a/drivers/net/ethernet/freescale/fman/Makefile
> +++ b/drivers/net/ethernet/freescale/fman/Makefile
>
> obj-y += fsl_fman.o
>
> -fsl_fman-objs := fman.o fm_muram.o
> +fsl_fman-objs := fman.o fm_muram.o fm.o fm_drv.o

> --- /dev/null
> +++ b/drivers/net/ethernet/freescale/fman/fm.c

> +/* static functions */

There's no need to tell us that.

> +static int check_fm_parameters(struct fm_t *p_fm)
> +{

> +#ifdef FM_AID_MODE_NO_TNUM_SW005

I think this is always defined (I already deleted that part of the
patch, so perhaps I'm missing some subtle issue).

> + if (p_fm->p_fm_state_struct->rev_info.major_rev >= 6 &&
> + p_fm->p_fm_drv_param->dma_aid_mode !=
> + E_FMAN_DMA_AID_OUT_PORT_ID) {
> + pr_err("dma_aid_mode not supported by this integration.\n");
> + return -EDOM;
> + }
> +#endif /* FM_AID_MODE_NO_TNUM_SW005 */

> +#ifdef FM_HAS_TOTAL_DMAS

Ditto.

> + if ((p_fm->p_fm_state_struct->rev_info.major_rev < 6) &&
> + (!p_fm->p_fm_state_struct->max_num_of_open_dmas ||
> + (p_fm->p_fm_state_struct->max_num_of_open_dmas >
> + p_fm->intg->bmi_max_num_of_dmas))) {
> + pr_err("max_num_of_open_dmas number has to be in the range 1 - %d\n",
> + p_fm->intg->bmi_max_num_of_dmas);
> + return -EDOM;
> + }
> +#endif /* FM_HAS_TOTAL_DMAS */

> +#ifdef FM_NO_WATCHDOG

Ditto. I'll stop checking for this stuff now. Please clean them up (or
show me that I'm wrong).

> + if ((p_fm->p_fm_state_struct->rev_info.major_rev == 2) &&
> + (p_fm->p_fm_drv_param->dma_watchdog)) {
> + pr_err("watchdog!\n");
> + return -EINVAL;
> + }
> +#endif /* FM_NO_WATCHDOG */

> +/* fm_init
> + *
> + * Initializes the FM module
> + *
> + * @Param[in] p_fm - FM module descriptor
> + *
> + * @Return 0 on success; Error code otherwise.
> + */

I know little about kerneldoc, but this is not kerneldoc, right?

> +/* fm_free
> + * Frees all resources that were assigned to FM module.
> + * Calling this routine invalidates the descriptor.
> + * p_fm - FM module descriptor
> + *Return 0 on success; Error code otherwise.
> + */

Ditto.

> +void fm_event_isr(struct fm_t *p_fm)
> +{
> +#define FM_M_CALL_MAC_ISR(_id) \
> + (p_fm->intr_mng[(enum fm_inter_module_event)(FM_EV_MAC0 + _id)]. \
> + f_isr(p_fm->intr_mng[(enum fm_inter_module_event)(FM_EV_MAC0 + _id)] \
> + .h_src_handle))
> + uint32_t pending;
> + int ret;
> + struct fman_fpm_regs __iomem *fpm_rg;

There must be a nicer way than to put a #define just before the local
variables.

> +int fm_error_isr(struct fm_t *p_fm)
> +{
> +#define FM_M_CALL_MAC_ERR_ISR(_id) \
> + (p_fm->intr_mng[(enum fm_inter_module_event)(FM_EV_ERR_MAC0 + _id)]. \
> + f_isr(p_fm->intr_mng[(enum fm_inter_module_event)\
> + (FM_EV_ERR_MAC0 + _id)].h_src_handle))
> + uint32_t pending;
> + struct fman_fpm_regs __iomem *fpm_rg;
> + int ret;

Ditto.

> --- /dev/null
> +++ b/drivers/net/ethernet/freescale/fman/fm.h

> +/* list_object
> + * Macro to get the struct (object) for this entry.
> + * type - The type of the struct (object) this list
> + * is embedded in.
> + * member - The name of the struct list_head object
> + * within the struct.
> + * Return The structure pointer for this entry.
> + */
> +#define member_offset(type, member) (PTR_TO_UINT(&((type *)0)->member))
> +#define list_object(p_list, type, member) \
> +((type *)((char *)(p_list) - member_offset(type, member)))

Aren't there any global #defines that already do (something like) this?

> +++ b/drivers/net/ethernet/freescale/fman/fm_drv.c

> +static void destroy_fm_dev(struct fm_drv_t *p_fm_drv)
> +{
> + kfree(p_fm_drv);
> +}

Why do you wrap kfree() here?

> +/**
> +*find_fman_microcode - find the Fman microcode
> + *
> +*This function returns a pointer to the QE Firmware blob that holds
> +*the Fman microcode. We use the QE Firmware structure because Fman microcode
> +*is similar to QE microcode, so there's no point in defining a new layout.
> + *
> +*Current versions of U-Boot embed the Fman firmware into the device tree,
> +*so we check for that first. Each Fman node in the device tree contains a
> +*node or a pointer to node that holds the firmware. Technically, we should
> +*be fetching the firmware node for the current Fman, but we don't have that
> +*information any more, so we assume that there is only one firmware node in
> +*the device tree, and that all Fmen use the same firmware.
> + */

/**
*new_style - a new comment style
*
*This is a new style of comment formatting.
*Do people like it?
*/

> +static int /*__devinit*/ fm_probe(struct platform_device *of_dev)

Please remove commented out code before submitting.

> +static const struct of_device_id fm_match[] = {
> + {
> + .compatible = "fsl,fman"},
> + {}
> +};
> +
> +#ifndef MODULE
> +MODULE_DEVICE_TABLE(of, fm_match);
> +#endif /* !MODULE */

include/linux/module.h reads (summarized):
#ifdef MODULE
#define MODULE_DEVICE_TABLE(type, name) \
extern const typeof(name) __mod_##type##__##name##_device_table \
__attribute__ ((unused, alias(__stringify(name))))
#else /* !MODULE */
#define MODULE_DEVICE_TABLE(type, name)
#endif

So please drop the #ifndef wrapper.

> +void *fm_drv_init(void)

static.

> +{
> + memset(&fm_drvs, 0, sizeof(fm_drvs));
> + mutex_init(&fm_drv_mutex);
> +
> + /* Register to the DTB for basic FM API */
> + platform_driver_register(&fm_driver);
> +
> + return &fm_drvs;
> +}
> +
> +int fm_drv_free(void *p_fm_drv)

static.

> +{
> + platform_driver_unregister(&fm_driver);
> + mutex_destroy(&fm_drv_mutex);
> +
> + return 0;
> +}

And p_fm_drv is unused in the function (and see below).

> +static void *p_fm_drv;

> +static int __init __cold fm_load(void)
> +{
> + p_fm_drv = fm_drv_init();
> + if (!p_fm_drv) {
> + pr_err("Failed to init FM wrapper!\n");
> + return -ENODEV;
> + }
> +
> + pr_info("Freescale FM module\n");
> + return 0;
> +}
> +
> +static void __exit __cold fm_unload(void)
> +{
> + if (p_fm_drv)
> + fm_drv_free(p_fm_drv);
> +}

How can p_fm_drv be NULL if fm_load() succeeded? If think that variable
isn't needed at all.

And by the way: p_, because it's a pointer? Don't do that, that's
silly.

> +module_init(fm_load);
> +module_exit(fm_unload);

FSL_FMAN is bool (see 7/12) and fm_drv.o can only be built-in, as far as
I could (quickly) see. But the code is using a few module specific
constructs. Was FSL_FMAN perhaps meant to be tristate?

Thanks,


Paul Bolle



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