Messages in this thread | | | Subject | Re: [RFC PATCH] fpga: Introduce new fpga subsystem | From | Joe Perches <> | Date | Wed, 18 Sep 2013 09:11:05 -0700 |
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On Wed, 2013-09-18 at 17:56 +0200, Michal Simek wrote: > This new subsystem should unify all fpga drivers which > do the same things. Load configuration data to fpga > or another programmable logic through common interface. > It doesn't matter if it is MMIO device, gpio bitbanging, > etc. connection. The point is to have the same > inteface for these drivers.
Is this really a "driver". Perhaps it's more of a core kernel function and belongs in kernel.
> diff --git a/drivers/fpga/fpga-mgr.c b/drivers/fpga/fpga-mgr.c
The error messages are a little shouty with all the unnecessary "!" uses.
[]
> +/** > + * fpga_mgr_read - Read data from fpga > + * @mgr: Pointer to the fpga manager structure > + * @buf: Pointer to the buffer location > + * @count: Pointer to the number of copied bytes > + * > + * Function reads fpga bitstream and copy them to output buffer. > + * > + * Returns the number of bytes copied to @buf, a negative error number otherwise > + */ > +static int fpga_mgr_read(struct fpga_manager *mgr, char *buf, ssize_t *count) > +{ > + int ret; > + > + if (test_and_set_bit_lock(FPGA_MGR_DEV_BUSY, &mgr->flags)) > + return -EBUSY; > + > + if (!mgr->mops || !mgr->mops->read) { > + dev_err(mgr->dev, > + "Controller doesn't support read operations!\n"); > + return -EPERM; > + } > + > + if (mgr->mops->read_init) { > + ret = mgr->mops->read_init(mgr); > + if (ret) { > + dev_err(mgr->dev, "Failed in read-init!\n"); > + return ret; > + } > + } > + > + if (mgr->mops->read) { > + ret = mgr->mops->read(mgr, buf, count); > + if (ret) { > + dev_err(mgr->dev, "Failed to read firmware!\n"); > + return ret; > + } > + } > + > + if (mgr->mops->read_complete) { > + ret = mgr->mops->read_complete(mgr); > + if (ret) { > + dev_err(mgr->dev, "Failed in read-complete!\n"); > + return ret; > + } > + } > + > + clear_bit_unlock(FPGA_MGR_DEV_BUSY, &mgr->flags); > + > + return 0; > +} > + > +/** > + * fpga_mgr_attr_read - Read data from fpga > + * @dev: Pointer to the device structure > + * @attr: Pointer to the device attribute structure > + * @buf: Pointer to the buffer location > + * > + * Function reads fpga bitstream and copy them to output buffer > + * > + * Returns the number of bytes copied to @buf, a negative error number otherwise > + */ > +static ssize_t fpga_mgr_attr_read(struct device *dev, > + struct device_attribute *attr, char *buf) > +{ > + struct fpga_manager *mgr = dev_get_drvdata(dev); > + ssize_t count; > + int ret; > + > + if (mgr && mgr->fpga_read) > + ret = mgr->fpga_read(mgr, buf, &count); > + > + return ret == 0 ? count : -EPERM;
EPERM isn't the only error return from fpga_read.
> +} > + > +/** > + * fpga_mgr_write - Write data to fpga > + * @mgr: Pointer to the fpga manager structure > + * @fw_name: Pointer to the buffer location with bistream firmware filename > + * > + * @buf contains firmware filename which is loading through firmware > + * interface and passed to the fpga driver. > + * > + * Returns string lenght added to @fw_name, a negative error number otherwise > + */ > +static int fpga_mgr_write(struct fpga_manager *mgr, const char *fw_name) > +{ > + int ret = 0; > + const struct firmware *fw; > + > + if (!fw_name || !strlen(fw_name)) { > + dev_err(mgr->dev, "Firmware name is not specified!\n"); > + return -EINVAL; > + } > + > + if (!mgr->mops || !mgr->mops->write) { > + dev_err(mgr->dev, > + "Controller doesn't support write operations!\n"); > + return -EPERM;
I think you should revisit the return codes.
> +/** > + * fpga_mgr_attr_write - Write data to fpga > + * @dev: Pointer to the device structure > + * @attr: Pointer to the device attribute structure > + * @buf: Pointer to the buffer location with bistream firmware filename > + * @count: Number of characters in @buf > + * > + * @buf contains firmware filename which is loading through firmware > + * interface and passed to the fpga driver. > + * > + * Returns string lenght added to @buf, a negative error number otherwise > + */ > +static ssize_t fpga_mgr_attr_write(struct device *dev, > + struct device_attribute *attr, > + const char *buf, size_t count) > +{ > + struct fpga_manager *mgr = dev_get_drvdata(dev); > + int ret; > + > + if (mgr && mgr->fpga_write) > + ret = mgr->fpga_write(mgr, buf); > + > + return ret == 0 ? strlen(buf) : -EPERM; > +}
Same -EPERM issue as read
> + mgr = devm_kzalloc(&pdev->dev, sizeof(*mgr), GFP_KERNEL); > + if (!mgr) { > + dev_err(&pdev->dev, "Failed to alloc mgr struct!\n");
Unnecessary OOM message as there's a general dump_stack() already done on any OOM without GFP_NOWARN
> diff --git a/include/linux/fpga.h b/include/linux/fpga.h [] > +struct fpga_manager { > + char name[48];
Maybe a #define instead of 48?
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