Messages in this thread | | | Date | Thu, 19 Sep 2013 12:01:20 +0200 | From | Michal Simek <> | Subject | Re: [RFC PATCH] fpga: Introduce new fpga subsystem |
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Hi Joe,
On 09/18/2013 06:11 PM, Joe Perches wrote: > 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.
This is not a driver just kernel subsystem and real drivers will register itself in this subsystem.
> >> 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. > > []
Fixed.
> >> +/** >> + * 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.
Yeah I know. Will revisit all return codes.
>> +} >> + >> +/** >> + * 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.
yap
> > >> +/** >> + * 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
yap
> >> + 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?
There is another comment to fix this by pointer which is sensible solution too.
Thanks for review, Michal
-- Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91 w: www.monstr.eu p: +42-0-721842854 Maintainer of Linux kernel - Microblaze cpu - http://www.monstr.eu/fdt/ Maintainer of Linux kernel - Xilinx Zynq ARM architecture Microblaze U-BOOT custodian and responsible for u-boot arm zynq platform
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