Messages in this thread | | | Date | Mon, 29 Sep 2014 22:35:22 -0700 | From | Guenter Roeck <> | Subject | Re: [PATCH v2 4/6] drivers: uio: Add X-Gene QMTM UIO driver |
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On Tue, Sep 30, 2014 at 09:56:07AM +0530, Ankit Jindal wrote: > The Applied Micro X-Gene SOC has on-chip QMTM (Queue manager > and Traffic manager) which is hardware based Queue or Ring > manager. This QMTM device can be used in conjunction with > other devices such as DMA Engine, Ethernet, Security Engine, > etc to assign work based on queues or rings. > > This patch allows user space access to X-Gene QMTM device. > > Signed-off-by: Ankit Jindal <ankit.jindal@linaro.org> > Signed-off-by: Tushar Jagad <tushar.jagad@linaro.org> > --- > drivers/uio/Kconfig | 8 ++ > drivers/uio/Makefile | 1 + > drivers/uio/uio_xgene_qmtm.c | 278 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 287 insertions(+) > create mode 100644 drivers/uio/uio_xgene_qmtm.c > > diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig > index 5a90914..76b1858 100644 > --- a/drivers/uio/Kconfig > +++ b/drivers/uio/Kconfig > @@ -135,4 +135,12 @@ config UIO_MF624 > > If you compile this as a module, it will be called uio_mf624. > > +config UIO_XGENE_QMTM > + tristate "Applied Micro X-Gene QMTM driver" > + depends on OF > + help > + Userspace I/O interface for the X-Gene QMTM. The userspace part of > + this driver will be available for download from the Applied Micro > + web site (http://www.apm.com/). > + > endif > diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile > index d3218bd..633eaa0 100644 > --- a/drivers/uio/Makefile > +++ b/drivers/uio/Makefile > @@ -8,3 +8,4 @@ obj-$(CONFIG_UIO_PCI_GENERIC) += uio_pci_generic.o > obj-$(CONFIG_UIO_NETX) += uio_netx.o > obj-$(CONFIG_UIO_PRUSS) += uio_pruss.o > obj-$(CONFIG_UIO_MF624) += uio_mf624.o > +obj-$(CONFIG_UIO_XGENE_QMTM) += uio_xgene_qmtm.o > diff --git a/drivers/uio/uio_xgene_qmtm.c b/drivers/uio/uio_xgene_qmtm.c > new file mode 100644 > index 0000000..36d9000 > --- /dev/null > +++ b/drivers/uio/uio_xgene_qmtm.c > @@ -0,0 +1,278 @@ > +/* > + * X-Gene Queue Manager Traffic Manager (QMTM) UIO driver (uio_xgene_qmtm) > + * > + * This driver exports QMTM CSRs, Fabric and memory for queues to user-space > + * > + * Copyright (C) 2014 Applied Micro - http://www.apm.com/ > + * Copyright (C) 2014 Linaro Ltd. > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License as > + * published by the Free Software Foundation version 2. > + * > + * This program is distributed "as is" WITHOUT ANY WARRANTY of any > + * kind, whether express or implied; without even the implied warranty > + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/device.h> > +#include <linux/delay.h> > +#include <linux/module.h> > +#include <linux/moduleparam.h> > +#include <linux/platform_device.h> > +#include <linux/uio_driver.h> > +#include <linux/io.h> > +#include <linux/clk.h> > +#include <linux/slab.h> > +#include <linux/of_platform.h> > +#include <linux/of_address.h> > + > +#define DRV_NAME "qmtm_uio" > +#define DRV_VERSION "1.0" > + > +#define QMTM_CFG_MEM_RAM_SHUTDOWN 0x0000d070 > + > +#define QMTM_DEFAULT_QSIZE 65536 > + > +struct uio_qmtm_dev { > + struct uio_info *info; > + struct clk *qmtm_clk; > +}; > + > +/* QMTM CSR read/write routine */ > +static inline void qmtm_csr_write(struct uio_qmtm_dev *qmtm_dev, u32 offset, > + u32 data) > +{ > + void __iomem *addr = qmtm_dev->info->mem[0].internal_addr; > + > + writel(data, addr + offset); > +} > + > +static inline u32 qmtm_csr_read(struct uio_qmtm_dev *qmtm_dev, u32 offset) > +{ > + void __iomem *addr = qmtm_dev->info->mem[0].internal_addr; > + > + return readl(addr + offset); > +} > + > +static int qmtm_reset(struct uio_qmtm_dev *qmtm_dev) > +{ > + u32 val; > + int wait = 1000; > + > + /* reset the internal memory of the device */ > + qmtm_csr_write(qmtm_dev, QMTM_CFG_MEM_RAM_SHUTDOWN, 0); > + > + /* check whether device internal memory is out of reset or not */ > + while (1) {
Seems to me that while (wait--) { ... } return -EBUSY;
would be much easier to understand.
Also, not sure if EBUSY is really appropriate here. ETIMEDOUT, maybe ?
> + val = qmtm_csr_read(qmtm_dev, QMTM_CFG_MEM_RAM_SHUTDOWN); > + > + if (val != 0xffffffff) > + return 0; > + > + if (!wait--) > + return -EBUSY; > + > + udelay(1); > + } > +} > + > +static void qmtm_cleanup(struct platform_device *pdev, > + struct uio_qmtm_dev *qmtm_dev) > +{ > + struct uio_info *info = qmtm_dev->info; > + > + uio_unregister_device(info); > + > + clk_disable_unprepare(qmtm_dev->qmtm_clk); > +} > + > +static int qmtm_probe(struct platform_device *pdev) > +{ > + struct uio_info *info; > + struct uio_qmtm_dev *qmtm_dev; > + struct resource *csr; > + struct resource *fabric; > + struct resource qpool; > + unsigned int num_queues; > + unsigned int devid; > + phandle qpool_phandle; > + struct device_node *qpool_node; > + int ret; > + > + qmtm_dev = devm_kzalloc(&pdev->dev, sizeof(struct uio_qmtm_dev), > + GFP_KERNEL); > + if (!qmtm_dev) > + return -ENOMEM; > + > + qmtm_dev->info = devm_kzalloc(&pdev->dev, sizeof(*info), GFP_KERNEL); > + if (!qmtm_dev->info) > + return -ENOMEM; > + > + /* Power on qmtm in case its not done as part of boot-loader */ > + qmtm_dev->qmtm_clk = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(qmtm_dev->qmtm_clk)) { > + dev_err(&pdev->dev, "Failed to get clock\n"); > + ret = PTR_ERR(qmtm_dev->qmtm_clk); > + return ret; > + } else {
This else is really unnecessary.
> + clk_prepare_enable(qmtm_dev->qmtm_clk);
If you would call this later, just before, say, qmtm_reset, could simplify the code a lot since it could return directly for most of the error cases.
> + } > + > + csr = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + if (!csr) { > + ret = -ENODEV; > + dev_err(&pdev->dev, "No QMTM CSR resource specified\n"); > + goto out_free; > + } > + > + if (!csr->start) { > + ret = -EINVAL; > + dev_err(&pdev->dev, "Invalid CSR resource\n"); > + goto out_free; > + } > + > + fabric = platform_get_resource(pdev, IORESOURCE_MEM, 1); > + if (!fabric) { > + ret = -ENODEV; > + dev_err(&pdev->dev, "No QMTM Fabric resource specified\n"); > + goto out_free; > + } > + > + if (!fabric->start) { > + ret = -EINVAL; > + dev_err(&pdev->dev, "Invalid Fabric resource\n"); > + goto out_free; > + } > + > + ret = of_property_read_u32(pdev->dev.of_node, "qpool", &qpool_phandle); > + Unnecessary empty line before checking results. Doesn't checkpatch complain about that ?
> + if (ret < 0) { > + dev_err(&pdev->dev, "No qpool resource specified\n"); > + goto out_free; > + } > + > + qpool_node = of_find_node_by_phandle(qpool_phandle); > + > + if (IS_ERR_OR_NULL(qpool_node)) { > + ret = PTR_ERR(qpool_node); > + dev_err(&pdev->dev, "Failed to get node by phandle\n"); > + goto out_free; > + } > + > + ret = of_address_to_resource(qpool_node, 0, &qpool); > + > + of_node_put(qpool_node); > + > + if (ret < 0) { > + dev_err(&pdev->dev, "Failed to get qpool resource from node\n"); > + goto out_free; > + } > + > + if (!qpool.start) { > + ret = -EINVAL; > + dev_err(&pdev->dev, "Invalid qpool resource\n"); > + goto out_free; > + } > + > + ret = of_property_read_u32(pdev->dev.of_node, "num-queues", > + &num_queues); > + > + if (ret < 0) { > + dev_err(&pdev->dev, "No num-queues resource specified\n"); > + goto out_free; > + } > + > + /* check whether sufficient memory is provided for the given queues */ > + if (!((num_queues * QMTM_DEFAULT_QSIZE) <= resource_size(&qpool))) {
Some unnecessary ( ), and the negation is a bit odd. Why not just
if (num_queues * QMTM_DEFAULT_QSIZE > resource_size(&qpool)) {
?
> + ret = -ENOSPC; > + dev_err(&pdev->dev, "Insufficient Qpool for the given queues\n"); > + goto out_free; > + } > + > + ret = of_property_read_u32(pdev->dev.of_node, "devid", &devid); > + if (ret < 0) { > + dev_err(&pdev->dev, "No devid resource specified\n"); > + goto out_free; > + } > + > + info = qmtm_dev->info; > + info->mem[0].name = "csr"; > + info->mem[0].addr = csr->start; > + info->mem[0].size = resource_size(csr); > + info->mem[0].memtype = UIO_MEM_PHYS; > + info->mem[0].internal_addr = devm_ioremap_resource(&pdev->dev, csr); > + > + if (IS_ERR(info->mem[0].internal_addr)) { > + ret = PTR_ERR(info->mem[0].internal_addr); > + dev_err(&pdev->dev, "Failed to ioremap CSR region\n"); > + goto out_free; > + } > + > + info->mem[1].name = "fabric"; > + info->mem[1].addr = fabric->start; > + info->mem[1].size = resource_size(fabric); > + info->mem[1].memtype = UIO_MEM_PHYS; > + > + info->mem[2].name = "qpool"; > + info->mem[2].addr = qpool.start; > + info->mem[2].size = resource_size(&qpool); > + info->mem[2].memtype = UIO_MEM_PHYS_CACHE; > + > + info->name = devm_kasprintf(&pdev->dev, GFP_KERNEL, "qmtm%d", devid); > + info->version = DRV_VERSION; > + > + info->priv = qmtm_dev; > + > + /* get the qmtm out of reset */ > + ret = qmtm_reset(qmtm_dev); > + if (ret < 0) { > + dev_err(&pdev->dev, "Failed to reset QMTM\n"); > + goto out_free; > + } > + > + /* register with uio framework */ > + ret = uio_register_device(&pdev->dev, info); > + if (ret < 0) > + goto out_free; > + > + platform_set_drvdata(pdev, qmtm_dev); > + return 0; > + > +out_free:
Kind of misleading. This doesn't really free anything.
> + qmtm_cleanup(pdev, qmtm_dev);
While it is technically ok to call uio_unregister_device if the device wasn't registerd, I don't really think it makes much sense here to call qmtm_cleanup and thus uio_unregister_device (the uio device is never registered).
You might as well name the label out_clk or similar and call clk_disable_unprepare directly.
> + return ret; > +} > + > +static int qmtm_remove(struct platform_device *pdev) > +{ > + struct uio_qmtm_dev *qmtm_dev = platform_get_drvdata(pdev); > + > + qmtm_cleanup(pdev, qmtm_dev);
... and drop this function entirely as it does not really provide any value.
> + return 0; > +} > + > +static struct of_device_id qmtm_match[] = { > + {.compatible = "apm,xgene-qmtm",}, > + {}, > +}; > + > +MODULE_DEVICE_TABLE(of, qmtm_match); > + > +static struct platform_driver qmtm_driver = { > + .driver = { > + .name = DRV_NAME, > + .owner = THIS_MODULE, > + .of_match_table = qmtm_match, > + }, > + .probe = qmtm_probe, > + .remove = qmtm_remove, > +}; > + > +module_platform_driver(qmtm_driver); > + > +MODULE_LICENSE("GPL v2"); > +MODULE_VERSION(DRV_VERSION); > +MODULE_AUTHOR("Ankit Jindal <ankit.jindal@linaro.org>"); > +MODULE_AUTHOR("Tushar Jagad <tushar.jagad@linaro.org>"); > -- > 1.7.9.5 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > >
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