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SubjectRe: [PATCH 1/2] PRUSS UIO driver support
On Fri, Feb 18, 2011 at 08:35:29PM +0530, Pratheesh Gangadhar wrote:
> Signed-off-by: Pratheesh Gangadhar <pratheesh@ti.com>
>
> This patch implements PRUSS (Programmable Real-time Unit Sub System)
> UIO driver which exports SOC resources associated with PRUSS like
> I/O, memories and IRQs to user space. PRUSS is dual 32-bit RISC
> processors which is efficient in performing embedded tasks that
> require manipulation of packed memory mapped data structures and
> efficient in handling system events that have tight real time
> constraints. This driver is currently supported on Texas Instruments
> DA850, AM18xx and OMAPL1-38 devices.
> For example, PRUSS runs firmware for real-time critical industrial
> communication data link layer and communicates with application stack
> running in user space via shared memory and IRQs.

I see a few issues, comments below.

Thanks,
Hans

> ---
> drivers/uio/Kconfig | 10 ++
> drivers/uio/Makefile | 1 +
> drivers/uio/uio_pruss.c | 250 +++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 261 insertions(+), 0 deletions(-)
> create mode 100644 drivers/uio/uio_pruss.c
>
> diff --git a/drivers/uio/Kconfig b/drivers/uio/Kconfig
> index bb44079..631ffe3 100644
> --- a/drivers/uio/Kconfig
> +++ b/drivers/uio/Kconfig
> @@ -94,4 +94,14 @@ config UIO_NETX
> To compile this driver as a module, choose M here; the module
> will be called uio_netx.
>
> +config UIO_PRUSS
> + tristate "Texas Instruments PRUSS driver"
> + depends on ARCH_DAVINCI_DA850
> + default n

That line is unneccessary, "n" is already the default.

> + help
> + PRUSS driver for OMAPL138/DA850/AM18XX devices
> + PRUSS driver requires user space components
> + To compile this driver as a module, choose M here: the module
> + will be called uio_pruss.
> +
> endif
> diff --git a/drivers/uio/Makefile b/drivers/uio/Makefile
> index 18fd818..d4dd9a5 100644
> --- a/drivers/uio/Makefile
> +++ b/drivers/uio/Makefile
> @@ -6,3 +6,4 @@ obj-$(CONFIG_UIO_AEC) += uio_aec.o
> obj-$(CONFIG_UIO_SERCOS3) += uio_sercos3.o
> obj-$(CONFIG_UIO_PCI_GENERIC) += uio_pci_generic.o
> obj-$(CONFIG_UIO_NETX) += uio_netx.o
> +obj-$(CONFIG_UIO_PRUSS) += uio_pruss.o
> diff --git a/drivers/uio/uio_pruss.c b/drivers/uio/uio_pruss.c
> new file mode 100644
> index 0000000..5ae78a5
> --- /dev/null
> +++ b/drivers/uio/uio_pruss.c
> @@ -0,0 +1,250 @@
> +/*
> + * Programmable Real-Time Unit Sub System (PRUSS) UIO driver (uio_pruss)
> + *
> + * This driver exports PRUSS host event out interrupts and PRUSS, L3 RAM,
> + * and DDR RAM to user space for applications interacting with PRUSS firmware
> + *
> + * Copyright (C) 2010-11 Texas Instruments Incorporated - http://www.ti.com/
> + *
> + * 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/module.h>
> +#include <linux/platform_device.h>
> +#include <linux/uio_driver.h>
> +#include <linux/io.h>
> +#include <linux/clk.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/slab.h>
> +
> +#define DRV_NAME "pruss"
> +#define DRV_VERSION "0.50"
> +
> +/*
> + * Host event IRQ numbers from PRUSS
> + * 3 PRU_EVTOUT0 PRUSS Interrupt
> + * 4 PRU_EVTOUT1 PRUSS Interrupt
> + * 5 PRU_EVTOUT2 PRUSS Interrupt
> + * 6 PRU_EVTOUT3 PRUSS Interrupt
> + * 7 PRU_EVTOUT4 PRUSS Interrupt
> + * 8 PRU_EVTOUT5 PRUSS Interrupt
> + * 9 PRU_EVTOUT6 PRUSS Interrupt
> + * 10 PRU_EVTOUT7 PRUSS Interrupt
> +*/
> +
> +#define MAX_PRUSS_EVTOUT_INSTANCE (8)

The brackets are not needed.

> +
> +static struct clk *pruss_clk;
> +static struct uio_info *info[MAX_PRUSS_EVTOUT_INSTANCE];

is it really neccessary to allocate that statically?

> +static void *ddr_virt_addr;
> +static dma_addr_t ddr_phy_addr;
> +
> +static irqreturn_t pruss_handler(int irq, struct uio_info *dev_info)
> +{
> + return IRQ_HANDLED;
> +}

ROTFL. That reminds me of an old story. The last time I wrote this, and
Greg dared to post it, we received this reply:

http://marc.info/?l=linux-kernel&m=116604101232144&w=2

So, if you really have a _very_ good reason why this _always_ works on
_any_ DA850 board, add a comment that explains why. Otherwise the whole
patch set will be doomed.

> +
> +static int __devinit pruss_probe(struct platform_device *dev)
> +{
> + int ret = -ENODEV;
> + int count = 0;
> + struct resource *regs_pruram, *regs_l3ram, *regs_ddr;
> + char *string;
> +
> + /* Power on PRU in case its not done as part of boot-loader */
> + pruss_clk = clk_get(&dev->dev, "pruss");
> + if (IS_ERR(pruss_clk)) {
> + dev_err(&dev->dev, "Failed to get clock\n");
> + ret = PTR_ERR(pruss_clk);
> + pruss_clk = NULL;
> + return ret;
> + } else {
> + clk_enable(pruss_clk);
> + }
> +
> + for (count = 0; count < MAX_PRUSS_EVTOUT_INSTANCE; count++) {
> + info[count] = kzalloc(sizeof(struct uio_info), GFP_KERNEL);
> + if (!info[count])
> + return -ENOMEM;
> + }
> +
> + regs_pruram = platform_get_resource(dev, IORESOURCE_MEM, 0);
> + if (!regs_pruram) {
> + dev_err(&dev->dev, "No memory resource specified\n");
> + goto out_free;
> + }
> +
> + regs_l3ram = platform_get_resource(dev, IORESOURCE_MEM, 1);
> + if (!regs_l3ram) {
> + dev_err(&dev->dev, "No memory resource specified\n");
> + goto out_free;
> + }
> +
> + regs_ddr = platform_get_resource(dev, IORESOURCE_MEM, 2);
> + if (!regs_ddr) {
> + dev_err(&dev->dev, "No memory resource specified\n");
> + goto out_free;
> + }
> + ddr_virt_addr =
> + dma_alloc_coherent(&dev->dev, regs_ddr->end - regs_ddr->start + 1,
> + &ddr_phy_addr, GFP_KERNEL | GFP_DMA);
> + if (!ddr_virt_addr) {
> + dev_err(&dev->dev, "Could not allocate external memory\n");
> + goto out_free;
> + }
> +
> + for (count = 0; count < MAX_PRUSS_EVTOUT_INSTANCE; count++) {
> + info[count]->mem[0].addr = regs_pruram->start;
> + info[count]->mem[0].size =
> + regs_pruram->end - regs_pruram->start + 1;
> + if (!info[count]->mem[0].addr
> + || !(info[count]->mem[0].size - 1)) {

That size check looks fishy. If somebody forgot to set the size it's OK ?

> + dev_err(&dev->dev, "Invalid memory resource\n");
> + break;
> + }
> + info[count]->mem[0].internal_addr =
> + ioremap(regs_pruram->start, info[count]->mem[0].size);
> + if (!info[count]->mem[0].internal_addr) {
> + dev_err(&dev->dev,
> + "Can't remap memory address range\n");
> + break;
> + }
> + info[count]->mem[0].memtype = UIO_MEM_PHYS;
> +
> + info[count]->mem[1].addr = regs_l3ram->start;
> + info[count]->mem[1].size =
> + regs_l3ram->end - regs_l3ram->start + 1;
> + if (!info[count]->mem[1].addr
> + || !(info[count]->mem[1].size - 1)) {
> + dev_err(&dev->dev, "Invalid memory resource\n");
> + break;
> + }
> + info[count]->mem[1].internal_addr =
> + ioremap(regs_l3ram->start, info[count]->mem[1].size);
> + if (!info[count]->mem[1].internal_addr) {
> + dev_err(&dev->dev,
> + "Can't remap memory address range\n");
> + break;
> + }
> + info[count]->mem[1].memtype = UIO_MEM_PHYS;
> +
> + info[count]->mem[2].addr = ddr_phy_addr;
> + info[count]->mem[2].size = regs_ddr->end - regs_ddr->start + 1;
> + if (!info[count]->mem[2].addr
> + || !(info[count]->mem[2].size - 1)) {
> + dev_err(&dev->dev, "Invalid memory resource\n");
> + break;
> + }
> + info[count]->mem[2].internal_addr = ddr_virt_addr;
> + if (!info[count]->mem[2].internal_addr) {
> + dev_err(&dev->dev,
> + "Can't remap memory address range\n");
> + break;
> + }
> + info[count]->mem[2].memtype = UIO_MEM_PHYS;
> +
> + string = kzalloc(20, GFP_KERNEL);
> + sprintf(string, "pruss_evt%d", count);
> + info[count]->name = string;
> + info[count]->version = "0.50";
> +
> + /* Register PRUSS IRQ lines */
> + info[count]->irq = IRQ_DA8XX_EVTOUT0 + count;
> +
> + info[count]->irq_flags = IRQF_SHARED;

How do you handle shared interrupts with the handler above?

> + info[count]->handler = pruss_handler;

And how do you make sure your interrupts are not level triggered? The
handler above will hang for level triggered interrupts.

> +
> + ret = uio_register_device(&dev->dev, info[count]);
> +
> + if (ret < 0)
> + break;
> + }
> +
> + if (ret < 0) {
> + if (ddr_virt_addr)
> + dma_free_coherent(&dev->dev,
> + regs_ddr->end - regs_ddr->start + 1,
> + ddr_virt_addr, ddr_phy_addr);
> + while (count--) {
> + uio_unregister_device(info[count]);
> + kfree(info[count]->name);
> + iounmap(info[count]->mem[0].internal_addr);
> + }
> + } else {
> + platform_set_drvdata(dev, info);
> + return 0;
> + }
> +
> +out_free:
> + for (count = 0; count < MAX_PRUSS_EVTOUT_INSTANCE; count++)
> + kfree(info[count]);
> +
> + if (pruss_clk != NULL)
> + clk_put(pruss_clk);
> +
> + return ret;
> +}
> +
> +static int __devexit pruss_remove(struct platform_device *dev)
> +{
> + int count = 0;
> + struct uio_info **info;
> +
> + info = (struct uio_info **)platform_get_drvdata(dev);
> +
> + for (count = 0; count < MAX_PRUSS_EVTOUT_INSTANCE; count++) {
> + uio_unregister_device(info[count]);
> + kfree(info[count]->name);
> +
> + }
> + iounmap(info[0]->mem[0].internal_addr);
> + iounmap(info[0]->mem[1].internal_addr);
> + if (ddr_virt_addr)
> + dma_free_coherent(&dev->dev, info[0]->mem[2].size,
> + info[0]->mem[2].internal_addr,
> + info[0]->mem[2].addr);
> +
> + for (count = 0; count < MAX_PRUSS_EVTOUT_INSTANCE; count++)
> + kfree(info[count]);
> +
> + platform_set_drvdata(dev, NULL);
> +
> + if (pruss_clk != NULL)
> + clk_put(pruss_clk);
> + return 0;
> +}
> +
> +static struct platform_driver pruss_driver = {
> + .probe = pruss_probe,
> + .remove = __devexit_p(pruss_remove),
> + .driver = {
> + .name = DRV_NAME,
> + .owner = THIS_MODULE,
> + },
> +};
> +
> +static int __init pruss_init_module(void)
> +{
> + return platform_driver_register(&pruss_driver);
> +}
> +
> +module_init(pruss_init_module);
> +
> +static void __exit pruss_exit_module(void)
> +{
> + platform_driver_unregister(&pruss_driver);
> +}
> +
> +module_exit(pruss_exit_module);
> +
> +MODULE_LICENSE("GPL v2");
> +MODULE_VERSION(DRV_VERSION);
> +MODULE_AUTHOR("Amit Chatterjee <amit.chatterjee@ti.com>");
> +MODULE_AUTHOR("Pratheesh Gangadhar <pratheesh@ti.com>");
> --
> 1.6.0.6
>
> --
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