Re: [PATCH v3 5/8] drivers/soc: xdma: Add PCI device configuration sysfs

Eduardo Valentin
2019-05-31T03:45:09Z

On Wed, May 29, 2019 at 01:10:05PM -0500, Eddie James wrote:
> The AST2500 has two PCI devices embedded. The XDMA engine can use either
> device to perform DMA transfers. Users need the capability to choose
> which device to use. This commit therefore adds two sysfs files that
> toggle the AST2500 and XDMA engine between the two PCI devices.
>
> Signed-off-by: Eddie James <eajames@linux.ibm.com>
> ---
> drivers/soc/aspeed/aspeed-xdma.c | 103 +++++++++++++++++++++++++++++++++++++--
> 1 file changed, 100 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/soc/aspeed/aspeed-xdma.c b/drivers/soc/aspeed/aspeed-xdma.c
> index 39f6545..ddd5e1e 100644
> --- a/drivers/soc/aspeed/aspeed-xdma.c
> +++ b/drivers/soc/aspeed/aspeed-xdma.c
> @@ -143,6 +143,7 @@ struct aspeed_xdma {
> void *cmdq_vga_virt;
> struct gen_pool *vga_pool;
>
> + char pcidev[4];
> struct miscdevice misc;
> };
>
> @@ -165,6 +166,10 @@ struct aspeed_xdma_client {
> SCU_PCIE_CONF_VGA_EN_IRQ | SCU_PCIE_CONF_VGA_EN_DMA |
> SCU_PCIE_CONF_RSVD;
>
> +static char *_pcidev = "vga";
> +module_param_named(pcidev, _pcidev, charp, 0600);
> +MODULE_PARM_DESC(pcidev, "Default PCI device used by XDMA engine for DMA ops");
> +
> static void aspeed_scu_pcie_write(struct aspeed_xdma *ctx, u32 conf)
> {
> u32 v = 0;
> @@ -512,7 +517,7 @@ static int aspeed_xdma_release(struct inode *inode, struct file *file)
> .release = aspeed_xdma_release,
> };
>
> -static int aspeed_xdma_init_mem(struct aspeed_xdma *ctx)
> +static int aspeed_xdma_init_mem(struct aspeed_xdma *ctx, u32 conf)
> {
> int rc;
> u32 scu_conf = 0;
> @@ -522,7 +527,7 @@ static int aspeed_xdma_init_mem(struct aspeed_xdma *ctx)
> const u32 vga_sizes[4] = { 0x800000, 0x1000000, 0x2000000, 0x4000000 };
> void __iomem *sdmc_base = ioremap(0x1e6e0000, 0x100);
>
> - aspeed_scu_pcie_write(ctx, aspeed_xdma_vga_pcie_conf);
> + aspeed_scu_pcie_write(ctx, conf);
>
> regmap_read(ctx->scu, SCU_STRAP, &scu_conf);
> ctx->vga_size = vga_sizes[FIELD_GET(SCU_STRAP_VGA_MEM, scu_conf)];
> @@ -598,10 +603,91 @@ static int aspeed_xdma_init_mem(struct aspeed_xdma *ctx)
> return rc;
> }
>
> +static int aspeed_xdma_change_pcie_conf(struct aspeed_xdma *ctx, u32 conf)
> +{
> + int rc;
> +
> + mutex_lock(&ctx->start_lock);
> + rc = wait_event_interruptible_timeout(ctx->wait,
> + !test_bit(XDMA_IN_PRG,
> + &ctx->flags),
> + msecs_to_jiffies(1000));
> + if (rc < 0) {
> + mutex_unlock(&ctx->start_lock);
> + return -EINTR;
> + }
> +
> + /* previous op didn't complete, wake up waiters anyway */
> + if (!rc)
> + wake_up_interruptible_all(&ctx->wait);
> +
> + reset_control_assert(ctx->reset);
> + msleep(10);
> +
> + aspeed_scu_pcie_write(ctx, conf);
> + msleep(10);
> +
> + reset_control_deassert(ctx->reset);
> + msleep(10);
> +
> + aspeed_xdma_init_eng(ctx);
> +
> + mutex_unlock(&ctx->start_lock);
> +
> + return 0;
> +}
> +
> +static int aspeed_xdma_pcidev_to_conf(struct aspeed_xdma *ctx,
> + const char *pcidev, u32 *conf)
> +{
> + if (!strcasecmp(pcidev, "vga")) {
> + *conf = aspeed_xdma_vga_pcie_conf;
> + return 0;
> + }
> +
> + if (!strcasecmp(pcidev, "bmc")) {
> + *conf = aspeed_xdma_bmc_pcie_conf;
> + return 0;
> + }

strncasecmp()?

> +
> + return -EINVAL;
> +}
> +
> +static ssize_t aspeed_xdma_show_pcidev(struct device *dev,
> + struct device_attribute *attr,
> + char *buf)
> +{
> + struct aspeed_xdma *ctx = dev_get_drvdata(dev);
> +
> + return snprintf(buf, PAGE_SIZE - 1, "%s", ctx->pcidev);
> +}
> +
> +static ssize_t aspeed_xdma_store_pcidev(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + u32 conf;
> + struct aspeed_xdma *ctx = dev_get_drvdata(dev);
> + int rc = aspeed_xdma_pcidev_to_conf(ctx, buf, &conf);
> +
> + if (rc)
> + return rc;
> +
> + rc = aspeed_xdma_change_pcie_conf(ctx, conf);
> + if (rc)
> + return rc;
> +
> + strcpy(ctx->pcidev, buf);

should we use strncpy() instead?

> + return count;
> +}
> +static DEVICE_ATTR(pcidev, 0644, aspeed_xdma_show_pcidev,
> + aspeed_xdma_store_pcidev);
> +
> static int aspeed_xdma_probe(struct platform_device *pdev)
> {
> int irq;
> int rc;
> + u32 conf;
> struct resource *res;
> struct device *dev = &pdev->dev;
> struct aspeed_xdma *ctx = devm_kzalloc(dev, sizeof(*ctx), GFP_KERNEL);
> @@ -657,7 +743,14 @@ static int aspeed_xdma_probe(struct platform_device *pdev)
>
> msleep(10);
>
> - rc = aspeed_xdma_init_mem(ctx);
> + if (aspeed_xdma_pcidev_to_conf(ctx, _pcidev, &conf)) {
> + conf = aspeed_xdma_vga_pcie_conf;
> + strcpy(ctx->pcidev, "vga");
> + } else {
> + strcpy(ctx->pcidev, _pcidev);
> + }

same...

> +
> + rc = aspeed_xdma_init_mem(ctx, conf);
> if (rc) {
> reset_control_assert(ctx->reset);
> return rc;
> @@ -682,6 +775,8 @@ static int aspeed_xdma_probe(struct platform_device *pdev)
> return rc;
> }
>
> + device_create_file(dev, &dev_attr_pcidev);

Should we consider using one of the default attributes here instead of device_create_file()?
http://kroah.com/log/blog/2013/06/26/how-to-create-a-sysfs-file-correctly/

BTW, was this ABI documented? Is this the same file documented in patch 2?

> +
> return 0;
> }
>
> @@ -689,6 +784,8 @@ static int aspeed_xdma_remove(struct platform_device *pdev)
> {
> struct aspeed_xdma *ctx = platform_get_drvdata(pdev);
>
> + device_remove_file(ctx->dev, &dev_attr_pcidev);
> +
> misc_deregister(&ctx->misc);
> gen_pool_free(ctx->vga_pool, (unsigned long)ctx->cmdq_vga_virt,
> XDMA_CMDQ_SIZE);
> --
> 1.8.3.1
>

--
All the best,
Eduardo Valentin