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

Eddie James
2019-07-01T18:39:09Z

On 5/30/19 10:45 PM, Eduardo Valentin wrote:
> 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()?

Yes, will change, and below.

>
>> +
>> + 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/

Doesn't seem to be any way to create attributes per device with that
method. Setting the device->groups in probe() doesn't do it.

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

Patch 4, but yes.

>
>> +
>> 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
>>