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SubjectRe: [PATCH v10 1/3] dmaengine: ptdma: Initial driver for the AMD PTDMA
On 20-06-21, 11:41, Sanjay R Mehta wrote:

> +static irqreturn_t pt_core_irq_handler(int irq, void *data)
> +{
> + struct pt_device *pt = data;
> + struct pt_cmd_queue *cmd_q = &pt->cmd_q;
> + u32 status;
> + bool err = true;
> +
> + pt_core_disable_queue_interrupts(pt);
> +
> + status = ioread32(cmd_q->reg_interrupt_status);
> + if (status) {
> + cmd_q->int_status = status;
> + cmd_q->q_status = ioread32(cmd_q->reg_status);
> + cmd_q->q_int_status = ioread32(cmd_q->reg_int_status);
> +
> + /* On error, only save the first error value */
> + if ((status & INT_ERROR) && !cmd_q->cmd_error) {
> + cmd_q->cmd_error = CMD_Q_ERROR(cmd_q->q_status);
> + err = false;
> + }
> +
> + /* Acknowledge the interrupt */
> + iowrite32(status, cmd_q->reg_interrupt_status);
> + }
> +
> + pt_core_enable_queue_interrupts(pt);
> +
> + return err ? IRQ_HANDLED : IRQ_NONE;

On err you should not return IRQ_NONE. IRQ_NONE means "interrupt was not
from this device or was not handled"

Error is handled here!

> +static struct pt_device *pt_alloc_struct(struct device *dev)
> +{
> + struct pt_device *pt;
> +
> + pt = devm_kzalloc(dev, sizeof(*pt), GFP_KERNEL);
> +
> + if (!pt)
> + return NULL;
> + pt->dev = dev;
> +
> + INIT_LIST_HEAD(&pt->cmd);
> +
> + snprintf(pt->name, MAX_PT_NAME_LEN, "pt-%s", dev_name(dev));

what is this name used for? Why not use dev_name everywhere?

> +static int pt_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> +{
> + struct pt_device *pt;
> + struct pt_msix *pt_msix;
> + struct device *dev = &pdev->dev;
> + void __iomem * const *iomap_table;
> + int bar_mask;
> + int ret = -ENOMEM;
> +
> + pt = pt_alloc_struct(dev);
> + if (!pt)
> + goto e_err;
> +
> + pt_msix = devm_kzalloc(dev, sizeof(*pt_msix), GFP_KERNEL);
> + if (!pt_msix)
> + goto e_err;
> +
> + pt->pt_msix = pt_msix;
> + pt->dev_vdata = (struct pt_dev_vdata *)id->driver_data;
> + if (!pt->dev_vdata) {
> + ret = -ENODEV;
> + dev_err(dev, "missing driver data\n");
> + goto e_err;
> + }
> +
> + ret = pcim_enable_device(pdev);
> + if (ret) {
> + dev_err(dev, "pcim_enable_device failed (%d)\n", ret);
> + goto e_err;
> + }
> +
> + bar_mask = pci_select_bars(pdev, IORESOURCE_MEM);
> + ret = pcim_iomap_regions(pdev, bar_mask, "ptdma");
> + if (ret) {
> + dev_err(dev, "pcim_iomap_regions failed (%d)\n", ret);
> + goto e_err;
> + }
> +
> + iomap_table = pcim_iomap_table(pdev);
> + if (!iomap_table) {
> + dev_err(dev, "pcim_iomap_table failed\n");
> + ret = -ENOMEM;
> + goto e_err;
> + }
> +
> + pt->io_regs = iomap_table[pt->dev_vdata->bar];
> + if (!pt->io_regs) {
> + dev_err(dev, "ioremap failed\n");
> + ret = -ENOMEM;
> + goto e_err;
> + }
> +
> + ret = pt_get_irqs(pt);
> + if (ret)
> + goto e_err;
> +
> + pci_set_master(pdev);
> +
> + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(48));
> + if (ret) {
> + ret = dma_set_mask_and_coherent(dev, DMA_BIT_MASK(32));
> + if (ret) {
> + dev_err(dev, "dma_set_mask_and_coherent failed (%d)\n",
> + ret);
> + goto e_err;
> + }
> + }
> +
> + dev_set_drvdata(dev, pt);
> +
> + if (pt->dev_vdata)
> + ret = pt_core_init(pt);
> +
> + if (ret)
> + goto e_err;
> +
> + return 0;
> +
> +e_err:
> + dev_err(dev, "initialization failed\n");

log the err code, that is very useful!

> + /* Register addresses for queue */
> + void __iomem *reg_control;
> + void __iomem *reg_tail_lo;
> + void __iomem *reg_head_lo;
> + void __iomem *reg_int_enable;
> + void __iomem *reg_interrupt_status;
> + void __iomem *reg_status;
> + void __iomem *reg_int_status;
> + void __iomem *reg_dma_status;
> + void __iomem *reg_dma_read_status;
> + void __iomem *reg_dma_write_status;

this looks like pointer to registers, wont it make sense to keep base
ptr and use offset to read..?

Looking at pt_init_cmdq_regs(), i think that seems to be the case. Why
waste so much memory by having so many pointers?


> + u32 qcontrol; /* Cached control register */
> +
> + /* Status values from job */
> + u32 int_status;
> + u32 q_status;
> + u32 q_int_status;
> + u32 cmd_error;
> +} ____cacheline_aligned;
> +
> +struct pt_device {
> + struct list_head entry;
> +
> + unsigned int ord;

Unused?

--
~Vinod

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