Skip to content

Commit

Permalink
software/kernel/main: Add a few comments.
Browse files Browse the repository at this point in the history
  • Loading branch information
@enjoy-digital
enjoy-digital committed Oct 2, 2024
1 parent aa67c65 commit 9255e10
Showing 1 changed file with 41 additions and 18 deletions.
59 changes: 41 additions & 18 deletions litepcie/software/kernel/main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -90,17 +90,18 @@ struct litepcie_chan {
int minor;
};

/* Structure to hold the LitePCIe device information */
struct litepcie_device {
struct pci_dev *dev;
struct platform_device *uart;
resource_size_t bar0_size;
phys_addr_t bar0_phys_addr;
uint8_t *bar0_addr; /* virtual address of BAR0 */
struct litepcie_chan chan[DMA_CHANNEL_COUNT];
spinlock_t lock;
int minor_base;
int irqs;
int channels;
struct pci_dev *dev; /* PCI device */
struct platform_device *uart; /* UART platform device */
resource_size_t bar0_size; /* Size of BAR0 */
phys_addr_t bar0_phys_addr; /* Physical address of BAR0 */
uint8_t *bar0_addr; /* Virtual address of BAR0 */
struct litepcie_chan chan[DMA_CHANNEL_COUNT]; /* DMA channel information */
spinlock_t lock; /* Spinlock for synchronization */
int minor_base; /* Base minor number for the device */
int irqs; /* Number of IRQs */
int channels; /* Number of DMA channels */
};

struct litepcie_chan_priv {
Expand All @@ -114,6 +115,7 @@ static int litepcie_minor_idx;
static struct class *litepcie_class;
static dev_t litepcie_dev_t;

/* Function to read a 32-bit value from a LitePCIe device register */
static inline uint32_t litepcie_readl(struct litepcie_device *s, uint32_t addr)
{
uint32_t val;
Expand All @@ -125,6 +127,7 @@ static inline uint32_t litepcie_readl(struct litepcie_device *s, uint32_t addr)
return val;
}

/* Function to write a 32-bit value to a LitePCIe device register */
static inline void litepcie_writel(struct litepcie_device *s, uint32_t addr, uint32_t val)
{
#ifdef DEBUG_CSR
Expand All @@ -133,21 +136,33 @@ static inline void litepcie_writel(struct litepcie_device *s, uint32_t addr, uin
return writel(val, s->bar0_addr + addr - CSR_BASE);
}

/* Function to enable a specific interrupt on a LitePCIe device */
static void litepcie_enable_interrupt(struct litepcie_device *s, int irq_num)
{
uint32_t v;

/* Read the current interrupt enable register value */
v = litepcie_readl(s, CSR_PCIE_MSI_ENABLE_ADDR);

/* Set the bit corresponding to the given interrupt number */
v |= (1 << irq_num);

/* Write the updated value back to the register */
litepcie_writel(s, CSR_PCIE_MSI_ENABLE_ADDR, v);
}

/* Function to disable a specific interrupt on a LitePCIe device */
static void litepcie_disable_interrupt(struct litepcie_device *s, int irq_num)
{
uint32_t v;

/* Read the current interrupt enable register value */
v = litepcie_readl(s, CSR_PCIE_MSI_ENABLE_ADDR);

/* Clear the bit corresponding to the given interrupt number */
v &= ~(1 << irq_num);

/* Write the updated value back to the register */
litepcie_writel(s, CSR_PCIE_MSI_ENABLE_ADDR, v);
}

Expand Down Expand Up @@ -986,6 +1001,7 @@ int compare_revisions(struct revision d1, struct revision d2)
}
/* from stackoverflow */

/* Function to probe the LitePCIe PCI device */
static int litepcie_pci_probe(struct pci_dev *dev, const struct pci_device_id *id)
{
int ret = 0;
Expand All @@ -1000,6 +1016,7 @@ static int litepcie_pci_probe(struct pci_dev *dev, const struct pci_device_id *i

dev_info(&dev->dev, "\e[1m[Probing device]\e[0m\n");

/* Allocate memory for the LitePCIe device structure */
litepcie_dev = devm_kzalloc(&dev->dev, sizeof(struct litepcie_device), GFP_KERNEL);
if (!litepcie_dev) {
ret = -ENOMEM;
Expand All @@ -1010,6 +1027,7 @@ static int litepcie_pci_probe(struct pci_dev *dev, const struct pci_device_id *i
litepcie_dev->dev = dev;
spin_lock_init(&litepcie_dev->lock);

/* Enable the PCI device */
ret = pcim_enable_device(dev);
if (ret != 0) {
dev_err(&dev->dev, "Cannot enable device\n");
Expand All @@ -1018,19 +1036,20 @@ static int litepcie_pci_probe(struct pci_dev *dev, const struct pci_device_id *i

ret = -EIO;

/* Check device version */
/* Check the device version */
pci_read_config_byte(dev, PCI_REVISION_ID, &rev_id);
if (rev_id != 0) {
dev_err(&dev->dev, "Unsupported device version %d\n", rev_id);
goto fail1;
}

/* Check bar0 config */
/* Check the BAR0 configuration */
if (!(pci_resource_flags(dev, 0) & IORESOURCE_MEM)) {
dev_err(&dev->dev, "Invalid BAR0 configuration\n");
goto fail1;
}

/* Request and map BAR0 */
if (pcim_iomap_regions(dev, BIT(0), LITEPCIE_NAME) < 0) {
dev_err(&dev->dev, "Could not request regions\n");
goto fail1;
Expand All @@ -1048,9 +1067,9 @@ static int litepcie_pci_probe(struct pci_dev *dev, const struct pci_device_id *i
msleep(10);
#endif

/* Show identifier */
/* Read and display the FPGA identifier */
for (i = 0; i < 256; i++)
fpga_identifier[i] = litepcie_readl(litepcie_dev, CSR_IDENTIFIER_MEM_BASE + i*4);
fpga_identifier[i] = litepcie_readl(litepcie_dev, CSR_IDENTIFIER_MEM_BASE + i * 4);
dev_info(&dev->dev, "Version %s\n", fpga_identifier);

pci_set_master(dev);
Expand All @@ -1062,7 +1081,7 @@ static int litepcie_pci_probe(struct pci_dev *dev, const struct pci_device_id *i
if (ret) {
dev_err(&dev->dev, "Failed to set DMA mask\n");
goto fail1;
};
}


/* MSI-X */
Expand All @@ -1089,6 +1108,7 @@ static int litepcie_pci_probe(struct pci_dev *dev, const struct pci_device_id *i
for (i = 0; i < irqs; i++) {
int irq = pci_irq_vector(dev, i);

/* Request IRQ */
ret = request_irq(irq, litepcie_interrupt, 0, LITEPCIE_NAME, litepcie_dev);
if (ret < 0) {
dev_err(&dev->dev, " Failed to allocate IRQ %d\n", dev->irq);
Expand Down Expand Up @@ -1218,6 +1238,7 @@ static int litepcie_pci_probe(struct pci_dev *dev, const struct pci_device_id *i
return ret;
}

/* Function to remove the LitePCIe PCI device */
static void litepcie_pci_remove(struct pci_dev *dev)
{
int i, irq;
Expand All @@ -1233,7 +1254,7 @@ static void litepcie_pci_remove(struct pci_dev *dev)
/* Disable all interrupts */
litepcie_writel(litepcie_dev, CSR_PCIE_MSI_ENABLE_ADDR, 0);

/* Free all interrupts */
/* Free all IRQs */
for (i = 0; i < litepcie_dev->irqs; i++) {
irq = pci_irq_vector(dev, i);
free_irq(irq, litepcie_dev);
Expand All @@ -1246,6 +1267,7 @@ static void litepcie_pci_remove(struct pci_dev *dev)
pci_free_irq_vectors(dev);
}

/* PCI device ID table */
static const struct pci_device_id litepcie_pci_ids[] = {
/* Xilinx */
{ PCI_DEVICE(PCIE_XILINX_VENDOR_ID, PCIE_XILINX_DEVICE_ID_S7_GEN2_X1), },
Expand Down Expand Up @@ -1290,14 +1312,15 @@ static const struct pci_device_id litepcie_pci_ids[] = {
};
MODULE_DEVICE_TABLE(pci, litepcie_pci_ids);

/* PCI driver structure */
static struct pci_driver litepcie_pci_driver = {
.name = LITEPCIE_NAME,
.id_table = litepcie_pci_ids,
.probe = litepcie_pci_probe,
.remove = litepcie_pci_remove,
};


/* Module initialization function */
static int __init litepcie_module_init(void)
{
int ret;
Expand Down Expand Up @@ -1337,14 +1360,14 @@ static int __init litepcie_module_init(void)
return ret;
}

/* Module exit function */
static void __exit litepcie_module_exit(void)
{
pci_unregister_driver(&litepcie_pci_driver);
unregister_chrdev_region(litepcie_dev_t, LITEPCIE_MINOR_COUNT);
class_destroy(litepcie_class);
}


module_init(litepcie_module_init);
module_exit(litepcie_module_exit);

Expand Down

0 comments on commit 9255e10

Please sign in to comment.