pm8001_pci_probe函数分析之pm8001_pci_alloc

最新推荐文章于 2024-03-05 16:54:49 发布

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最新推荐文章于 2024-03-05 16:54:49 发布 · 997 阅读

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#linux kernel

本文详细剖析了Linux内核中pm8001_pci_probe函数的实现，重点集中在pm8001_pci_alloc部分。通过对代码的逐行解读，揭示了该函数在设备初始化过程中的关键步骤和作用，为理解PCI设备驱动的交互提供了深入洞察。

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接着分析pm8001_pci_probe中调用的pm8001_pci_alloc和scsi_scan_host。先分析pm8001_pci_alloc，在下一篇文章中分析scsi_scan_host

先把pm8001_pci_alloc的代码贴在下面：

/**
 * pm8001_pci_alloc - initialize our ha card structure
 * @pdev: pci device.
 * @ent: ent
 * @shost: scsi host struct which has been initialized before.
 */
static struct pm8001_hba_info *__devinit
pm8001_pci_alloc(struct pci_dev *pdev, u32 chip_id, struct Scsi_Host *shost)
{
	struct pm8001_hba_info *pm8001_ha;//struct pm8001_hba_info represent HBA in lldd layer
	struct sas_ha_struct *sha = SHOST_TO_SAS_HA(shost);//struct sas_ha_struct represent HBA in libsas layer


	pm8001_ha = sha->lldd_ha;//mem alloced in pm8001_prep_sas_ha_init with kzalloc
	if (!pm8001_ha)
		return NULL;
        
        //init part of struct pm8001_hba_info 
	pm8001_ha->pdev = pdev;
	pm8001_ha->dev = &pdev->dev;
	pm8001_ha->chip_id = chip_id;
	pm8001_ha->chip = &pm8001_chips[pm8001_ha->chip_id];
	pm8001_ha->irq = pdev->irq;
	pm8001_ha->sas = sha;
	pm8001_ha->shost = shost;
	pm8001_ha->id = pm8001_id++;
	pm8001_ha->logging_level = logging_level;
	pm8001_ha->ses = 0x0;

	sprintf(pm8001_ha->name, "%s%d", DRV_NAME, pm8001_ha->id);
        

        //remap the pci high physical address to kernel virtual

  pm8001_ioremap(pm8001_ha);//注意1
if (!pm8001_alloc(pm8001_ha))//注意2
return pm8001_ha;
pm8001_free(pm8001_ha);
return NULL;
}

注意1：pm8001_ioremap - remap the pci high physical address to kernal virtual address so that we can access them.

pm8001_ioremap的代码如下：

/**
 * pm8001_ioremap - remap the pci high physical address to kernal virtual
 * address so that we can access them.
 * @pm8001_ha:our hba structure.
 */
static int pm8001_ioremap(struct pm8001_hba_info *pm8001_ha)
{
	u32 bar;
	u32 logicalBar = 0;
	struct pci_dev *pdev;

	pdev = pm8001_ha->pdev;
	/* map pci mem (PMC pci base 0-3)*/
	for (bar = 0; bar < 6; bar++) {
		/*
		** logical BARs for SPC:
		** bar 0 and 1 - logical BAR0
		** bar 2 and 3 - logical BAR1
		** bar4 - logical BAR2
		** bar5 - logical BAR3
		** Skip the appropriate assignments:
		*/
		if ((bar == 1) || (bar == 3))
			continue;
		if (pci_resource_flags(pdev, bar) & IORESOURCE_MEM) {
			pm8001_ha->io_mem[logicalBar].membase =
				pci_resource_start(pdev, bar);
			pm8001_ha->io_mem[logicalBar].membase &=
				(u32)PCI_BASE_ADDRESS_MEM_MASK;
			p