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Commit 71d41257 authored by Hemant Kumar's avatar Hemant Kumar Committed by Gerrit - the friendly Code Review server
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pic: msm: Add support for ep config space access via sysfs 



Perform ep config space dword read and write using 16-bit BDF,
offset and value to write as input.

To perform config space read for vendor and device id for BDF
0x200

echo 0x200 0x0 > config_dwrod_read

To perform config space write on status and control offset with
write value 0x400 for BDF 0x200

echo 0x200 0x4 0x400 > config_dword_write

Usage information is provided by reading config_dword_read and
config_dword_write.

Change-Id: Ia733b7102bb5961e7ab3b27d4438460e52a51c57
Signed-off-by: default avatarHemant Kumar <hemantk@codeaurora.org>
parent 631faf6b

drivers/pci/controller/pci-msm.c

+86 −0
Original line number Diff line number Diff line
@@ -1308,6 +1308,8 @@ static void msm_pcie_check_l1ss_support_all(struct msm_pcie_dev_t *dev); 


static void msm_pcie_config_aspm(struct msm_pcie_dev_t *dev);



static struct pci_dev *find_pci_dev_from_bdf(u16 bdf, int domain);



static u32 msm_pcie_reg_copy(struct msm_pcie_dev_t *pcie_dev,

		u8 *buf, u32 size, void __iomem *base,

		struct msm_pcie_reg_dump_t *reg_list,
@@ -2179,11 +2181,95 @@ static ssize_t l23_rdy_poll_timeout_store(struct device *dev, 
}

static DEVICE_ATTR_RW(l23_rdy_poll_timeout);



static ssize_t config_dword_read_show(struct device *dev,

					struct device_attribute *attr,

					char *buf)

{

	return scnprintf(buf, PAGE_SIZE,

			 "usage: echo bdf(hex) offset(hex) > config_dword_read\n");

}



static ssize_t config_dword_read_store(struct device *dev,

					struct device_attribute *attr,

					const char *buf, size_t count)

{

	int input[2] = {0}, val, argc;

	struct pci_dev *pci_ep_dev;

	struct msm_pcie_dev_t *pcie_dev = dev_get_drvdata(dev);



	/* input [0]: bdf input[1]: offset to ep config space */

	argc = sscanf(buf, "%x %x", &input[0], &input[1]);

	if (argc != 2 || !input[0] || input[0] >= U16_MAX ||

	    input[1] > SZ_4K) {

		pr_err("for usage: cat config_dword_read\n");

		return -EINVAL;

	}



	pci_ep_dev = find_pci_dev_from_bdf(input[0],

					   pci_domain_nr(pcie_dev->dev->bus));

	if (!pci_ep_dev) {

		pr_err("PCIe: RC%d: pci dev for bdf 0x%04x not found\n",

		       pcie_dev->rc_idx, input[0]);

		return -ENODEV;

	}



	pci_read_config_dword(pci_ep_dev, input[1], &val);



	pr_info("PCIe: RC%d: bdf 0x%04x: offset: 0x%04x val: 0x%08x\n",

		pcie_dev->rc_idx, input[0], input[1], val);



	return count;

}

static DEVICE_ATTR_RW(config_dword_read);



static ssize_t config_dword_write_show(struct device *dev,

					struct device_attribute *attr,

					char *buf)

{

	return scnprintf(buf, PAGE_SIZE,

			 "usage: echo bdf(hex) offset(hex) val(hex) > config_dword_write\n");

}



static ssize_t config_dword_write_store(struct device *dev,

					struct device_attribute *attr,

					const char *buf, size_t count)

{

	int input[3] = {0}, argc;

	struct pci_dev *pci_ep_dev;

	struct msm_pcie_dev_t *pcie_dev = dev_get_drvdata(dev);



	/* input[0]: bdf input[1]: offset to ep config space input[2]: val */

	argc = sscanf(buf, "%x %x %x", &input[0], &input[1], &input[2]);

	if (argc != 3 || !input[0] || input[0] >= U16_MAX ||

	    input[1] > SZ_4K) {

		pr_err("for usage: cat config_dword_write\n");

		return -EINVAL;

	}



	pci_ep_dev = find_pci_dev_from_bdf(input[0],

					   pci_domain_nr(pcie_dev->dev->bus));

	if (!pci_ep_dev) {

		pr_err("PCIe: RC%d: pci dev for bdf 0x%04x not found\n",

		       pcie_dev->rc_idx, input[0]);

		return -ENODEV;

	}



	pr_info("PCIe: RC%d: bdf 0x%04x: offset: 0x%04x val: 0x%08x\n",

		pcie_dev->rc_idx, input[0], input[1], input[2]);



	pci_write_config_dword(pci_ep_dev, input[1], input[2]);



	return count;

}

static DEVICE_ATTR_RW(config_dword_write);



static struct attribute *msm_pcie_debug_attrs[] = {

	&dev_attr_link_check_max_count.attr,

	&dev_attr_enumerate.attr,

	&dev_attr_aspm_stat.attr,

	&dev_attr_l23_rdy_poll_timeout.attr,

	&dev_attr_config_dword_read.attr,

	&dev_attr_config_dword_write.attr,

	NULL,

};