[PATCH 8/8] cxl/acpi: Add module parameters to stand in for ACPI tables

From: Dan Williams
Date: Wed Mar 24 2021 - 17:32:09 EST


[debug / to-be-replaced / not-for-upstream]

Given ACPICA support is needed before drivers can integrate ACPI
functionality add some module parameters as proxies.
---
drivers/cxl/acpi.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 79 insertions(+), 2 deletions(-)

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
index bc2a35ae880b..2a48a728f3e0 100644
--- a/drivers/cxl/acpi.c
+++ b/drivers/cxl/acpi.c
@@ -4,10 +4,84 @@
#include <linux/module.h>
#include <linux/device.h>
#include <linux/kernel.h>
+#include <linux/range.h>
#include <linux/acpi.h>
#include <linux/pci.h>
#include "cxl.h"

+/*
+ * TODO: Replace all of the below module parameters with ACPI CXL
+ * resource descriptions once ACPICA makes them available.
+ */
+static unsigned long chbcr[4];
+module_param_named(chbcr0, chbcr[0], ulong, 0400);
+module_param_named(chbcr1, chbcr[1], ulong, 0400);
+module_param_named(chbcr2, chbcr[2], ulong, 0400);
+module_param_named(chbcr3, chbcr[3], ulong, 0400);
+
+/* TODO: cross-bridge interleave */
+static struct cxl_address_space cxl_space[] = {
+ [0] = { .range = { 0, -1 }, .targets = 0x1, },
+ [1] = { .range = { 0, -1 }, .targets = 0x1, },
+ [2] = { .range = { 0, -1 }, .targets = 0x1, },
+ [3] = { .range = { 0, -1 }, .targets = 0x1, },
+};
+
+static int set_range(const char *val, const struct kernel_param *kp)
+{
+ unsigned long long size, base;
+ struct cxl_address_space *space;
+ unsigned long flags;
+ char *p;
+ int rc;
+
+ size = memparse(val, &p);
+ if (*p != '@')
+ return -EINVAL;
+
+ base = memparse(p + 1, &p);
+ if (*p != ':')
+ return -EINVAL;
+
+ rc = kstrtoul(p + 1, 0, &flags);
+ if (rc)
+ return rc;
+ if (!flags || flags > CXL_ADDRSPACE_MASK)
+ return rc;
+
+ space = kp->arg;
+ *space = (struct cxl_address_space) {
+ .range = {
+ .start = base,
+ .end = base + size - 1,
+ },
+ .flags = flags,
+ };
+
+ return 0;
+}
+
+static int get_range(char *buf, const struct kernel_param *kp)
+{
+ struct cxl_address_space *space = kp->arg;
+
+ if (!range_len(&space->range))
+ return -EINVAL;
+
+ return sysfs_emit(buf, "%#llx@%#llx :%s%s%s%s\n",
+ (unsigned long long)range_len(&space->range),
+ (unsigned long long)space->range.start,
+ space->flags & CXL_ADDRSPACE_RAM ? " ram" : "",
+ space->flags & CXL_ADDRSPACE_PMEM ? " pmem" : "",
+ space->flags & CXL_ADDRSPACE_TYPE2 ? " type2" : "",
+ space->flags & CXL_ADDRSPACE_TYPE3 ? " type3" : "");
+}
+
+module_param_call(range0, set_range, get_range, &cxl_space[0], 0400);
+module_param_call(range1, set_range, get_range, &cxl_space[1], 0400);
+module_param_call(range2, set_range, get_range, &cxl_space[2], 0400);
+module_param_call(range3, set_range, get_range, &cxl_space[3], 0400);
+
static int match_ACPI0016(struct device *dev, const void *host)
{
struct acpi_device *adev = to_acpi_device(dev);
@@ -67,13 +141,16 @@ static int cxl_acpi_register_ports(struct device *dev, struct acpi_device *root,
struct cxl_port *port, int idx)
{
struct acpi_pci_root *pci_root = acpi_pci_find_root(root->handle);
+ resource_size_t chbcr_base = ~0ULL;
struct cxl_walk_context ctx;

if (!pci_root)
return -ENXIO;

/* TODO: fold in CEDT.CHBS retrieval */
- port = devm_cxl_add_port(dev, port, &root->dev, idx, ~0ULL);
+ if (idx < ARRAY_SIZE(chbcr))
+ chbcr_base = chbcr[idx];
+ port = devm_cxl_add_port(dev, port, &root->dev, idx, chbcr_base);
if (IS_ERR(port))
return PTR_ERR(port);
dev_dbg(dev, "%s: register: %s\n", dev_name(&root->dev),
@@ -99,7 +176,7 @@ static int cxl_acpi_probe(struct platform_device *pdev)
struct cxl_root *cxl_root;
int rc, i = 0;

- cxl_root = devm_cxl_add_root(dev, NULL, 0);
+ cxl_root = devm_cxl_add_root(dev, cxl_space, ARRAY_SIZE(cxl_space));
if (IS_ERR(cxl_root))
return PTR_ERR(cxl_root);
dev_dbg(dev, "register: %s\n", dev_name(&cxl_root->port.dev));