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cxl/pci: Implement wait for media active

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CXL 2.0 8.1.3.8.2 states:

  Memory_Active: When set, indicates that the CXL Range 1 memory is
  fully initialized and available for software use. Must be set within
  Range 1. Memory_Active_Timeout of deassertion of reset to CXL device
  if CXL.mem HwInit Mode=1

Unfortunately, Memory_Active can take quite a long time depending on
media size (up to 256s per 2.0 spec). Provide a callback for the
eventual establishment of CXL.mem operations via the 'cxl_mem' driver
the 'struct cxl_memdev'. The implementation waits for 60s by default for
now and can be overridden by the mbox_ready_time module parameter.

Signed-off-by: Ben Widawsky <ben.widawsky@intel.com>
[djbw: switch to sleeping wait]
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/164298427373.3018233.9309741847039301834.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Ben Widawsky 2022-01-23 16:31:13 -08:00 committed by Dan Williams
parent 560f785590
commit 523e594d9c
3 changed files with 58 additions and 1 deletions
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2
drivers/cxl/cxlmem.h
View file

@ -132,6 +132,7 @@ struct cxl_endpoint_dvsec_info {
* @component_reg_phys: register base of component registers
* @info: Cached DVSEC information about the device.
* @mbox_send: @dev specific transport for transmitting mailbox commands
* @wait_media_ready: @dev specific method to await media ready
*
* See section 8.2.9.5.2 Capacity Configuration and Label Storage for
* details on capacity parameters.
@ -165,6 +166,7 @@ struct cxl_dev_state {
struct cxl_endpoint_dvsec_info info;
int (*mbox_send)(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *cmd);
int (*wait_media_ready)(struct cxl_dev_state *cxlds);
};
enum cxl_opcode {

49
drivers/cxl/pci.c
View file

@ -49,7 +49,7 @@
static unsigned short mbox_ready_timeout = 60;
module_param(mbox_ready_timeout, ushort, 0644);
MODULE_PARM_DESC(mbox_ready_timeout,
"seconds to wait for mailbox ready status");
"seconds to wait for mailbox ready / memory active status");
static int cxl_pci_mbox_wait_for_doorbell(struct cxl_dev_state *cxlds)
{
@ -418,6 +418,51 @@ static int wait_for_valid(struct cxl_dev_state *cxlds)
return -ETIMEDOUT;
}
/*
* Wait up to @mbox_ready_timeout for the device to report memory
* active.
*/
static int wait_for_media_ready(struct cxl_dev_state *cxlds)
{
struct pci_dev *pdev = to_pci_dev(cxlds->dev);
int d = cxlds->cxl_dvsec;
bool active = false;
u64 md_status;
int rc, i;
rc = wait_for_valid(cxlds);
if (rc)
return rc;
for (i = mbox_ready_timeout; i; i--) {
u32 temp;
int rc;
rc = pci_read_config_dword(
pdev, d + CXL_DVSEC_RANGE_SIZE_LOW(0), &temp);
if (rc)
return rc;
active = FIELD_GET(CXL_DVSEC_MEM_ACTIVE, temp);
if (active)
break;
msleep(1000);
}
if (!active) {
dev_err(&pdev->dev,
"timeout awaiting memory active after %d seconds\n",
mbox_ready_timeout);
return -ETIMEDOUT;
}
md_status = readq(cxlds->regs.memdev + CXLMDEV_STATUS_OFFSET);
if (!CXLMDEV_READY(md_status))
return -EIO;
return 0;
}
static int cxl_dvsec_ranges(struct cxl_dev_state *cxlds)
{
struct cxl_endpoint_dvsec_info *info = &cxlds->info;
@ -528,6 +573,8 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
dev_warn(&pdev->dev,
"Device DVSEC not present, skip CXL.mem init\n");
cxlds->wait_media_ready = wait_for_media_ready;
rc = cxl_setup_regs(pdev, CXL_REGLOC_RBI_MEMDEV, &map);
if (rc)
return rc;

8
tools/testing/cxl/test/mem.c
View file

@ -4,6 +4,7 @@
#include <linux/platform_device.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/sizes.h>
#include <linux/bits.h>
#include <cxlmem.h>
@ -236,6 +237,12 @@ static int cxl_mock_mbox_send(struct cxl_dev_state *cxlds, struct cxl_mbox_cmd *
return rc;
}
static int cxl_mock_wait_media_ready(struct cxl_dev_state *cxlds)
{
msleep(100);
return 0;
}
static void label_area_release(void *lsa)
{
vfree(lsa);
@ -262,6 +269,7 @@ static int cxl_mock_mem_probe(struct platform_device *pdev)
return PTR_ERR(cxlds);
cxlds->mbox_send = cxl_mock_mbox_send;
cxlds->wait_media_ready = cxl_mock_wait_media_ready;
cxlds->payload_size = SZ_4K;
rc = cxl_enumerate_cmds(cxlds);