Commit 4474ce56 authored by Dave Jiang's avatar Dave Jiang Committed by Dan Williams
Browse files

cxl/hdm: Create emulated cxl_hdm for devices that do not have HDM decoders 



CXL rev3 spec 8.1.3

RCDs may not have HDM register blocks. Create a fake HDM with information
from the CXL PCIe DVSEC registers. The decoder count will be set to the
HDM count retrieved from the DVSEC cap register.

Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/167640368994.935665.15831225724059704620.stgit@dwillia2-xfh.jf.intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent b777e9be

drivers/cxl/core/hdm.c

+48 −10
Original line number Diff line number Diff line
@@ -101,11 +101,34 @@ static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb, 
				      BIT(CXL_CM_CAP_CAP_ID_HDM));

}



static struct cxl_hdm *devm_cxl_setup_emulated_hdm(struct cxl_port *port,

						   struct cxl_endpoint_dvsec_info *info)

{

	struct device *dev = &port->dev;

	struct cxl_hdm *cxlhdm;



	if (!info->mem_enabled)

		return ERR_PTR(-ENODEV);



	cxlhdm = devm_kzalloc(dev, sizeof(*cxlhdm), GFP_KERNEL);

	if (!cxlhdm)

		return ERR_PTR(-ENOMEM);



	cxlhdm->port = port;

	cxlhdm->decoder_count = info->ranges;

	cxlhdm->target_count = info->ranges;

	dev_set_drvdata(&port->dev, cxlhdm);



	return cxlhdm;

}



/**

 * devm_cxl_setup_hdm - map HDM decoder component registers

 * @port: cxl_port to map

 * @info: cached DVSEC range register info

 */

struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port)

struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port,

				   struct cxl_endpoint_dvsec_info *info)

{

	struct device *dev = &port->dev;

	struct cxl_hdm *cxlhdm;
@@ -119,6 +142,9 @@ struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port) 
	cxlhdm->port = port;

	crb = ioremap(port->component_reg_phys, CXL_COMPONENT_REG_BLOCK_SIZE);

	if (!crb) {

		if (info->mem_enabled)

			return devm_cxl_setup_emulated_hdm(port, info);



		dev_err(dev, "No component registers mapped\n");

		return ERR_PTR(-ENXIO);

	}
@@ -814,19 +840,15 @@ static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld, 
	return 0;

}



/**

 * devm_cxl_enumerate_decoders - add decoder objects per HDM register set

 * @cxlhdm: Structure to populate with HDM capabilities

 */

int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm,

				struct cxl_endpoint_dvsec_info *info)

static void cxl_settle_decoders(struct cxl_hdm *cxlhdm)

{

	void __iomem *hdm = cxlhdm->regs.hdm_decoder;

	struct cxl_port *port = cxlhdm->port;

	int i, committed;

	u64 dpa_base = 0;

	int committed, i;

	u32 ctrl;



	if (!hdm)

		return;



	/*

	 * Since the register resource was recently claimed via request_region()

	 * be careful about trusting the "not-committed" status until the commit
@@ -843,6 +865,22 @@ int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm, 
	/* ensure that future checks of committed can be trusted */

	if (committed != cxlhdm->decoder_count)

		msleep(20);

}



/**

 * devm_cxl_enumerate_decoders - add decoder objects per HDM register set

 * @cxlhdm: Structure to populate with HDM capabilities

 * @info: cached DVSEC range register info

 */

int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm,

				struct cxl_endpoint_dvsec_info *info)

{

	void __iomem *hdm = cxlhdm->regs.hdm_decoder;

	struct cxl_port *port = cxlhdm->port;

	int i;

	u64 dpa_base = 0;



	cxl_settle_decoders(cxlhdm);



	for (i = 0; i < cxlhdm->decoder_count; i++) {

		int target_map[CXL_DECODER_MAX_INTERLEAVE] = { 0 };

drivers/cxl/core/pci.c

+6 −3
Original line number Diff line number Diff line
@@ -378,16 +378,19 @@ int cxl_hdm_decode_init(struct cxl_dev_state *cxlds, struct cxl_hdm *cxlhdm, 
	struct device *dev = cxlds->dev;

	struct cxl_port *root;

	int i, rc, allowed;

	u32 global_ctrl;

	u32 global_ctrl = 0;



	if (hdm)

		global_ctrl = readl(hdm + CXL_HDM_DECODER_CTRL_OFFSET);



	/*

	 * If the HDM Decoder Capability is already enabled then assume

	 * that some other agent like platform firmware set it up.

	 */

	if (global_ctrl & CXL_HDM_DECODER_ENABLE)

	if (global_ctrl & CXL_HDM_DECODER_ENABLE || (!hdm && info->mem_enabled))

		return devm_cxl_enable_mem(&port->dev, cxlds);

	else if (!hdm)

		return -ENODEV;



	root = to_cxl_port(port->dev.parent);

	while (!is_cxl_root(root) && is_cxl_port(root->dev.parent))

drivers/cxl/cxl.h

+2 −1
Original line number Diff line number Diff line
@@ -643,7 +643,8 @@ struct cxl_endpoint_dvsec_info { 
};



struct cxl_hdm;

struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port);

struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port,

				   struct cxl_endpoint_dvsec_info *info);

int devm_cxl_enumerate_decoders(struct cxl_hdm *cxlhdm,

				struct cxl_endpoint_dvsec_info *info);

int devm_cxl_add_passthrough_decoder(struct cxl_port *port);

drivers/cxl/port.c

+1 −1
Original line number Diff line number Diff line
@@ -54,7 +54,7 @@ static int cxl_port_probe(struct device *dev) 
			return devm_cxl_add_passthrough_decoder(port);

	}



	cxlhdm = devm_cxl_setup_hdm(port);

	cxlhdm = devm_cxl_setup_hdm(port, &info);

	if (IS_ERR(cxlhdm))

		return PTR_ERR(cxlhdm);

tools/testing/cxl/test/cxl.c

+2 −1
Original line number Diff line number Diff line
@@ -618,7 +618,8 @@ static struct acpi_pci_root *mock_acpi_pci_find_root(acpi_handle handle) 
	return &mock_pci_root[host_bridge_index(adev)];

}



static struct cxl_hdm *mock_cxl_setup_hdm(struct cxl_port *port)

static struct cxl_hdm *mock_cxl_setup_hdm(struct cxl_port *port,

					  struct cxl_endpoint_dvsec_info *info)

{

	struct cxl_hdm *cxlhdm = devm_kzalloc(&port->dev, sizeof(*cxlhdm), GFP_KERNEL);