Commit 52cc48ad authored by Dan Williams's avatar Dan Williams
Browse files

cxl/hdm: Limit emulation to the number of range registers 



Recall that range register emulation seeks to treat the 2 potential
range registers as Linux CXL "decoder" objects. The number of range
registers can be 1 or 2, while HDM decoder ranges can include more than
2.

Be careful not to confuse DVSEC range count with HDM capability decoder
count. Commit to range register earlier in devm_cxl_setup_hdm().
Otherwise, a device with more HDM decoders than range registers can set
@cxlhdm->decoder_count to an invalid value.

Avoid introducing a forward declaration by just moving the definition of
should_emulate_decoders() earlier in the file. should_emulate_decoders()
is unchanged.

Tested-by: default avatarDave Jiang <dave.jiang@intel.com>
Fixes: d7a21537 ("cxl/hdm: Add emulation when HDM decoders are not committed")
Reviewed-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: default avatarDave Jiang <dave.jiang@intel.com>
Link: https://lore.kernel.org/r/168012574932.221280.15944705098679646436.stgit@dwillia2-xfh.jf.intel.com


Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 9ff3eec9

drivers/cxl/core/hdm.c

+46 −36
Original line number Diff line number Diff line
@@ -101,6 +101,42 @@ static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb, 
				      BIT(CXL_CM_CAP_CAP_ID_HDM));

}



static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)

{

	struct cxl_hdm *cxlhdm;

	void __iomem *hdm;

	u32 ctrl;

	int i;



	if (!info)

		return false;



	cxlhdm = dev_get_drvdata(&info->port->dev);

	hdm = cxlhdm->regs.hdm_decoder;



	if (!hdm)

		return true;



	/*

	 * If HDM decoders are present and the driver is in control of

	 * Mem_Enable skip DVSEC based emulation

	 */

	if (!info->mem_enabled)

		return false;



	/*

	 * If any decoders are committed already, there should not be any

	 * emulated DVSEC decoders.

	 */

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

		ctrl = readl(hdm + CXL_HDM_DECODER0_CTRL_OFFSET(i));

		if (FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl))

			return false;

	}



	return true;

}



/**

 * devm_cxl_setup_hdm - map HDM decoder component registers

 * @port: cxl_port to map
@@ -140,6 +176,16 @@ struct cxl_hdm *devm_cxl_setup_hdm(struct cxl_port *port, 
		return ERR_PTR(-ENXIO);

	}



	/*

	 * Now that the hdm capability is parsed, decide if range

	 * register emulation is needed and fixup cxlhdm accordingly.

	 */

	if (should_emulate_decoders(info)) {

		dev_dbg(dev, "Fallback map %d range register%s\n", info->ranges,

			info->ranges > 1 ? "s" : "");

		cxlhdm->decoder_count = info->ranges;

	}



	return cxlhdm;

}

EXPORT_SYMBOL_NS_GPL(devm_cxl_setup_hdm, CXL);
@@ -717,42 +763,6 @@ static int cxl_setup_hdm_decoder_from_dvsec(struct cxl_port *port, 
	return 0;

}



static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info)

{

	struct cxl_hdm *cxlhdm;

	void __iomem *hdm;

	u32 ctrl;

	int i;



	if (!info)

		return false;



	cxlhdm = dev_get_drvdata(&info->port->dev);

	hdm = cxlhdm->regs.hdm_decoder;



	if (!hdm)

		return true;



	/*

	 * If HDM decoders are present and the driver is in control of

	 * Mem_Enable skip DVSEC based emulation

	 */

	if (!info->mem_enabled)

		return false;



	/*

	 * If any decoders are committed already, there should not be any

	 * emulated DVSEC decoders.

	 */

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

		ctrl = readl(hdm + CXL_HDM_DECODER0_CTRL_OFFSET(i));

		if (FIELD_GET(CXL_HDM_DECODER0_CTRL_COMMITTED, ctrl))

			return false;

	}



	return true;

}



static int init_hdm_decoder(struct cxl_port *port, struct cxl_decoder *cxld,

			    int *target_map, void __iomem *hdm, int which,

			    u64 *dpa_base, struct cxl_endpoint_dvsec_info *info)