drm/msm/a6xx: Add support for an interconnect path

Try to get the interconnect path for the GPU and vote for the maximum
bandwidth to support all frequencies. This is needed for performance.
Later we will want to scale the bandwidth based on the frequency to
also optimize for power but that will require some device tree
infrastructure that does not yet exist.

v6: use icc_set_bw() instead of icc_set()
v5: Remove hardcoded interconnect name and just use the default
v4: Don't use a port string at all to skip the need for names in the DT
v3: Use macros and change port string per Georgi Djakov

Signed-off-by: Jordan Crouse <[e-mail]>
Acked-by: Rob Clark <[e-mail]>
Reviewed-by: Evan Green <[e-mail]>
Signed-off-by: Georgi Djakov <[e-mail]>
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/gpu/drm/msm/Kconfig

···
 	depends on ARCH_QCOM || SOC_IMX5 || (ARM && COMPILE_TEST)
 	depends on OF && COMMON_CLK
 	depends on MMU
+	depends on INTERCONNECT || !INTERCONNECT
 	select QCOM_MDT_LOADER if ARCH_QCOM
 	select REGULATOR
 	select DRM_KMS_HELPER

drivers/gpu/drm/msm/adreno/a6xx_gmu.c

···
 /* Copyright (c) 2017-2018 The Linux Foundation. All rights reserved. */
 
 #include <linux/clk.h>
+#include <linux/interconnect.h>
 #include <linux/pm_opp.h>
 #include <soc/qcom/cmd-db.h>
 
···
 
 static void __a6xx_gmu_set_freq(struct a6xx_gmu *gmu, int index)
 {
+	struct a6xx_gpu *a6xx_gpu = container_of(gmu, struct a6xx_gpu, gmu);
+	struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
+	struct msm_gpu *gpu = &adreno_gpu->base;
 	int ret;
 
 	gmu_write(gmu, REG_A6XX_GMU_DCVS_ACK_OPTION, 0);
···
 		dev_err(gmu->dev, "GMU set GPU frequency error: %d\n", ret);
 
 	gmu->freq = gmu->gpu_freqs[index];
+
+	/*
+	 * Eventually we will want to scale the path vote with the frequency but
+	 * for now leave it at max so that the performance is nominal.
+	 */
+	icc_set_bw(gpu->icc_path, 0, MBps_to_icc(7216));
 }
 
 void a6xx_gmu_set_freq(struct msm_gpu *gpu, unsigned long freq)
···
 
 int a6xx_gmu_resume(struct a6xx_gpu *a6xx_gpu)
 {
+	struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
+	struct msm_gpu *gpu = &adreno_gpu->base;
 	struct a6xx_gmu *gmu = &a6xx_gpu->gmu;
 	int status, ret;
 
···
 	ret = clk_bulk_prepare_enable(gmu->nr_clocks, gmu->clocks);
 	if (ret)
 		goto out;
+
+	/* Set the bus quota to a reasonable value for boot */
+	icc_set_bw(gpu->icc_path, 0, MBps_to_icc(3072));
 
 	a6xx_gmu_irq_enable(gmu);
 
···
 
 int a6xx_gmu_stop(struct a6xx_gpu *a6xx_gpu)
 {
+	struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
+	struct msm_gpu *gpu = &adreno_gpu->base;
 	struct a6xx_gmu *gmu = &a6xx_gpu->gmu;
 	u32 val;
 
···
 
 	/* Tell RPMh to power off the GPU */
 	a6xx_rpmh_stop(gmu);
+
+	/* Remove the bus vote */
+	icc_set_bw(gpu->icc_path, 0, 0);
 
 	clk_bulk_disable_unprepare(gmu->nr_clocks, gmu->clocks);
 

drivers/gpu/drm/msm/adreno/adreno_gpu.c

···
  */
 
 #include <linux/ascii85.h>
+#include <linux/interconnect.h>
 #include <linux/kernel.h>
 #include <linux/pm_opp.h>
 #include <linux/slab.h>
···
 
 	DBG("fast_rate=%u, slow_rate=27000000", gpu->fast_rate);
 
+	/* Check for an interconnect path for the bus */
+	gpu->icc_path = of_icc_get(dev, NULL);
+	if (IS_ERR(gpu->icc_path))
+		gpu->icc_path = NULL;
+
 	return 0;
 }
 
···
 
 void adreno_gpu_cleanup(struct adreno_gpu *adreno_gpu)
 {
+	struct msm_gpu *gpu = &adreno_gpu->base;
 	unsigned int i;
 
 	for (i = 0; i < ARRAY_SIZE(adreno_gpu->info->fw); i++)
 		release_firmware(adreno_gpu->fw[i]);
+
+	icc_put(gpu->icc_path);
 
 	msm_gpu_cleanup(&adreno_gpu->base);
 }

drivers/gpu/drm/msm/msm_gpu.h

···
 #define __MSM_GPU_H__
 
 #include <linux/clk.h>
+#include <linux/interconnect.h>
 #include <linux/regulator/consumer.h>
 
 #include "msm_drv.h"
···
 	int nr_clocks;
 	struct clk *ebi1_clk, *core_clk, *rbbmtimer_clk;
 	uint32_t fast_rate;
+
+	struct icc_path *icc_path;
 
 	/* Hang and Inactivity Detection:
 	 */