thodg/cgminer

diff --git a/cgminer.c b/cgminer.c
index 55d3943..c0084ab 100644
--- a/cgminer.c
+++ b/cgminer.c
@@ -107,6 +107,9 @@ int opt_dynamic_interval = 7;
 int nDevs;
 int opt_g_threads = 2;
 int gpu_threads;
+#ifdef USE_SCRYPT
+bool opt_scrypt;
+#endif
 #endif
 bool opt_restart = true;
 static bool opt_nogpu;
@@ -863,7 +866,7 @@ static struct opt_table opt_config_table[] = {
 #ifdef HAVE_OPENCL
 	OPT_WITH_ARG("--kernel|-k",
 		     set_kernel, NULL, NULL,
-		     "Override kernel to use (diablo, poclbm, phatk or diakgcn) - one value or comma separated"),
+		     "Override sha256 kernel to use (diablo, poclbm, phatk or diakgcn) - one value or comma separated"),
 #endif
 #ifdef USE_ICARUS
 	OPT_WITH_ARG("--icarus-timing",
@@ -953,6 +956,11 @@ static struct opt_table opt_config_table[] = {
 	OPT_WITH_ARG("--sched-stop",
 		     set_schedtime, NULL, &schedstop,
 		     "Set a time of day in HH:MM to stop mining (will quit without a start time)"),
+#ifdef USE_SCRYPT
+	OPT_WITHOUT_ARG("--scrypt",
+			opt_set_bool, &opt_scrypt,
+			"Use the scrypt algorithm for mining (litecoin only)"),
+#endif
 	OPT_WITH_ARG("--sharelog",
 		     set_sharelog, NULL, NULL,
 		     "Append share log to file"),
diff --git a/driver-opencl.c b/driver-opencl.c
index e8a901d..0d77b4a 100644
--- a/driver-opencl.c
+++ b/driver-opencl.c
@@ -137,7 +137,7 @@ static enum cl_kernels select_kernel(char *arg)
 		return KL_POCLBM;
 	if (!strcmp(arg, "phatk"))
 		return KL_PHATK;
-#ifdef HAVE_SCRYPT
+#ifdef USE_SCRYPT
 	if (!strcmp(arg, "scrypt"))
 		return KL_SCRYPT;
 #endif
@@ -150,6 +150,8 @@ char *set_kernel(char *arg)
 	int i, device = 0;
 	char *nextptr;
 
+	if (opt_scrypt)
+		return "Cannot use sha256 kernel with scrypt";
 	nextptr = strtok(arg, ",");
 	if (nextptr == NULL)
 		return "Invalid parameters for set kernel";
@@ -990,7 +992,7 @@ static cl_int queue_diablo_kernel(_clState *clState, dev_blk_ctx *blk, cl_uint t
 	return status;
 }
 
-#ifdef HAVE_SCRYPT
+#ifdef USE_SCRYPT
 static cl_int queue_scrypt_kernel(_clState *clState, dev_blk_ctx *blk, cl_uint threads)
 {
 	cl_int status = 0;
@@ -1254,25 +1256,25 @@ static bool opencl_thread_prepare(struct thr_info *thr)
 	if (!cgpu->kname)
 	{
 		switch (clStates[i]->chosen_kernel) {
-		case KL_DIABLO:
-			cgpu->kname = "diablo";
-			break;
-		case KL_DIAKGCN:
-			cgpu->kname = "diakgcn";
-			break;
-		case KL_PHATK:
-			cgpu->kname = "phatk";
-			break;
-#ifdef HAVE_SCRYPT
-		case KL_SCRYPT:
-			cgpu->kname = "scrypt";
-			break;
+			case KL_DIABLO:
+				cgpu->kname = "diablo";
+				break;
+			case KL_DIAKGCN:
+				cgpu->kname = "diakgcn";
+				break;
+			case KL_PHATK:
+				cgpu->kname = "phatk";
+				break;
+#ifdef USE_SCRYPT
+			case KL_SCRYPT:
+				cgpu->kname = "scrypt";
+				break;
 #endif
-		case KL_POCLBM:
-			cgpu->kname = "poclbm";
-			break;
-		default:
-			break;
+			case KL_POCLBM:
+				cgpu->kname = "poclbm";
+				break;
+			default:
+				break;
 		}
 	}
 	applog(LOG_INFO, "initCl() finished. Found %s", name);
@@ -1309,7 +1311,7 @@ static bool opencl_thread_init(struct thr_info *thr)
 		case KL_DIAKGCN:
 			thrdata->queue_kernel_parameters = &queue_diakgcn_kernel;
 			break;
-#ifdef HAVE_SCRYPT
+#ifdef USE_SCRYPT
 		case KL_SCRYPT:
 			thrdata->queue_kernel_parameters = &queue_scrypt_kernel;
 			break;
diff --git a/miner.h b/miner.h
index 7482473..c1cbe74 100644
--- a/miner.h
+++ b/miner.h
@@ -262,7 +262,7 @@ enum cl_kernels {
 	KL_PHATK,
 	KL_DIAKGCN,
 	KL_DIABLO,
-#ifdef HAVE_SCRYPT
+#ifdef USE_SCRYPT
 	KL_SCRYPT,
 #endif
 };
@@ -620,6 +620,11 @@ extern bool use_syslog;
 extern struct thr_info *thr_info;
 extern struct cgpu_info gpus[MAX_GPUDEVICES];
 extern int gpu_threads;
+#ifdef USE_SCRYPT
+extern bool opt_scrypt;
+#else
+#define opt_scrypt (0)
+#endif
 extern double total_secs;
 extern int mining_threads;
 extern struct cgpu_info *cpus;
diff --git a/ocl.c b/ocl.c
index 464cb4e..7b80257 100644
--- a/ocl.c
+++ b/ocl.c
@@ -354,8 +354,11 @@ _clState *initCl(unsigned int gpu, char *name, size_t nameSize)
 	char numbuf[10];
 
 	if (gpus[gpu].kernel == KL_NONE) {
-		/* Detect all 2.6 SDKs not with Tahiti and use diablo kernel */
-		if (!strstr(name, "Tahiti") &&
+		if (opt_scrypt) {
+			applog(LOG_INFO, "Selecting scrypt kernel");
+			clState->chosen_kernel = KL_SCRYPT;
+		} else if (!strstr(name, "Tahiti") &&
+			/* Detect all 2.6 SDKs not with Tahiti and use diablo kernel */
 			(strstr(vbuff, "844.4") ||  // Linux 64 bit ATI 2.6 SDK
 			 strstr(vbuff, "851.4") ||  // Windows 64 bit ""
 			 strstr(vbuff, "831.4") ||
@@ -407,6 +410,10 @@ _clState *initCl(unsigned int gpu, char *name, size_t nameSize)
 			strcpy(filename, DIAKGCN_KERNNAME".cl");
 			strcpy(binaryfilename, DIAKGCN_KERNNAME);
 			break;
+		case KL_SCRYPT:
+			strcpy(filename, SCRYPT_KERNNAME".cl");
+			strcpy(binaryfilename, SCRYPT_KERNNAME);
+			break;
 		case KL_NONE: /* Shouldn't happen */
 		case KL_DIABLO:
 			strcpy(filename, DIABLO_KERNNAME".cl");
@@ -528,8 +535,13 @@ build:
 	/* create a cl program executable for all the devices specified */
 	char *CompilerOptions = calloc(1, 256);
 
-	sprintf(CompilerOptions, "-D WORKSIZE=%d -D VECTORS%d -D WORKVEC=%d",
-		(int)clState->wsize, clState->vwidth, (int)clState->wsize * clState->vwidth);
+	if (opt_scrypt) {
+		sprintf(CompilerOptions, "-D LOOKUP_GAP=2 -D CONCURRENT_THREADS=6144 -D WORKSIZE=%d",
+			(int)clState->wsize);
+	} else {
+		sprintf(CompilerOptions, "-D WORKSIZE=%d -D VECTORS%d -D WORKVEC=%d",
+			(int)clState->wsize, clState->vwidth, (int)clState->wsize * clState->vwidth);
+	}
 	applog(LOG_DEBUG, "Setting worksize to %d", clState->wsize);
 	if (clState->vwidth > 1)
 		applog(LOG_DEBUG, "Patched source to suit %d vectors", clState->vwidth);