asix-sigma: Remove stack-based alloc in download_capture()

Avoid allocating 32KiB of data on stack in download_capture(). Instead,
do a glib-variant of calloc(1, ) to allocate the data for the samples
which will be downloaded. This avoids explosions of stack on systems
with tight stack limits.

Furthermore, define structures describing the organisation of Sigma's
DRAM memory and start using those instead of ad-hoc preprocessor macros
defining the sizes of various structures in memory.

Signed-off-by: Marek Vasut <redacted>

diff --git a/hardware/asix-sigma/asix-sigma.c b/hardware/asix-sigma/asix-sigma.c
index c44bae7ab9bb3b7fde085a178795458ab9515abb..7e4b3caa79ce21ae8ca75d4adb3f7953dbdf2307 100644 (file)
--- a/hardware/asix-sigma/asix-sigma.c
+++ b/hardware/asix-sigma/asix-sigma.c
@@ -1073,13 +1073,20 @@ static int download_capture(struct sr_dev_inst *sdi)
 {
        struct dev_context *devc = sdi->priv;
        const int chunks_per_read = 32;
-       unsigned char buf[chunks_per_read * CHUNK_SIZE];
+       struct sigma_dram_line *dram_line;
+       unsigned char *buf;
        int bufsz, i, numchunks, newchunks;
        uint32_t stoppos, triggerpos;
        int triggerchunk, chunks_downloaded;
        struct sr_datafeed_packet packet;
        uint8_t modestatus;
 
+       dram_line = g_try_malloc0(chunks_per_read * sizeof(*dram_line));
+       if (!dram_line)
+               return FALSE;
+
+       buf = (unsigned char *)dram_line;
+
        sr_info("Downloading sample data.");
 
        /* Stop acquisition. */
@@ -1143,6 +1150,8 @@ static int download_capture(struct sr_dev_inst *sdi)
 
        dev_acquisition_stop(sdi, sdi);
 
+       g_free(dram_line);
+
        return TRUE;
 }
 

diff --git a/hardware/asix-sigma/asix-sigma.h b/hardware/asix-sigma/asix-sigma.h
index 193306435db37dfe82dd96990e3e633ebf1f9acf..87c92fb72fbadbb226dde7d6e9967170df10c9ab 100644 (file)
--- a/hardware/asix-sigma/asix-sigma.h
+++ b/hardware/asix-sigma/asix-sigma.h
@@ -76,6 +76,25 @@ enum sigma_read_register {
 
 #define CHUNK_SIZE             1024
 
+/*
+ * The entire ASIX Sigma DRAM is an array of struct sigma_dram_line[1024];
+ */
+
+/* One "DRAM cluster" contains a timestamp and 7 samples, 16b total. */
+struct sigma_dram_cluster {
+       uint8_t         timestamp_lo;
+       uint8_t         timestamp_hi;
+       struct {
+               uint8_t sample_hi;
+               uint8_t sample_lo;
+       }               samples[7];
+};
+
+/* One "DRAM line" contains 64 "DRAM clusters", 1024b total. */
+struct sigma_dram_line {
+       struct sigma_dram_cluster       cluster[64];
+};
+
 struct clockselect_50 {
        uint8_t async;
        uint8_t fraction;